windows form application list to ADO.NET datatable

windows form application list to ADO.NET datatable - c#

This is my first question, please ignore my mistakes.
I am running a C# project which passes requirements of twitter feed, 5 attributes in a string named "urlAll". I am going to split the properties with *#06# which I declared before which is given bellow.
public DataTable GetTwitterDataTableMulti(string urlAll)
{
Trace.bDebug = false;
if (ExitNow)
{
return null;
}
string[] allurl = urlAll.Split(new string[] { "*#06#" }, StringSplitOptions.None);
return Dt;
}
I have created another project with windows form application using LinqToTwitter and it returns a list. All I need is to return the list as a ado.net table which I have written before. Below is my twitter feed code.
//initializing a list of current news feeds
private List<Status> currentTweets;
//parent class of the form application
//interface
public TwitterFeed()
{
//initializing the components
InitializeComponent();
//call the function that will display current 200 feeds from twitter
GetMostRecent200HomeTimeLine();
//clearing the textbox in which the feeds will be displayed
lstTweetList.Items.Clear();
//displaying the feed in text box right
currentTweets.ForEach(tweet => lstTweetList.Items.Add(tweet.User.Name + ":" + tweet.Text));
//display follow list in text box left
//GetSideBarList(GetFollowers()).ForEach(name => lstFollowNames.Items.Add(name));
}
//method that gets current 200 feeds form twitter of the user
private void GetMostRecent200HomeTimeLine()
{
var twitterContext = new TwitterContext(authorizer);
var tweets = from tweet in twitterContext.Status
where tweet.Type == StatusType.Home &&
tweet.Count == 200
select tweet;
currentTweets = tweets.ToList();
}
what would be the possible way to integrate them ?

This should work if your list does not have any other collection:
public static DataTable ToDataTable<T>(this IList<T> list)
{
DataTable table = null;
if (list != null && list.Count > 0)
{
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
List<PropertyDescriptor[]> propList = new List<PropertyDescriptor[]>();
table = new DataTable();
foreach (PropertyDescriptor item in properties)
{
if (IsArrayOrCollection(item.PropertyType))
{
continue;
}
AddColumnsForProperties(typeof(T).Namespace, null, table, (new[] { item }).ToList(), ref propList);
}
object[] values = new object[propList.Count];
foreach (T item in list)
{
for (int i = 0; i < values.Length; i++)
values[i] = GetValueFromProps(propList[i], item) ?? DBNull.Value;
table.Rows.Add(values);
}
}
return table;
}
private static object GetValueFromProps(PropertyDescriptor[] descriptors, object item)
{
var result = item;
foreach (var descriptor in descriptors)
{
if (result != null)
{
result = descriptor.GetValue(result);
}
}
return result;
}
private static void AddColumnsForProperties(string myNamespace, string parentName, DataTable dt, List<PropertyDescriptor> p, ref List<PropertyDescriptor[]> properties)
{
var pLast = p.Last();
if (pLast.PropertyType.Namespace != null && pLast.PropertyType.Namespace.StartsWith(myNamespace))
{
var allProperties = pLast.GetChildProperties();
if (allProperties.Count > 0)
{
foreach (PropertyDescriptor item in allProperties)
{
var newP = p.ToList();
newP.Add(item);
string childParentName = !String.IsNullOrEmpty(parentName)
? String.Format("{0}.{1}.{2}", parentName, pLast.Name, item.Name)
: String.Format("{0}.{1}", pLast.Name, item.Name);
if (item.PropertyType.Namespace != null && item.PropertyType.Namespace.ToLower().StartsWith(myNamespace))
{
AddColumnsForProperties(myNamespace, childParentName, dt, newP, ref properties);
}
else if (!dt.Columns.Contains(childParentName))
{
dt.Columns.Add(childParentName, Nullable.GetUnderlyingType(item.PropertyType) ?? item.PropertyType);
properties.Add(newP.ToArray());
}
}
}
else if (!dt.Columns.Contains(pLast.Name))
{
dt.Columns.Add(pLast.Name, Nullable.GetUnderlyingType(pLast.PropertyType) ?? pLast.PropertyType);
properties.Add(p.ToArray());
}
}
else if (!dt.Columns.Contains(pLast.Name))
{
dt.Columns.Add(pLast.Name, Nullable.GetUnderlyingType(pLast.PropertyType) ?? pLast.PropertyType);
properties.Add(p.ToArray());
}
}

