Develop Reference

How to cast a dynamic object to a type and compare

I have a model called products,
public class Product
{
public string Name { get; set; }
public string Sku { get; set; }
public float Cost { get; set; }
public string Description { get; set; }
}
I will get a list of objects as type dynamic from externel source as follows
string query = "SELECT Id,Name,KNDYCPQ__Description__c,KNDYCPQ__ProductCode__c FROM KNDY4__Product__c";
List<dynamic> products = new List<dynamic>();
products = await SalesforceSyncProvider.QueryAsync(query);
foreach (var x in products)
{
Product product = new Product();
if (db.Products.Where(a => a.Sku ==x.KNDYCPQ__ProductCode__c).FirstOrDefault() != null) {
product.Name = x.Name;
product.Sku = x.KNDYCPQ__ProductCode__c;
product.Description = x.KNDYCPQ__Description__c;
product.Cost = 2000;
db.Products.Add(product);
}
}
So, before adding to my db, I want to check the product code (KNDYCPQ__ProductCode__c) with my Sku for avoiding duplicates but the if condition is failing and showing the error that, an expression tree may not contain a dynamic operation.

Put x.KNDYCPQ__ProductCode__c in a strongly typed variable and use that in the expression.
string sku = x.KNDYCPQ__ProductCode__c;
if (db.Products.Where(a => a.Sku == sku).FirstOrDefault() != null) {
//...

using linq and c# to create a nested list object from a flat list object

I have a question. It's about linq in combination with c#.
I want to create a tree structure from a flatten structure in a pre defined object structure.
The following code which I've got work, but both are not exactly what i want.
In linq:
var result = listAgenderingen.GroupBy(records => records.Agnnummer)
.Select(group => new { AgnNummer = group.Key, Items = group.ToList()}).ToList();
the issue is that this does not result in the object I want.
So I've rewritten this to the following code
List<string> test = listAgenderingen.Select(x => x.Agnnummer).Distinct().ToList();
foreach (var item in test)
{
List<Agendering> listAgendering = listAgenderingen.Where(agend => agend.Agnnummer == item).OrderBy(ord => ord.Agnnummer).ToList();
AgnAgendering AgnAgendering = new AgnAgendering() {AgnNummer =item, Agenderingen = listAgendering };
}
this code actually works correct. but for 200000 records, it's taking a lot of time while the original linq takes a few seconds.
my question is can the linq be rewritten so it will create or convert to the richt object?
the structure of the classes:
public class Agendering
{
public int AgnID { get; set; }
public string Agnnummer { get; set; }
}
public class AgnAgendering
{
public string AgnNummer { get; set; }
public List<Agendering> Agenderingen { get; set; }
}
I hope someone has a sollution.

If I understand correctly, you want:
var result = listAgenderingen.GroupBy(records => records.Agnnummer)
.Select(group => new AgnAgendering { AgnNummer = group.Key, Agenderingen = group.ToList()}).ToList();

Your properties naming makes it absolutely unreadable and unclear.
Assuming that you have a flat structure like:
public class Item
{
public int ID { get; set; }
public int? ParentID { get; set; }
}
and you want a tree-like structure:
public class TreeItem
{
public int ID { get; set; }
public TreeItem Parent { get; set; }
public List<TreeItem> Children { get; set; }
public TreeItem(int id)
{
ID = id;
Children = new List<TreeItem>();
}
public TreeItem(int id, TreeItem parent) : this(id)
{
Parent = parent;
}
}
You can do most optimally in O(n) using Dictionary:
Item[] items = ...;
Dictionary<int, TreeItem> result = new Dictionary<int, TreeItem>();
foreach (var item in items.OrderBy(x => x.ParentID ?? -1))
{
TreeItem current;
if (item.ParentID.HasValue)
{
TreeItem parent = result[item.ParentID]; // guaranteed to exist due to order
current = new TreeItem(item.ID, parent);
parent.Children.Add(current);
} else {
current = new TreeItem(item.ID);
}
}
TreeItem[] treeItems = result.Values.ToArray();

