Basically I'd like to use a LINQ statement for an sql like %. I thought .Contains would be appropriate but I don't get the right result.
I have a model:
public class Model {
public string Number { get; set; }
}
Inside my function:
private List<Model> getSearchResults(List<Model> models)
{
List<Model> result = models.Where(m => m.Number.Contains("3330")).ToList();
return result;
}
Inside my models list is definitively an entry with number 3330, but the returned result is empty. :(
This should also work with .Contains("333"). But it doesn't.
I suspect you're actually using the linq-to-sql provider.
If that's the case, then you should use SqlMethods.Like instead of String.Contains:
list.Where(l => SqlMethods.Like(l.Number, "%12%")).ToList();
Contains statements should be used like sql operator 'IN'. See the link for details:
tip-8-writing-where-in-style-queries-using-linq-to-entities
I think you are looking for something like this:
how-to-do-sql-like-in-linq
You should use like this:
List<Model> result = models.Where(m => m.Number.Contains("/3330/")).ToList();
You can also use .StartsWith() or .EndsWith()
Ok, here is my sample of code for you issue, and yes, the Contains method certainly does work:
using System;
using System.Linq;
using System.Collections.Generic;
public class Program
{
public class Model {
public string Number { get; set; }
}
private static List<Model> getSearchResults(List<Model> models)
{
List<Model> result = models.Where(m => m.Number.Contains("3330")).ToList();
return result;
}
public static void Main()
{
List<Model> list = new List<Model>() {
new Model() { Number = "13330A"},
new Model() { Number = "13230A"},
new Model() { Number = "3330A"},
new Model() { Number = "543330"},
new Model() { Number = "48913"},
new Model() { Number = "97798133"},
new Model() { Number = "542130"}
};
foreach(Model v in getSearchResults(list)) {
Console.WriteLine(v.Number);
}
}
}
and output is:
13330A
3330A
543330
Check your code, you can play with this example on http://dotnetfiddle.net/143UgC
Related
Here i have a class:
public class AccessinfoDetails
{
public IEnumerable<TurbineDvce> Devices { get; set; }
public TixiModem TixiModem { get; set; }
}
i have an interface which i defined like this:
public IQueryable<AccessinfoDetails> Devices(string id);
for the implemntation of the interface:
public IQueryable<AccessinfoDetails> Devices(string id){
AccessinfoDetails result = new AccessinfoDetails()
{
Devices = distinct,
TixiModem = tixiModem
};
return result;}
but i get an error saying it can not convert AcessInfoDeatils to system.linq.iquerable
which is right,but how can i fix it and is it a right way to pass data to my API controller?
This should work, change your return line to look like this:
return new [] {result}.AsQuerable();
or as Rufus L points out in the comments a typed version using list instead of array:
return new List<AccessinfoDetails> { result }.AsQueryable();
The return type of the method is IQueryable <AccessinfoDetails>, it is a data collection, but the "result" in the method is a single data of type AccessinfoDetails.Not clear about your scenario.
If you don't want to change the return type of the method, you should change the method as shown:
public IQueryable<AccessinfoDetails> Devices(string id)
{
List<AccessinfoDetails> list = new List<AccessinfoDetails>()
{
new AccessinfoDetails
{
Devices = distinct,
ixiModem = tixiModem
}
};
return list.AsQueryable();
}
I have table called Asset. It has lot of columns. I only want to select two of them and use them separately.
Both of these columns are strings.
Linq query :
public static List<string> GetAssetIdsWithNames()
{
using (var db = DbManager.Get())
{
var result = db.Assets.SelectMany(i=> new[] { i.AssetName, i.AssetId }).Distinct().ToList();
return result;
}
}
Where I want to use them :
var assetList = AssetManager.GetAssetIdsWithNames();
//CURRENCYBOX IS A DROPDOWN
CurrencyBox.DataSource = assetList;
CurrencyBox.DataBind();
foreach (var item in assetList)
{
CurrencyBox.DataValueField = //asset id goes here
CurrencyBox.DataTextField =//asset name goes here
break;
}
You cannot access the anonymous type outside of the local scope.
Anonymous types can only be returned as Object outside their local scope and their properties inspected via reflection.
So in this scenario, you are likely better off to use a typed data contract and map from your Asset entity instead and then access it from your calling method.