Related

How to convert System.Web.Mvc.SelectListItem to list

I want to display data using datatable so my hard coded System.Web.Mvc.SelectListItem value and text collect and make a list using linq but get error System.Linq.Enumerable+WhereSelectListIterator`2[System.Web.Mvc.SelectListItem,System.String]
var parentkeylist = clsDataCache.GetPriorityList().ToList();
var parentkeylist = clsDataCache.GetPriorityList().ToList();//this is SelectListItem
List data = this.GetAllStpOrganizationEntityData(input);
foreach (stp_organizationentityEntity obj in data)
{
if (obj.parentkey != null)
{
obj.priotytext = parentkeylist.Where(x => x.Value == obj.parentkey.ToString()).Select(x => x.Text).Cast<string>().ToString();//not cast Text value get error System.Linq.Enumerable+WhereSelectListIterator`2[System.Web.Mvc.SelectListItem,System.String]
}
else
{
obj.priotytext = "Root";
}
}
if (data != null && data.Count > 0)
{
long totalRecords = data.FirstOrDefault().RETURN_KEY;
var tut = (from t in data
select new
{
t.entityname,
t.organizationkey,
t.priotytext,
t.entirytypekey,
t.entitylevel,
//t.seqfirstindex,
//t.seqfullindex,
// t.entitycpde,
//t.description,
t.isactive,
ex_nvarchar1 = objSecPanel.genButtonPanel(t.entitykey.GetValueOrDefault(-99), "entitykey", this.HttpContext.User.Identity as ClaimsIdentity,
"StpOrganizationEntity/StpOrganizationEntityUpdate", "EditStpOrganizationEntity", "StpOrganizationEntity/StpOrganizationEntityDelete", "DeleteStpOrganizationEntity",
"StpOrganizationEntity/StpOrganizationEntityDetails", "StpOrganizationEntityDetails")
}).ToList();
}
var parentkeylist = clsDataCache.GetPriorityList().ToList();
var parentkeylist = clsDataCache.GetPriorityList().ToList();//this is SelectListItem
List data = this.GetAllStpOrganizationEntityData(input);
foreach (stp_organizationentityEntity obj in data)
{
if (obj.parentkey != null)
{
obj.priotytext = parentkeylist.Where(x => x.Value == obj.parentkey.ToString()).Select(x => x.Text).Cast<string>().ToString();//not cast Text value get error System.Linq.Enumerable+WhereSelectListIterator`2[System.Web.Mvc.SelectListItem,System.String]
}
else
{
obj.priotytext = "Root";
}
}
if (data != null && data.Count > 0)
{
long totalRecords = data.FirstOrDefault().RETURN_KEY;
var tut = (from t in data
select new
{
t.entityname,
t.organizationkey,
t.priotytext,
t.entirytypekey,
t.entitylevel,
//t.seqfirstindex,
//t.seqfullindex,
// t.entitycpde,
//t.description,
t.isactive,
ex_nvarchar1 = objSecPanel.genButtonPanel(t.entitykey.GetValueOrDefault(-99), "entitykey", this.HttpContext.User.Identity as ClaimsIdentity,
"StpOrganizationEntity/StpOrganizationEntityUpdate", "EditStpOrganizationEntity", "StpOrganizationEntity/StpOrganizationEntityDelete", "DeleteStpOrganizationEntity",
"StpOrganizationEntity/StpOrganizationEntityDetails", "StpOrganizationEntityDetails")
}).ToList();
}enter image description here

How to convert nested List to Dataset in C#

I have a nested list and I need to convert it to DataSet in C#. I found many example about this but they dont do what I need. I have a list in a list, I need the nested list in another DataTable in the DataSet.
Here is an example of list
public class InvoiceResponse(){
public string BillToName { get; set; }
public string BillToAddr1 { get; set; }
...
...
public List<InvoiceItemResponse> Items { get; set; }
}
I have used the code below to convert the List to DataSet but It didnt convert Items to DataTable in DataSet
public DataSet CreateDataSet<T>(List<T> list)
{
//list is nothing or has nothing, return nothing (or add exception handling)
if (list == null || list.Count == 0) { return null; }
//get the type of the first obj in the list
var obj = list[0].GetType();
//now grab all properties
var properties = obj.GetProperties();
//make sure the obj has properties, return nothing (or add exception handling)
if (properties.Length == 0) { return null; }
//it does so create the dataset and table
var dataSet = new DataSet();
var dataTable = new DataTable();
//now build the columns from the properties
var columns = new DataColumn[properties.Length];
for (int i = 0; i < properties.Length; i++)
{
columns[i] = new DataColumn(properties[i].Name, properties[i].PropertyType);
}
//add columns to table
dataTable.Columns.AddRange(columns);
//now add the list values to the table
foreach (var item in list)
{
//create a new row from table
var dataRow = dataTable.NewRow();
//now we have to iterate thru each property of the item and retrieve it's value for the corresponding row's cell
var itemProperties = item.GetType().GetProperties();
for (int i = 0; i < itemProperties.Length; i++)
{
dataRow[i] = itemProperties[i].GetValue(item, null);
}
//now add the populated row to the table
dataTable.Rows.Add(dataRow);
}
//add table to dataset
dataSet.Tables.Add(dataTable);
//return dataset
return dataSet;
}
How can I convert the Items list to another DataTable into the DataSet?

You can just add a bit of recursivity to your code, something like this:
var set = new DataSet();
AddToDataSet(set, resp);
...
public static void AddToDataSet(DataSet set, object value)
{
if (set == null)
throw new ArgumentNullException(nameof(set));
if (value == null)
return;
var type = value.GetType();
var table = set.Tables[type.FullName];
if (table == null)
{
// create one table per type (name)
table = new DataTable(type.FullName);
set.Tables.Add(table);
foreach (var prop in type.GetProperties().Where(p => p.CanRead))
{
if (IsEnumerable(prop))
continue;
var col = new DataColumn(prop.Name, prop.PropertyType);
table.Columns.Add(col);
}
}
var row = table.NewRow();
foreach (var prop in type.GetProperties().Where(p => p.CanRead))
{
object propValue = prop.GetValue(value);
if (IsEnumerable(prop))
{
if (propValue != null)
{
foreach (var child in (ICollection)propValue)
{
AddToDataSet(set, child);
}
}
continue;
}
row[prop.Name] = propValue;
}
table.Rows.Add(row);
}
private static bool IsEnumerable(PropertyInfo pi)
{
// note: we could also use IEnumerable (but string, arrays are IEnumerable...)
return typeof(ICollection).IsAssignableFrom(pi.PropertyType);
}