Get all properties from a view model to display in array

I have a view model that have a lot of properties, and I created a custom attribute for send the data to hubspot, because hubspot need a specific nomenclature, then I need to create a method that have some king of iterator, that for every property that contain my custom attribute he put a specific output, here is the code:
public class CreateTrialUserHubspotViewModel {
[HubspotAttribute("firstname")]
[Display(Name = "First Name")]
[StringLength(50)]
[Required]
public string FirstName { get; set; }
[HubspotAttribute("lastname")]
[Display(Name = "Last Name")]
[StringLength(50)]
[Required]
public string LastName { get; set; }
[HubspotAttribute("jobtitle")]
[Display(Name = "Job title")]
[StringLength(50)]
[Required]
public string JobTitle { get; set; }
}
Now this is my custom attribute
[AttributeUsage(AttributeTargets.All)]
public class HubspotAttribute : System.Attribute {
public readonly string hubspotValue;
public HubspotAttribute(string value)
{
this.hubspotValue = value;
}
}
And then I need to create a method that take a viewmodel object and create my output, I need some suggest about how to do that, will be something like this:
private static RowValidation ValidateRowWithManifest<T>(CreateTrialUserHubspotViewModel trialUser) {
RowValidation validation = new RowValidation();
FieldInfo[] fields = typeof(T).GetPropertiesOfSomeWay;
foreach (DataType field in fields) {
output+=whatINeed
}
return validation;
}
}
The needed output will be like: [firstname:"pepe", lastname="perez", jobtitle"none"]. just calling that method will return all the data I need.

public string GetString<T>(T #object)
{
var output = new StringBuilder();
var type = typeof(T);
var properties = type.GetProperties();
foreach (var property in properties)
{
var attributes = property.GetCustomAttributes(typeof(HubspotAttribute), true);
if (attributes.Length == 0)
continue;
var name = ((HubspotAttribute)attributes[0]).hubspotValue;
var value = property.GetValue(#object) ?? "none";
output.AppendFormat("{0}:\"{1}\",", name, value);
}
var fields = output.ToString().TrimEnd(',');
return string.Format("[{0}]", fields);
}

If you are looking for something that will concatenate properties into a string that looks like a JSON string (and that would be a better way to handle it), you can use something like the following:
private static string CreateOutput(CreateTrialUserHubspotViewModel trialUser)
{
var properties = trialUser.GetType().GetProperties().Where(x => Attribute.IsDefined(x, typeof(HubspotAttribute))).ToList();
var values = properties.Select(x =>
{
var att = x.GetCustomAttribute(typeof(HubspotAttribute));
var key = ((HubspotAttribute)att).hubspotValue;
var val = x.GetValue(trialUser);
return $"{key}:{val}";
});
var sb = new StringBuilder();
values.ToList().ForEach(v =>
{
sb.Append(v);
if (values.Last() != v) sb.Append(',');
});
return sb.ToString();
}

Convert list of items to list of tree nodes that have children

I have the following class
public class Item
{
public int Id { get; set; }
public int? ParentId { get; set; }
public string Text { get; set; }
}
And the following class for tree view
public class TreeViewModel
{
public TreeViewModel()
{
this.Children = new List<TreeViewModel>();
}
public int Id { get; set; }
public int NodeId { get; set; }
public string Text { get; set; }
public bool Expanded { get; set; }
public bool Checked { get; set; }
public bool HasChildren
{
get { return Children.Any(); }
}
public IList<TreeViewModel> Children { get; private set; }
}
I will receive list of items and I would to convert it to tree.
the item that not have parent id it will the main node.
example: if i have the following items
item[0] = Id:0 Text:User ParentId:3
item[1] = Id:1 Text:Role ParentId:3
item[2] = Id:2 Text:SubUser ParentId:0
item[3] = Id:3 Text:Admin ParentId:null
item[4] = Id:4 Text:SuperAdmin ParentId:null
item[5] = Id:5 Text:Doha ParentId:4
the following item it will list of tree
I tried to make recursive function to do that , but i have no result

You don't need a recursive function to do this:
var models = items.Select(i => new TreeViewModel
{
Id = i.Id,
...
}).ToList();
foreach (var model in models){
model.Children.AddRange(models.Where(m => m.ParentId == model.Id));
}
If you then want to get the roots of your tree, you can use:
var roots = models.Where(m => !m.ParentId.HasValue);

Here is a fast O(N) time complexity method of doing that:
List<Item> list = ...;
// Pre create all nodes and build map by Id for fast lookup
var nodeById = list
.Select(item => new TreeViewModel { Id = item.Id, Text = item.Text })
.ToDictionary(item => item.Id);
// Build hierarchy
var tree = new List<TreeViewModel>();
foreach (var item in list)
{
var nodeList = item.ParentId == null ? tree, nodeById[item.ParentId.Value].Children;
nodeList.Add(nodeById[item.Id]);
}