Your use of SelectMany seems odd too, you probably are after Select instead.
public class AssetDto
{
public string Name { get;set; }
public string Id { get; set; }
}
public static List<AssetDto> GetAssetIdsWithNames()
{
using (var db = DbManager.Get())
{
var result = db.Assets.Select(i=> new AssetDto { Name = i.AssetName, Id = i.AssetId }).ToList();
return result;
}
}
You could use named value tuples for that so you don't need to create an extra class
public static List<(string Name, int Id)> GetAssetWithIds()
{
using (var db = DbManager.Get())
{
var result = db.Assets
.Select(a => new { a.AssetName, a.AssetId })
.Distinct().AsEnumerable()
.Select(a => (a.AssetName, a.AssetId))
.ToList();
return result;
}
}
You will need to add System.ValueTuple
I have this class
public class BlessingDTO
{
public List<string> BlessingCategoryName;
public List<string> Blessings;
}
I am Getting the response of the two lists this way:
public async Task<List<BlessingDTO>> GetBlessing(string UserType)
{
string blessing = "Blessing_" + UserType;
List<BlessingDTO> results = new List<BlessingDTO>();
using (DTS_OnlineContext context = new DTS_OnlineContext())
{
var items = await context.Messages.AsNoTracking().Where(x => x.MessageContext == blessing).GroupBy(x=>x.GroupKey).Select(b=>b.OrderBy(x=>x.Sort)).ToListAsync();
if (items.Count() > 0)
{//Notes.Select(x => x.Author).Distinct();
results = items.ToList().ConvertAll(x => new BlessingDTO()
{ BlessingCategoryName = x.ToList().Select(y => y.MessageName).Distinct().ToList(),
Blessings = x.ToList().Select(y => y.MessageText).ToList()
});
}
}
return results;
}
if I am changing the class, for my porpuse to be:
public class BlessingDTO
{
public List<string> BlessingCategoryName;
public List<bless> Blessings;
}
public class bless
{
public string text;
public int length;
}
how can I initialize the new class ?
Blessings = new bless
won't give the results. how can I save the data to bring them in the response
Let's focus in this part:
items
.ToList()
.ConvertAll(x =>
new BlessingDTO()
{
BlessingCategoryName = x.ToList().Select(y => y.MessageName).Distinct().ToList(),
Blessings = x.ToList().Select(y => y.MessageText).ToList()
}
);
where items is probably a List<List<Message>>, thus x being a List<Message>.
Now what is causing an error is the following: Blessings = x.ToList().Select(y => y.MessageText).ToList(). This creates a new list for the list of messages, then selects the MessageText from that list, which results in IEnumerable<string>. In the end a new list is created for these strings. This list of strings isn't assignable to List<bless>, thus will generate an error.
What you want is a result of List<bless>, so we need to convert the List<Message> list into a List<bless> somehow. We know how to do that, namely with a select: x.Select(message => new bless()).ToList(). All we have to do is fill in the properties of bless: x.Select(message => new bless { text = message.MessageText }).ToList(). The other property is up to you.
You can initialise the list like this:
public class BlessingDTO
{
public List<string> BlessingCategoryName;
public List<bless> Blessings = new List<bless>();
}
Although, I would recommend these fields are changes to properties, as that is more idiomatic in C#
public class BlessingDTO
{
public List<string> BlessingCategoryName {get;set;}
public List<bless> Blessings {get;set;} = new List<bless>();
}
I have the following:
public class Broadcast {
public int NumUsersToMessage { get; set; }
public int NumMessagesQueued { get; set; }
public string DbUsersMessaged { get; set; }
public int NumMessagesSent {
get {
return UsersMessaged.Count();
}
}
public List<int> UsersMessaged {
get {
return DbUsersMessaged == null ? new List<int>() : DbUsersMessaged.Split(',').Select(Int32.Parse).ToList();
}
set {
DbUsersMessaged = value != null ? String.Join(",", value) : null;
}
}
}
My goal here is to only ever access DbUsersMessaged through UsersMessaged. I'm attempting to do broadcast.UsersMessaged.Add(2), however since this is not an assignment, I can't get the property to behave as I like. Instead, I have to do this:
tempList = broadcast.UsersMessaged();
tempList.Add(2);
broadcast.UsersMessaged = tempList;
db.SaveChanges();
Which is obviously unwieldy. I'm considering making an AddReassign extension method but I want to know - what's the standard practice here for supporting Lists of primitive types? It looks like even with the extension method, my best shot looks like this:
broadcast.UsersMessaged = broadcast.UsersMessaged.AddReassign(2) // yuck!