SharePoint people editor not displaying users

I've a requirement in which I've to display the saved users to the SharePoint people editor control. For this, I am saving the user names to People/Group column. And I am using the following code for taking these users to people editor control:
SetPeopleEditor(item, Constants.FieldNames.IT_DIRECTOR, pe_ITDirector, oWeb);
the definition of the above method is shown below:
private PickerEntity SetPeopleEditor(SPListItem item, string columnName, PeopleEditor peopleEditor, SPWeb web)
{
ArrayList entityArrayList = new ArrayList();
PickerEntity entity = null;
if (item[columnName] != null)
{
char[] to_splitter = { ';' };
string to_list = item[columnName].ToString(); // Reads value stored in SPList. (i.e., "Domain\User1; Domain\User2")
string[] arr = to_list.Split(to_splitter);
string user = string.Empty;
for (int i = 1; i < arr.Length; i++)
{
if ((i % 2) != 0)
{
user = arr[i].Substring(arr[i].IndexOf("#") + 1);
entity = new PickerEntity();
entity.Key = user;
entity.IsResolved = true;
entity = peopleEditor.ValidateEntity(entity);
entityArrayList.Add(entity);
}
}
}
return entity;
}
But unfortunately, the control always showing empty value. How can I achieve this by populating data to the people editor control?

You can do as follows,
SPFieldUserValueCollection userValueCollection =
new SPFieldUserValueCollection(SPContext.Current.Web, SPContext.Current.Item["ColumnName"] as string);
if (userValueCollection .Count > 0)
{
spPeoplePickerContol.CommaSeparatedAccounts = userValueCollection[0].User.LoginName;
}

You have to include peopleEditor.Entities.Add(entity) after validating entity to add the entity to peopleEditor control.
private void SetPeopleEditor(SPListItem item, string columnName, PeopleEditor peopleEditor, SPWeb web)
{
if (item[columnName] != null)
{
char[] to_splitter = { ';' };
string to_list = item[columnName].ToString(); // Reads value stored in SPList. (i.e., "Domain\User1; Domain\User2")
string[] arr = to_list.Split(to_splitter);
string user = string.Empty;
for (int i = 1; i < arr.Length; i++)
{
if ((i % 2) != 0)
{
user = arr[i].Substring(arr[i].IndexOf("#") + 1);
PickerEntity entity = new PickerEntity();
entity.Key = user;
entity.IsResolved = true;
entity = peopleEditor.ValidateEntity(entity);
peopleEditor.Entities.Add(entity);
}
}
}
}

Try this:
string x = item["SP_Group"] == null ? "" : item["SP_Group"].ToString();
if (x != "")
{
SPFieldUserValue uv = new SPFieldUserValue(web, x);
SPGroup group = mySite.Groups.GetByID(uv.LookupId);
if (group.Users.Count > 0)
{
System.Collections.ArrayList entityArrayList = new System.Collections.ArrayList();
SPSecurity.RunWithElevatedPrivileges(delegate()
{
foreach (SPUser sUser in group.Users)
{
PickerEntity entity = new PickerEntity();
entity.Key = sUser.LoginName;
entity = peopleEditor.ValidateEntity(entity);
entityArrayList.Add(entity);
}
});
peopleEditor.UpdateEntities(entityArrayList);
peopleEditor.Validate();
}
else
{
peopleEditor.Entities.Clear();
}
}
string x = item["SP_Users"] == null ? "" : item["SP_Users"].ToString();
if (x != "")
{
SPFieldUserValueCollection uvcoll = new SPFieldUserValueCollection(mySite, x);
if (uvcoll.Count > 0)
{
System.Collections.ArrayList entityArrayList = new System.Collections.ArrayList();
SPSecurity.RunWithElevatedPrivileges(delegate()
{
foreach (SPFieldUserValue uv in uvcoll)
{
SPUser sUser = uv.User;
PickerEntity entity = new PickerEntity();
entity.Key = sUser.LoginName;
entity = peopleEditor.ValidateEntity(entity);
entityArrayList.Add(entity);
}
});
peopleEditor.UpdateEntities(entityArrayList);
peopleEditor.Validate();
}
else
{
peopleEditor.Entities.Clear();
}
}

Not Having CopyToDatatable() method

i have a linq to dataTable query like this:
`var ShowResult = from r in Result.AsEnumerable()
where Convert.ToInt32(r.Field<double>("ASLVAM") / r.Field<double>("GEST")) > 60
orderby Convert.ToInt32(r.Field<double>("ASLVAM") / r.Field<double>("GEST")) descending
select new
{
pascode = r.Field<string>("PAS_CODE"),
melli = r.Field<string>("CODEMELI"),
name = r.Field<string>("NAM"),
family = r.Field<string>("FAMILY"),
bycode = r.Field<string>("BAYGANI"),
jancode = r.Field<string>("CODEJANBAZ"),
darsad = r.Field<int>("DARSAD"),
ostan = r.Field<string>("OSTAN_N"),
vacode = r.Field<string>("VA_CODE"),
moin = r.Field<string>("VA_MOIN"),
onvan = r.Field<string>("TAFZILI"),
aslvam = r.Field<double>("ASLVAM"),
gest = r.Field<double>("GEST"),
//tededGestKol = Convert.ToInt32(r.Field<double>("ASLVAM") / r.Field<double>("GEST")),
mandeVam = r.Field<double>("MANDE_VAM"),
dPardakht = r.Field<string>("DATE_P")
};`<code>
and i added reference System.Data.DataSetExtentions to use CopyToDataTable() method for showing my query result in a dataGrid view but this method didn,t add to my Inellisence,
I also use the MSDN Sample to use this method but this time i got this error :
"Specified Cast is not valid"
Please help me , what can i do to overcom this problem?

