calling an Extension Method from another Extension method

Question

Hi All,

Does anybody know/has experience calling an extension method from another extension method? Is it even possible at first place?

Like, I've an ext. method (defined for extending DataContext class) :

pubic static SaveEntity<T>(this DataContext dc, T Entity)  where T : class
{
    ....
    ....
}

now, the question is : Can I call this method from another ext. method (again defined for extending DataContext class) like :

public static SaveEntityCollection<T>(this DataContext dc, List<T> Colln)  where T : class
{
    foreach(T ent in Colln)
    {
        if(ent.IsNew) dc.SaveEntity(?????)
        ....
        ....
        if(ent.IsModified) dc.SaveEntity(?????)
        ....

    }
}

???? = unknown syntax

I need this type of functionality in one of my projects & want to know if this is a supported language-feature and if so, what could be the syntax for the same.

Will appreciate any help/link in this regard,

Thanks in advance,

Regards,
Rajesh Moriyani

Answer 1

Hi,

I haven't tried it, but I think you can do it if both methods are in different classes.

Answer 2

1	using System;
2	using System.Collections.Generic;
3	using System.Linq;
4	using System.Text;
5	using System.Data.Linq;
6
7	namespace ExtensionMethods
8	{
9	public interface IEntity
10	{
11	bool IsNew { get; set; }
12	bool IsModified { get; set; }
13	}
14
15	public class Customer : IEntity
16	{
17	public bool IsNew {get; set;}
18	public bool IsModified {get; set;}
19	}
20
21	public partial class Northwind : DataContext
22	{
23	public Table<Customer> Customers;
24	public Northwind(string connection) : base(connection) { }
25	}
26
27	static class Extensions
28	{
29	public static void SaveEntity<T>(this DataContext dc, T entity)
30	{
31	Console.WriteLine(string.Format("{0}({1}) saved", entity.GetType().Name, entity.GetHashCode()));
32	}
33
34	public static void SaveEntityCollection<T>(this DataContext dc, List<T> colln)
35	{
36	foreach(T ent in colln)
37	{
38	if (((IEntity)ent).IsNew || ((IEntity)ent).IsModified)
39	{
40	dc.SaveEntity(ent);
41	}
42	}
43	}
44	}
45
46	class Program
47	{
48	static void Main(string[] args)
49	{
50	List<Customer> myList = new List<Customer>();
51
52	{
53	myList.Add(new Customer() { IsModified = false, IsNew = true });
54	myList.Add(new Customer() { IsModified = false, IsNew = true });
55	myList.Add(new Customer() { IsModified = false, IsNew = true });
56	myList.Add(new Customer() { IsModified = false, IsNew = true });
57	myList.Add(new Customer() { IsModified = false, IsNew = true });
58	};
59
60	// DataContext takes a connection string.
61	DataContext db = new DataContext(@"c:\Northwnd.mdf");
62
63	db.SaveEntityCollection(myList);
64	Console.ReadKey();
65	}
66	}
67	}
68

Hello Rajesh

 

Does the above code help you in resolving your query?

 

Please let me know,

Sunil Vishwas

 

 

Answer 3

Yes: An extension method can call an another extension method: Please find the following example:

public static class ExtensionClass1

{

public static string Info<T> (this T obj) where T:class

{

return obj.MoreInfo<T>() + ":" +  obj.GetType().Name;

}

}

public static class ExtensionClass2

{

public static string MoreInfo<T>(this object obj) where T: class

{

return obj.GetType().Assembly.FullName;

}

}

Thanks,
Tariq A Karim (http://www.moplah.blogspot.com)

Answer 4

Hi All,

Thanks one and all (specially Sunil) for reading my post & answering with code-snippets. It's really very helpful.

Thanking you very much,

Regards,
Rajesh Moriyani