Before anyone asks - we've intentionally denormalized this for performance reasons.
If you don't care about performance, you can create own list:
public class MyList : IList<int>
{
private List<int> underlyingList;
private Broadcast entity;
public MyList(Broadcast entity)
{
this.entity = entity;
this.underlyingList = entity.DbUsersMessaged?.Split(",") ?? new List<int>();
}
public void Add(int i)
{
this.underlyingList.Add(i);
this.entity.DbUsersMessaged = String.Join(",", underylingList);
}
// other interface memebers impl
}
Then
MyList list;
public IList<int> UsersMessaged {
get {
return myList ?? (myList = new MyList(this));
}
}
Of course it is only sample.
I recommend you to have a look at this: Entity Framework 5 - Looking for Central Point to Execute Custom Code after Entity is Loaded from Database
And then convert from string to list, and then use Saving Changes event to convert back into the string construction when saving.
Then, for performance, maybe you want to use byte[] rather than a string for storing the data in the database.
This is all in C#, using .NET 2.0.
I have two lists of objects. They are not related objects, but they do have certain things in common that can be compared, such as a GUID-based unique identifier. These two lists need to be filtered by another list which just contains GUIDs which may or may not match up with the IDs contained in the first two lists.
I have thought about the idea of casting each object list to just object and sorting by that, but I'm not sure that I'll be able to access the ID property once it's cast, and I'm thinking that the method to sort the two lists should be somewhat dumb in knowing what the list to be sorted is.
What would be the best way to bring in each object list so that it can be sorted against the list with only the IDs?
You should make each of your different objects implement a common interface. Then create an IComparer<T> for that interface and use it in your sort.
Okay, if you have access to modify your original classes only to add the interface there, Matthew had it spot on. I went a little crazy here and defined out a full solution using 2.0 anonymous delegates. (I think I'm way addicted to 3.0 Lambda; otherwise, I probably would've written this out in foreach loops if I was using 2005 still).
Basically, create an interface with the common properties. Make yoru two classes implement the interface. Create a common list casted as the interface, cast and rip the values into the new list; remove any unmatched items.
//Program Output:
List1:
206aa77c-8259-428b-a4a0-0e005d8b016c
64f71cc9-596d-4cb8-9eb3-35da3b96f583
List2:
10382452-a7fe-4307-ae4c-41580dc69146
97f3f3f6-6e64-4109-9737-cb72280bc112
64f71cc9-596d-4cb8-9eb3-35da3b96f583
Matches:
64f71cc9-596d-4cb8-9eb3-35da3b96f583
Press any key to continue . . .
using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApplication8
{
class Program
{
static void Main(string[] args)
{
//test initialization
List<ClassTypeA> list1 = new List<ClassTypeA>();
List<ClassTypeB> list2 = new List<ClassTypeB>();
ClassTypeA citem = new ClassTypeA();
ClassTypeB citem2 = new ClassTypeB();
citem2.ID = citem.ID;
list1.Add(new ClassTypeA());
list1.Add(citem);
list2.Add(new ClassTypeB());
list2.Add(new ClassTypeB());
list2.Add(citem2);
//new common list.
List<ICommonTypeMakeUpYourOwnName> common_list =
new List<ICommonTypeMakeUpYourOwnName>();
//in english, give me everything in list 1
//and cast it to the interface
common_list.AddRange(
list1.ConvertAll<ICommonTypeMakeUpYourOwnName>(delegate(
ClassTypeA x) { return (ICommonTypeMakeUpYourOwnName)x; }));
//in english, give me all the items in the
//common list that don't exist in list2 and remove them.