CopyToDataTable() only works when your query returns an IEnumerable<'DataRow>. In your query, you are returning an anonymous type. Anonymous types don't carry the extension method for CopyToDataTable(). You could just select the entire row like this, assuming Result is a DataTable. Then create your anonymous type.
public static void Start()
{
DataTable Result = new DataTable();
var ShowResult = from r in Result.AsEnumerable()
where Convert.ToInt32(r.Field<double>("ASLVAM") / r.Field<double>("GEST")) > 60
orderby Convert.ToInt32(r.Field<double>("ASLVAM") / r.Field<double>("GEST")) descending
select r;
DataTable newDataTbl = ShowResult.CopyToDataTable();
var anonType = newDataTbl.AsEnumerable()
.Select(r => new
{
pascode = r.Field<string>("PAS_CODE"),
melli = r.Field<string>("CODEMELI"),
name = r.Field<string>("NAM"),
family = r.Field<string>("FAMILY"),
bycode = r.Field<string>("BAYGANI"),
jancode = r.Field<string>("CODEJANBAZ"),
darsad = r.Field<int>("DARSAD"),
ostan = r.Field<string>("OSTAN_N"),
vacode = r.Field<string>("VA_CODE"),
moin = r.Field<string>("VA_MOIN"),
onvan = r.Field<string>("TAFZILI"),
aslvam = r.Field<double>("ASLVAM"),
gest = r.Field<double>("GEST"),
//tededGestKol = Convert.ToInt32(r.Field<double>("ASLVAM") / r.Field<double>("GEST")),
mandeVam = r.Field<double>("MANDE_VAM"),
dPardakht = r.Field<string>("DATE_P")
}
);
}
In lieu of the former method, you could use the following extension methods to create a Datatable from a List<'T>.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.ComponentModel;
using System.Reflection;
namespace Common
{
public static class DataTableExtensions
{
public static DataTable ConvertToDataTable<T>(this IList<T> data)
{
PropertyDescriptorCollection properties =
TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
foreach (PropertyDescriptor prop in properties)
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
foreach (T item in data)
{
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
table.Rows.Add(row);
}
table.AcceptChanges();
return table;
}
public static DataRow ConvertToDataRow<T>(this T item, DataTable table)
{
PropertyDescriptorCollection properties =
TypeDescriptor.GetProperties(typeof(T));
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
return row;
}
public static T ConvertToEntity<T>(this DataRow tableRow) where T : new()
{
// Create a new type of the entity I want
Type t = typeof(T);
T returnObject = new T();
foreach (DataColumn col in tableRow.Table.Columns)
{
string colName = col.ColumnName;
// Look for the object's property with the columns name, ignore case
PropertyInfo pInfo = t.GetProperty(colName.ToLower(),
BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance);
// did we find the property ?
if (pInfo != null)
{
object val = tableRow[colName];
// is this a Nullable<> type
bool IsNullable = (Nullable.GetUnderlyingType(pInfo.PropertyType) != null);
if (IsNullable)
{
if (val is System.DBNull)
{
val = null;
}
else
{
// Convert the db type into the T we have in our Nullable<T> type
val = Convert.ChangeType(val, Nullable.GetUnderlyingType(pInfo.PropertyType));
}
}
else
{
// Convert the db type into the type of the property in our entity
SetDefaultValue(ref val, pInfo.PropertyType);
if (pInfo.PropertyType.IsEnum && !pInfo.PropertyType.IsGenericType)
{
val = Enum.ToObject(pInfo.PropertyType, val);
}
else
val = Convert.ChangeType(val, pInfo.PropertyType);
}
// Set the value of the property with the value from the db
if (pInfo.CanWrite)
pInfo.SetValue(returnObject, val, null);
}
}
// return the entity object with values
return returnObject;
}
private static void SetDefaultValue(ref object val, Type propertyType)
{
if (val is DBNull)
{
val = GetDefault(propertyType);
}
}
public static object GetDefault(Type type)
{
if (type.IsValueType)
{
return Activator.CreateInstance(type);
}
return null;
}
public static List<T> ConvertToList<T>(this DataTable table) where T : new()
{
Type t = typeof(T);
// Create a list of the entities we want to return
List<T> returnObject = new List<T>();
// Iterate through the DataTable's rows
foreach (DataRow dr in table.Rows)
{
// Convert each row into an entity object and add to the list
T newRow = dr.ConvertToEntity<T>();
returnObject.Add(newRow);
}
// Return the finished list
return returnObject;
}
}
}

Convert generic List/Enumerable to DataTable?

I have few methods that returns different Generic Lists.
Exists in .net any class static method or whatever to convert any list into a datatable? The only thing that i can imagine is use Reflection to do this.
IF i have this:
List<Whatever> whatever = new List<Whatever>();
(This next code doesn't work of course, but i would like to have the possibility of:
DataTable dt = (DataTable) whatever;

