How do I define a method in an anonymous type?

Question

How do I go about defining a method, e.g. void doSuff() in an anonymous type? All documentation I can find uses only anonymous restricted basically to property lists. Can I even define a method in an anonymous type?

EDIT: OK, a quick look at very quick answers tells me this is impossible. Is there any way at all to construct a type dynamically and add an anonymous method to a delegate property on that type? I'm looking for a C# way to accomplish what the following JavaScript does:

...
person.getCreditLimit = function() { ... }
...

Answer 1

You cant, at least not up to .NET 3.5.

Answer 2

You can't. But here is what you could try:

var test = new { Foo = new Func<string>(() => "hello") };
test.Foo.Invoke();

Answer 3

You can't. Anonymouse types only contain properties with public get modifiers and overrides of the GetHashCode(), Equals() and ToString().

var myclass = new { Name = "Andy", Location = "Bellingham", Sector = 0, };

From reflector:

[CompilerGenerated, DebuggerDisplay(@"\{ Name = {Name}, Location = {Location}, Sector = {Sector} }", Type="<Anonymous Type>")]
internal sealed class <>f__AnonymousType0<<Name>j__TPar, <Location>j__TPar, <Sector>j__TPar>
{
    // Fields
    [DebuggerBrowsable(DebuggerBrowsableState.Never)]
    private readonly <Location>j__TPar <Location>i__Field;
    [DebuggerBrowsable(DebuggerBrowsableState.Never)]
    private readonly <Name>j__TPar <Name>i__Field;
    [DebuggerBrowsable(DebuggerBrowsableState.Never)]
    private readonly <Sector>j__TPar <Sector>i__Field;

    // Methods
    [DebuggerHidden]
    public <>f__AnonymousType0(<Name>j__TPar Name, <Location>j__TPar Location, <Sector>j__TPar Sector)
    {
        this.<Name>i__Field = Name;
        this.<Location>i__Field = Location;
        this.<Sector>i__Field = Sector;
    }

    [DebuggerHidden]
    public override bool Equals(object value)
    {
        var type = value as <>f__AnonymousType0<<Name>j__TPar, <Location>j__TPar, <Sector>j__TPar>;
        return ((((type != null) && EqualityComparer<<Name>j__TPar>.Default.Equals(this.<Name>i__Field, type.<Name>i__Field)) && EqualityComparer<<Location>j__TPar>.Default.Equals(this.<Location>i__Field, type.<Location>i__Field)) && EqualityComparer<<Sector>j__TPar>.Default.Equals(this.<Sector>i__Field, type.<Sector>i__Field));
    }

    [DebuggerHidden]
    public override int GetHashCode()
    {
        int num = 0x5fabc4ba;
        num = (-1521134295 * num) + EqualityComparer<<Name>j__TPar>.Default.GetHashCode(this.<Name>i__Field);
        num = (-1521134295 * num) + EqualityComparer<<Location>j__TPar>.Default.GetHashCode(this.<Location>i__Field);
        return ((-1521134295 * num) + EqualityComparer<<Sector>j__TPar>.Default.GetHashCode(this.<Sector>i__Field));
    }

    [DebuggerHidden]
    public override string ToString()
    {
        StringBuilder builder = new StringBuilder();
        builder.Append("{ Name = ");
        builder.Append(this.<Name>i__Field);
        builder.Append(", Location = ");
        builder.Append(this.<Location>i__Field);
        builder.Append(", Sector = ");
        builder.Append(this.<Sector>i__Field);
        builder.Append(" }");
        return builder.ToString();
    }

    // Properties
    public <Location>j__TPar Location
    {
        get
        {
            return this.<Location>i__Field;
        }
    }

    public <Name>j__TPar Name
    {
        get
        {
            return this.<Name>i__Field;
        }
    }

    public <Sector>j__TPar Sector
    {
        get
        {
            return this.<Sector>i__Field;
        }
    }
}

Answer 4

Well, you can. With delegates you just treat methods as data:

var myMethods = from x in new[] { "test" }
                select new { DoStuff = new Func<string>(() => x) };

var method = myMethods.First();
var text = method.DoStuff();

What do you think the value of "text" is?

With the Action<> and Func<> generic types you can put (almost) whatever you want in there. Almost, because you cannot for instance access other properties on the anonymous type, like this:

var myMethods = from x in new[] { "test" }
                select new { Text = x, DoStuff = new Func<string>(() => Text) };

Answer 5

What about this:

        var anonType = new
        {
            FirstName = "James",
            LastName = "Bond",
            FullName = new Action<string, string>(
                (x, y) =>
                    { 
                        Console.WriteLine(x + y );
                    })                
        };

        anonType.FullName("Roger","Moore");

Basically using a Lambda for the delegate

Answer 6

You absolutely can, with delegates:

Action action = MethoThatDoesSomething;
var obj = new
          {
              DoSomething = action
          };

obj.DoSomething();

I tried with a lambda in the new { ... } and that didn't work, but the above is totally fine.

Answer 7

You can:

// this line should be in class body, not in method
delegate void MyDelegate(); 
var Obj = new {
    MyDel = new MyDelegate(delegate() { MessageBox.Show("yee-haw"); })
};
Obj.MyDel();

If you don't want to declare a delegate type, you can use System.Func<>:

var Obj = new {
    MyFunc = new Func<string>( delegate() { return "yee-haw"; })
};
MessageBox.Show(Obj.MyFunc());