common_list.RemoveAll(delegate(ICommonTypeMakeUpYourOwnName x)
{ return list2.Find(delegate(ClassTypeB y)
{return y.ID == x.ID;}) == null; });
//show list1
Console.WriteLine("List1:");
foreach (ClassTypeA item in list1)
{
Console.WriteLine(item.ID);
}
//show list2
Console.WriteLine("\nList2:");
foreach (ClassTypeB item in list2)
{
Console.WriteLine(item.ID);
}
//show the common items
Console.WriteLine("\nMatches:");
foreach (ICommonTypeMakeUpYourOwnName item in common_list)
{
Console.WriteLine(item.ID);
}
}
}
interface ICommonTypeMakeUpYourOwnName
{
Guid ID { get; set; }
}
class ClassTypeA : ICommonTypeMakeUpYourOwnName
{
Guid _ID;
public Guid ID {get { return _ID; } set { _ID = value;}}
int _Stuff1;
public int Stuff1 {get { return _Stuff1; } set { _Stuff1 = value;}}
string _Stuff2;
public string Stuff2 {get { return _Stuff2; } set { _Stuff2 = value;}}
public ClassTypeA()
{
this.ID = Guid.NewGuid();
}
}
class ClassTypeB : ICommonTypeMakeUpYourOwnName
{
Guid _ID;
public Guid ID {get { return _ID; } set { _ID = value;}}
int _Stuff3;
public int Stuff3 {get { return _Stuff3; } set { _Stuff3 = value;}}
string _Stuff4;
public string Stuff4 {get { return _Stuff4; } set { _Stuff4 = value;}}
public ClassTypeB()
{
this.ID = Guid.NewGuid();
}
}
}
Using only .NET 2.0 methods:
class Foo
{
public Guid Guid { get; }
}
List<Foo> GetFooSubset(List<Foo> foos, List<Guid> guids)
{
return foos.FindAll(foo => guids.Contains(foo.Guid));
}
If your classes don't implement a common interface, you'll have to implement GetFooSubset for each type individually.
I'm not sure that I fully understand what you want, but you can use linq to select out the matching items from the lists as well as sorting them. Here is a simple example where the values from one list are filtered on another and sorted.
List<int> itemList = new List<int>() { 9,6,3,4,5,2,7,8,1 };
List<int> filterList = new List<int>() { 2, 6, 9 };
IEnumerable<int> filtered = itemList.SelectMany(item => filterList.Where(filter => filter == item)).OrderBy(p => p);
I haven't had a chance to use AutoMapper yet, but from what you describe you wish to check it out. From Jimmy Bogard's post:
AutoMapper conventions
Since AutoMapper flattens, it will
look for:
Matching property names
Nested property names (Product.Name
maps to ProductName, by assuming a
PascalCase naming convention)
Methods starting with the word “Get”,
so GetTotal() maps to Total
Any existing type map already
configured
Basically, if you removed all the
“dots” and “Gets”, AutoMapper will
match property names. Right now,
AutoMapper does not fail on mismatched
types, but for some other reasons.
I am not totally sure what you want as your end results, however....
If you are comparing the properties on two different types you could project the property names and corresponding values into two dictionaries. And with that information do some sort of sorting/difference of the property values.
Guid newGuid = Guid.NewGuid();
var classA = new ClassA{Id = newGuid};
var classB = new ClassB{Id = newGuid};
PropertyInfo[] classAProperties = classA.GetType().GetProperties();
Dictionary<string, object> classAPropertyValue = classAProperties.ToDictionary(pName => pName.Name,
pValue =>
pValue.GetValue(classA, null));
PropertyInfo[] classBProperties = classB.GetType().GetProperties();
Dictionary<string, object> classBPropetyValue = classBProperties.ToDictionary(pName => pName.Name,
pValue =>
pValue.GetValue(classB, null));
internal class ClassB
{
public Guid Id { get; set; }
}
internal class ClassA
{
public Guid Id { get; set; }
}
classAPropertyValue
Count = 1
[0]: {[Id, d0093d33-a59b-4537-bde9-67db324cf7f6]}
classBPropetyValue
Count = 1
[0]: {[Id, d0093d33-a59b-4537-bde9-67db324cf7f6]}
Thist should essentially get you what you want - but you may be better of using linq
class T1
{
public T1(Guid g, string n) { Guid = g; MyName = n; }
public Guid Guid { get; set; }
public string MyName { get; set; }
}
class T2
{
public T2(Guid g, string n) { ID = g; Name = n; }
public Guid ID { get; set; }
public string Name { get; set; }
}
class Test
{
public void Run()
{
Guid G1 = Guid.NewGuid();
Guid G2 = Guid.NewGuid();
Guid G3 = Guid.NewGuid();
List<T1> t1s = new List<T1>() {
new T1(G1, "one"),
new T1(G2, "two"),
new T1(G3, "three")
};
List<Guid> filter = new List<Guid>() { G2, G3};
List<T1> filteredValues1 = t1s.FindAll(delegate(T1 item)
{
return filter.Contains(item.Guid);
});
List<T1> filteredValues2 = t1s.FindAll(o1 => filter.Contains(o1.Guid));
}
}