Here's a nice 2013 update using FastMember from NuGet:
IEnumerable<SomeType> data = ...
DataTable table = new DataTable();
using(var reader = ObjectReader.Create(data)) {
table.Load(reader);
}
This uses FastMember's meta-programming API for maximum performance. If you want to restrict it to particular members (or enforce the order), then you can do that too:
IEnumerable<SomeType> data = ...
DataTable table = new DataTable();
using(var reader = ObjectReader.Create(data, "Id", "Name", "Description")) {
table.Load(reader);
}
Editor's Dis/claimer: FastMember is a Marc Gravell project. It's gold and full-on flies!
Yes, this is pretty much the exact opposite of this one; reflection would suffice - or if you need quicker, HyperDescriptor in 2.0, or maybe Expression in 3.5. Actually, HyperDescriptor should be more than adequate.
For example:
// remove "this" if not on C# 3.0 / .NET 3.5
public static DataTable ToDataTable<T>(this IList<T> data)
{
PropertyDescriptorCollection props =
TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
for(int i = 0 ; i < props.Count ; i++)
{
PropertyDescriptor prop = props[i];
table.Columns.Add(prop.Name, prop.PropertyType);
}
object[] values = new object[props.Count];
foreach (T item in data)
{
for (int i = 0; i < values.Length; i++)
{
values[i] = props[i].GetValue(item);
}
table.Rows.Add(values);
}
return table;
}
Now with one line you can make this many many times faster than reflection (by enabling HyperDescriptor for the object-type T).
Edit re performance query; here's a test rig with results:
Vanilla 27179
Hyper 6997
I suspect that the bottleneck has shifted from member-access to DataTable performance... I doubt you'll improve much on that...
Code:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
public class MyData
{
public int A { get; set; }
public string B { get; set; }
public DateTime C { get; set; }
public decimal D { get; set; }
public string E { get; set; }
public int F { get; set; }
}
static class Program
{
static void RunTest(List<MyData> data, string caption)
{
GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
GC.WaitForPendingFinalizers();
GC.WaitForFullGCComplete();
Stopwatch watch = Stopwatch.StartNew();
for (int i = 0; i < 500; i++)
{
data.ToDataTable();
}
watch.Stop();
Console.WriteLine(caption + "\t" + watch.ElapsedMilliseconds);
}
static void Main()
{
List<MyData> foos = new List<MyData>();
for (int i = 0 ; i < 5000 ; i++ ){
foos.Add(new MyData
{ // just gibberish...
A = i,
B = i.ToString(),
C = DateTime.Now.AddSeconds(i),
D = i,
E = "hello",
F = i * 2
});
}
RunTest(foos, "Vanilla");
Hyper.ComponentModel.HyperTypeDescriptionProvider.Add(
typeof(MyData));
RunTest(foos, "Hyper");
Console.ReadLine(); // return to exit
}
}

I had to modify Marc Gravell's sample code to handle nullable types and null values. I have included a working version below. Thanks Marc.
public static DataTable ToDataTable<T>(this IList<T> data)
{
PropertyDescriptorCollection properties =
TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
foreach (PropertyDescriptor prop in properties)
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
foreach (T item in data)
{
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
table.Rows.Add(row);
}
return table;
}

This is a simple mix of the solutions.
It work with Nullable types.
public static DataTable ToDataTable<T>(this IList<T> list)
{
PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
for (int i = 0; i < props.Count; i++)
{
PropertyDescriptor prop = props[i];
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
}
object[] values = new object[props.Count];
foreach (T item in list)
{
for (int i = 0; i < values.Length; i++)
values[i] = props[i].GetValue(item) ?? DBNull.Value;
table.Rows.Add(values);
}
return table;
}

A small change to Marc's answer to make it work with value types like List<string> to data table:
public static DataTable ListToDataTable<T>(IList<T> data)
{
DataTable table = new DataTable();
//special handling for value types and string
if (typeof(T).IsValueType || typeof(T).Equals(typeof(string)))
{
DataColumn dc = new DataColumn("Value", typeof(T));
table.Columns.Add(dc);
foreach (T item in data)
{
DataRow dr = table.NewRow();
dr[0] = item;
table.Rows.Add(dr);
}
}
else
{
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
foreach (PropertyDescriptor prop in properties)
{
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
}
foreach (T item in data)
{
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
{
try
{
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
}
catch (Exception ex)
{
row[prop.Name] = DBNull.Value;
}
}
table.Rows.Add(row);
}
}
return table;
}

Another approach is the above:
List<WhateEver> lst = getdata();
string json = Newtonsoft.Json.JsonConvert.SerializeObject(lst);
DataTable pDt = JsonConvert.DeserializeObject<DataTable>(json);

This link on MSDN is worth a visit: How to: Implement CopyToDataTable<T> Where the Generic Type T Is Not a DataRow
This adds an extension method that lets you do this:
// Create a sequence.
Item[] items = new Item[]
{ new Book{Id = 1, Price = 13.50, Genre = "Comedy", Author = "Gustavo Achong"},
new Book{Id = 2, Price = 8.50, Genre = "Drama", Author = "Jessie Zeng"},
new Movie{Id = 1, Price = 22.99, Genre = "Comedy", Director = "Marissa Barnes"},
new Movie{Id = 1, Price = 13.40, Genre = "Action", Director = "Emmanuel Fernandez"}};
// Query for items with price greater than 9.99.
var query = from i in items
where i.Price > 9.99
orderby i.Price
select i;
// Load the query results into new DataTable.
DataTable table = query.CopyToDataTable();