How to copy a List<> to another List<> with Comparsion in c#

I an having Two Lists. I want to get the matched and unmatched values based on ID and add the results to another List. I can get both of these using Intersect/Except.
But I can get only ID in the resultant variables (matches and unmatches) . I need all the properties in the Template.
List<Template> listForTemplate = new List<Template>();
List<Template1> listForTemplate1 = new List<Template1>();
var matches = listForTemplate .Select(f => f.ID)
.Intersect(listForTemplate1 .Select(b => b.ID));
var ummatches = listForTemplate .Select(f => f.ID)
.Except(listForTemplate1.Select(b => b.ID));
public class Template
{
public string ID{ get; set; }
public string Name{ get; set; }
public string Age{ get; set; }
public string Place{ get; set; }
public string City{ get; set; }
public string State{ get; set; }
public string Country{ get; set; }
}
public class Template1
{
public string ID{ get; set; }
}

If you don't want to implement IEquality for this simple task, you can just modify your LINQ queries:
var matches = listForTemplate.Where(f => listForTemplate1.Any(b => b.ID == f.ID));
and
var unmatches = listForTemplate.Where(f => listForTemplate1.All(b => b.ID != f.ID));
You might want to check for null before accessing ID, but it should work.

You are looking for the overloaded function, with the second parameter IEqualityComparer. So make your comparer ( example: http://www.blackwasp.co.uk/IEqualityComparer.aspx ), and use the same comparer in intersect / except.
And for the generic part: maybe you should have a common interface for templates e.g. ObjectWithID describing that the class have a string ID property. Or simply use dynamic in your comparer (but I think this is very-very antipattern because you can have run time errors if using for the bad type).
You also have a problem: intersecting two collections with two different types will result in a collection of Object (common parent class). Then you have to cast a lot (antipattern). I advise you to make a common abstract class/interface for your template classes, and it is working. If you need to cast the elements back, do not cast, but use the visitior pattern: http://en.wikipedia.org/wiki/Visitor_pattern
Example (good):
static void Main(string[] args)
{
// http://stackoverflow.com/questions/16496998/how-to-copy-a-list-to-another-list-with-comparsion-in-c-sharp
List<Template> listForTemplate = new Template[] {
new Template(){ID = "1"},
new Template(){ID = "2"},
new Template(){ID = "3"},
new Template(){ID = "4"},
new Template(){ID = "5"},
new Template(){ID = "6"},
}.ToList();
List<Template1> listForTemplate1 = new Template1[] {
new Template1(){ID = "1"},
new Template1(){ID = "3"},
new Template1(){ID = "5"}
}.ToList();
var comp = new ObjectWithIDComparer();
var matches = listForTemplate.Intersect(listForTemplate1, comp);
var ummatches = listForTemplate.Except(listForTemplate1, comp);
Console.WriteLine("Matches:");
foreach (var item in matches) // note that item is instance of ObjectWithID
{
Console.WriteLine("{0}", item.ID);
}
Console.WriteLine();
Console.WriteLine("Ummatches:");
foreach (var item in ummatches) // note that item is instance of ObjectWithID
{
Console.WriteLine("{0}", item.ID);
}
Console.WriteLine();
}
}
public class ObjectWithIDComparer : IEqualityComparer<ObjectWithID>
{
public bool Equals(ObjectWithID x, ObjectWithID y)
{
return x.ID == y.ID;
}
public int GetHashCode(ObjectWithID obj)
{
return obj.ID.GetHashCode();
}
}
public interface ObjectWithID {
string ID { get; set; }
}
public class Template : ObjectWithID
{
public string ID { get; set; }
public string Name { get; set; }
public string Age { get; set; }
public string Place { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Country { get; set; }
}
public class Template1 : ObjectWithID
{
public string ID { get; set; }
}
Output:
Matches:
1
3
5
Ummatches:
2
4
6
Press any key to continue . . .

For comparison, this should also work (the first part is a variation on #MAV's answer):
var matches = from item in listForTemplate
join id in listForTemplate1 on item.ID equals id.ID
select item;
var unmatches = listForTemplate.Where(item => matches.All(elem => elem.ID != item.ID));
matches and unmatches will both be IEnumerable<Template> which is the type you require.
However, MAV's answer works fine so I'd go for that one.

As mentioned, Implement the IEqualityComparer<T> interface.
IEqualityComparer<T> MSDN
Then use this as an argument in your method for Except() and Intersect()
Intersect
There is a good example of how to do so on the link for the Intersect() method.

If you don't absolutely have to use LINQ, why not code something like this?
var matches = new List<Template>();
var unmatches = new List<Template>();
foreach (var entry in listForTemplate)
{
bool matched = false;
foreach (var t1Entry in listForTemplate1)
{
if (entry.ID == t1Entry.ID)
{
matches.Add(entry);
matched = true;
break;
}
}
if (!matched)
{
unmatches.Add(entry);
}
}
A disadvantage of the LINQ approach is that you're traversing the lists twice.