List<YourModel> data = new List<YourModel>();
DataTable dataTable = Newtonsoft.Json.JsonConvert.DeserializeObject<DataTable>(Newtonsoft.Json.JsonConvert.SerializeObject(data));

public DataTable ConvertToDataTable<T>(IList<T> data)
{
PropertyDescriptorCollection properties =
TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
foreach (PropertyDescriptor prop in properties)
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
foreach (T item in data)
{
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
{
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
}
table.Rows.Add(row);
}
return table;
}

try this
public static DataTable ListToDataTable<T>(IList<T> lst)
{
currentDT = CreateTable<T>();
Type entType = typeof(T);
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entType);
foreach (T item in lst)
{
DataRow row = currentDT.NewRow();
foreach (PropertyDescriptor prop in properties)
{
if (prop.PropertyType == typeof(Nullable<decimal>) || prop.PropertyType == typeof(Nullable<int>) || prop.PropertyType == typeof(Nullable<Int64>))
{
if (prop.GetValue(item) == null)
row[prop.Name] = 0;
else
row[prop.Name] = prop.GetValue(item);
}
else
row[prop.Name] = prop.GetValue(item);
}
currentDT.Rows.Add(row);
}
return currentDT;
}
public static DataTable CreateTable<T>()
{
Type entType = typeof(T);
DataTable tbl = new DataTable(DTName);
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(entType);
foreach (PropertyDescriptor prop in properties)
{
if (prop.PropertyType == typeof(Nullable<decimal>))
tbl.Columns.Add(prop.Name, typeof(decimal));
else if (prop.PropertyType == typeof(Nullable<int>))
tbl.Columns.Add(prop.Name, typeof(int));
else if (prop.PropertyType == typeof(Nullable<Int64>))
tbl.Columns.Add(prop.Name, typeof(Int64));
else
tbl.Columns.Add(prop.Name, prop.PropertyType);
}
return tbl;
}

It's also possible through XmlSerialization.
The idea is - serialize to `XML` and then `readXml` method of `DataSet`.
I use this code (from an answer in SO, forgot where)
public static string SerializeXml<T>(T value) where T : class
{
if (value == null)
{
return null;
}
XmlSerializer serializer = new XmlSerializer(typeof(T));
XmlWriterSettings settings = new XmlWriterSettings();
settings.Encoding = new UnicodeEncoding(false, false);
settings.Indent = false;
settings.OmitXmlDeclaration = false;
// no BOM in a .NET string
using (StringWriter textWriter = new StringWriter())
{
using (XmlWriter xmlWriter = XmlWriter.Create(textWriter, settings))
{
serializer.Serialize(xmlWriter, value);
}
return textWriter.ToString();
}
}
so then it's as simple as:
string xmlString = Utility.SerializeXml(trans.InnerList);
DataSet ds = new DataSet("New_DataSet");
using (XmlReader reader = XmlReader.Create(new StringReader(xmlString)))
{
ds.Locale = System.Threading.Thread.CurrentThread.CurrentCulture;
ds.ReadXml(reader);
}
Not sure how it stands against all the other answers to this post, but it's also a possibility.

Marc Gravell's answer but in VB.NET
Public Shared Function ToDataTable(Of T)(data As IList(Of T)) As DataTable
Dim props As PropertyDescriptorCollection = TypeDescriptor.GetProperties(GetType(T))
Dim table As New DataTable()
For i As Integer = 0 To props.Count - 1
Dim prop As PropertyDescriptor = props(i)
table.Columns.Add(prop.Name, prop.PropertyType)
Next
Dim values As Object() = New Object(props.Count - 1) {}
For Each item As T In data
For i As Integer = 0 To values.Length - 1
values(i) = props(i).GetValue(item)
Next
table.Rows.Add(values)
Next
Return table
End Function

To Convert Generic list into DataTable
using Newtonsoft.Json;
public DataTable GenericToDataTable(IList<T> list)
{
var json = JsonConvert.SerializeObject(list);
DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));
return dt;
}

I've written a small library myself to accomplish this task. It uses reflection only for the first time an object type is to be translated to a datatable. It emits a method that will do all the work translating an object type.
Its blazing fast. You can find it here:
ToDataTable() in MoreLinq on GitHub
original: ModelShredder on GoogleCode, was merged into MoreLinq, which moved from GoogleCode to GitHub

A 2019 answer if you're using .NET Core - use the Nuget ToDataTable library. Advantages:
Better performance than FastMember
Also creates structured SqlParameters for use as SQL Server Table-Valued Parameters
Disclaimer - I'm the author of ToDataTable
Performance - I span up some Benchmark .Net tests and included them in the ToDataTable repo. The results were as follows:
Creating a 100,000 Row Datatable:
MacOS Windows
Reflection 818.5 ms 818.3 ms
FastMember from 1105.5 ms 976.4 ms
Mark's answer
Improved FastMember 524.6 ms 456.4 ms
ToDataTable 449.0 ms 376.5 ms
The FastMember method suggested in Marc's answer seemed to perform worse than Mary's answer which used reflection, but I rolled another method using a FastMember TypeAccessor and it performed much better. Nevertheless the ToDataTable package outperformed the lot.

I also had to come up with an alternate solution, as none of the options listed here worked in my case. I was using an IEnumerable which returned an IEnumerable and the properties couldn't be enumerated. This did the trick:
// remove "this" if not on C# 3.0 / .NET 3.5
public static DataTable ConvertToDataTable<T>(this IEnumerable<T> data)
{
List<IDataRecord> list = data.Cast<IDataRecord>().ToList();
PropertyDescriptorCollection props = null;
DataTable table = new DataTable();
if (list != null && list.Count > 0)
{
props = TypeDescriptor.GetProperties(list[0]);
for (int i = 0; i < props.Count; i++)
{
PropertyDescriptor prop = props[i];
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
}
}
if (props != null)
{
object[] values = new object[props.Count];
foreach (T item in data)
{
for (int i = 0; i < values.Length; i++)
{
values[i] = props[i].GetValue(item) ?? DBNull.Value;
}
table.Rows.Add(values);
}
}
return table;
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.ComponentModel;
public partial class Default3 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
DataTable dt = new DataTable();
dt = lstEmployee.ConvertToDataTable();
}
public static DataTable ConvertToDataTable<T>(IList<T> list) where T : class
{
try
{
DataTable table = CreateDataTable<T>();
Type objType = typeof(T);
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(objType);
foreach (T item in list)
{
DataRow row = table.NewRow();
foreach (PropertyDescriptor property in properties)
{
if (!CanUseType(property.PropertyType)) continue;
row[property.Name] = property.GetValue(item) ?? DBNull.Value;
}
table.Rows.Add(row);
}
return table;
}
catch (DataException ex)
{
return null;
}
catch (Exception ex)
{
return null;
}
}
private static DataTable CreateDataTable<T>() where T : class
{
Type objType = typeof(T);
DataTable table = new DataTable(objType.Name);
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(objType);
foreach (PropertyDescriptor property in properties)
{
Type propertyType = property.PropertyType;
if (!CanUseType(propertyType)) continue;
//nullables must use underlying types
if (propertyType.IsGenericType && propertyType.GetGenericTypeDefinition() == typeof(Nullable<>))
propertyType = Nullable.GetUnderlyingType(propertyType);
//enums also need special treatment
if (propertyType.IsEnum)
propertyType = Enum.GetUnderlyingType(propertyType);
table.Columns.Add(property.Name, propertyType);
}
return table;
}
private static bool CanUseType(Type propertyType)
{
//only strings and value types
if (propertyType.IsArray) return false;
if (!propertyType.IsValueType && propertyType != typeof(string)) return false;
return true;
}
}

I realize that this has been closed for a while; however, I had a solution to this specific problem but needed a slight twist: the columns and data table needed to be predefined / already instantiated. Then I needed to simply insert the types into the data table.
So here's an example of what I did:
public static class Test
{
public static void Main()
{
var dataTable = new System.Data.DataTable(Guid.NewGuid().ToString());
var columnCode = new DataColumn("Code");
var columnLength = new DataColumn("Length");
var columnProduct = new DataColumn("Product");
dataTable.Columns.AddRange(new DataColumn[]
{
columnCode,
columnLength,
columnProduct
});
var item = new List<SomeClass>();
item.Select(data => new
{
data.Id,
data.Name,
data.SomeValue
}).AddToDataTable(dataTable);
}
}
static class Extensions
{
public static void AddToDataTable<T>(this IEnumerable<T> enumerable, System.Data.DataTable table)
{
if (enumerable.FirstOrDefault() == null)
{
table.Rows.Add(new[] {string.Empty});
return;
}
var properties = enumerable.FirstOrDefault().GetType().GetProperties();
foreach (var item in enumerable)
{
var row = table.NewRow();
foreach (var property in properties)
{
row[property.Name] = item.GetType().InvokeMember(property.Name, BindingFlags.GetProperty, null, item, null);
}
table.Rows.Add(row);
}
}
}

private DataTable CreateDataTable(IList<T> item)
{
Type type = typeof(T);
var properties = type.GetProperties();
DataTable dataTable = new DataTable();
foreach (PropertyInfo info in properties)
{
dataTable.Columns.Add(new DataColumn(info.Name, Nullable.GetUnderlyingType(info.PropertyType) ?? info.PropertyType));
}
foreach (T entity in item)
{
object[] values = new object[properties.Length];
for (int i = 0; i < properties.Length; i++)
{
values[i] = properties[i].GetValue(entity);
}
dataTable.Rows.Add(values);
}
return dataTable;
}

If you are using VB.NET then this class does the job.
Imports System.Reflection
''' <summary>
''' Convert any List(Of T) to a DataTable with correct column types and converts Nullable Type values to DBNull
''' </summary>
Public Class ConvertListToDataset
Public Function ListToDataset(Of T)(ByVal list As IList(Of T)) As DataTable
Dim dt As New DataTable()
'/* Create the DataTable columns */
For Each pi As PropertyInfo In GetType(T).GetProperties()
If pi.PropertyType.IsValueType Then
Debug.Print(pi.Name)
End If
If IsNothing(Nullable.GetUnderlyingType(pi.PropertyType)) Then
dt.Columns.Add(pi.Name, pi.PropertyType)
Else
dt.Columns.Add(pi.Name, Nullable.GetUnderlyingType(pi.PropertyType))
End If
Next
'/* Populate the DataTable with the values in the Items in List */
For Each item As T In list
Dim dr As DataRow = dt.NewRow()
For Each pi As PropertyInfo In GetType(T).GetProperties()
dr(pi.Name) = IIf(IsNothing(pi.GetValue(item)), DBNull.Value, pi.GetValue(item))
Next
dt.Rows.Add(dr)
Next
Return dt
End Function
End Class

if you have properties in your class this line of code is OK !!
PropertyDescriptorCollection props =
TypeDescriptor.GetProperties(typeof(T));
but if you have all public fields then use this:
public static DataTable ToDataTable<T>( IList<T> data)
{
FieldInfo[] myFieldInfo;
Type myType = typeof(T);
// Get the type and fields of FieldInfoClass.
myFieldInfo = myType.GetFields(BindingFlags.NonPublic | BindingFlags.Instance
| BindingFlags.Public);
DataTable dt = new DataTable();
for (int i = 0; i < myFieldInfo.Length; i++)
{
FieldInfo property = myFieldInfo[i];
dt.Columns.Add(property.Name, property.FieldType);
}
object[] values = new object[myFieldInfo.Length];
foreach (T item in data)
{
for (int i = 0; i < values.Length; i++)
{
values[i] = myFieldInfo[i].GetValue(item);
}
dt.Rows.Add(values);
}
return dt;
}
the original answer is from above , I just edited to use fields instead of properties
and to use it do this
DataTable dt = new DataTable();
dt = ToDataTable(myBriefs);
gridData.DataSource = dt;
gridData.DataBind();

To convert a generic list to data table, you could use the DataTableGenerator
This library lets you convert your list into a data table with multi-feature like
Translate data table header
specify some column to show

You can try something like below
public static DataTable GetDataTableFromObjects(object[] objects)
{
if (objects != null && objects.Length > 0)
{
Type t = objects[0].GetType();
DataTable dt = new DataTable(t.Name);
foreach (PropertyInfo pi in t.GetProperties())
{
dt.Columns.Add(new DataColumn(pi.Name));
}
foreach (var o in objects)
{
DataRow dr = dt.NewRow();
foreach (DataColumn dc in dt.Columns)
{
dr[dc.ColumnName] = o.GetType().GetProperty(dc.ColumnName).GetValue(o, null);
}
dt.Rows.Add(dr);
}
return dt;
}
return null;
}

This is the simple Console Application to convert List to Datatable.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.ComponentModel;
namespace ConvertListToDataTable
{
public static class Program
{
public static void Main(string[] args)
{
List<MyObject> list = new List<MyObject>();
for (int i = 0; i < 5; i++)
{
list.Add(new MyObject { Sno = i, Name = i.ToString() + "-KarthiK", Dat = DateTime.Now.AddSeconds(i) });
}
DataTable dt = ConvertListToDataTable(list);
foreach (DataRow row in dt.Rows)
{
Console.WriteLine();
for (int x = 0; x < dt.Columns.Count; x++)
{
Console.Write(row[x].ToString() + " ");
}
}
Console.ReadLine();
}
public class MyObject
{
public int Sno { get; set; }
public string Name { get; set; }
public DateTime Dat { get; set; }
}
public static DataTable ConvertListToDataTable<T>(this List<T> iList)
{
DataTable dataTable = new DataTable();
PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
for (int i = 0; i < props.Count; i++)
{
PropertyDescriptor propertyDescriptor = props[i];
Type type = propertyDescriptor.PropertyType;
if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
type = Nullable.GetUnderlyingType(type);
dataTable.Columns.Add(propertyDescriptor.Name, type);
}
object[] values = new object[props.Count];
foreach (T iListItem in iList)
{
for (int i = 0; i < values.Length; i++)
{
values[i] = props[i].GetValue(iListItem);
}
dataTable.Rows.Add(values);
}
return dataTable;
}
}
}

Dim counties As New List(Of County)
Dim dtCounties As DataTable
dtCounties = _combinedRefRepository.Get_Counties()
If dtCounties.Rows.Count <> 0 Then
For Each row As DataRow In dtCounties.Rows
Dim county As New County
county.CountyId = row.Item(0).ToString()
county.CountyName = row.Item(1).ToString().ToUpper()
counties.Add(county)
Next
dtCounties.Dispose()
End If

I think it's more convenient and easy to use.
List<Whatever> _lobj= new List<Whatever>();
var json = JsonConvert.SerializeObject(_lobj);
DataTable dt = (DataTable)JsonConvert.DeserializeObject(json, (typeof(DataTable)));

If you want to use reflection and set columns order/ include only some columns/ Exclude some columns try this:
private static DataTable ConvertToDataTable<T>(IList<T> data, string[] fieldsToInclude = null,
string[] fieldsToExclude = null)
{
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
DataTable table = new DataTable();
foreach (PropertyDescriptor prop in properties)
{
if ((fieldsToInclude != null && !fieldsToInclude.Contains(prop.Name)) ||
(fieldsToExclude != null && fieldsToExclude.Contains(prop.Name)))
continue;
table.Columns.Add(prop.Name, Nullable.GetUnderlyingType(prop.PropertyType) ?? prop.PropertyType);
}
foreach (T item in data)
{
var atLeastOnePropertyExists = false;
DataRow row = table.NewRow();
foreach (PropertyDescriptor prop in properties)
{
if ((fieldsToInclude != null && !fieldsToInclude.Contains(prop.Name)) ||
(fieldsToExclude != null && fieldsToExclude.Contains(prop.Name)))
continue;
row[prop.Name] = prop.GetValue(item) ?? DBNull.Value;
atLeastOnePropertyExists = true;
}
if(atLeastOnePropertyExists) table.Rows.Add(row);
}
if (fieldsToInclude != null)
SetColumnsOrder(table, fieldsToInclude);
return table;
}
private static void SetColumnsOrder(DataTable table, params String[] columnNames)
{
int columnIndex = 0;
foreach (var columnName in columnNames)
{
table.Columns[columnName].SetOrdinal(columnIndex);
columnIndex++;
}
}

List<object> Basket;
string json = JsonConvert.SerializeObject(Basket, Formatting.Indented);
DataTable dtUsingMethod = Business.GetJSONToDataTableUsingNewtonSoftDll(json);
public static DataTable GetJSONToDataTableUsingNewtonSoftDll(string JSONData)
{
DataTable dt = (DataTable)JsonConvert.DeserializeObject(JSONData, (typeof(DataTable)));
return dt;
}

Here is another one to the list. Cinchoo ETL - an open source library to convert enumerable to datatable.
List<Whatever> whatever = new List<Whatever>();
var dt = whatever.AsDataTable();
Disclaimer: I'm author of this library.

Develop Reference

C# (C-Sharp) is a programming language developed by Microsoft that runs on the .NET Framework.

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