Switch case on type c#

Update C# 7

Yes: Source

switch(shape)
{
    case Circle c:
        WriteLine($"circle with radius {c.Radius}");
        break;
    case Rectangle s when (s.Length == s.Height):
        WriteLine($"{s.Length} x {s.Height} square");
        break;
    case Rectangle r:
        WriteLine($"{r.Length} x {r.Height} rectangle");
        break;
    default:
        WriteLine("<unknown shape>");
        break;
    case null:
        throw new ArgumentNullException(nameof(shape));
}

Prior to C# 7

No.

http://blogs.msdn.com/b/peterhal/archive/2005/07/05/435760.aspx

We get a lot of requests for addditions to the C# language and today I'm going to talk about one of the more common ones - switch on type. Switch on type looks like a pretty useful and straightforward feature: Add a switch-like construct which switches on the type of the expression, rather than the value. This might look something like this:

switch typeof(e) { 
        case int:    ... break; 
        case string: ... break; 
        case double: ... break; 
        default:     ... break; 
}

This kind of statement would be extremely useful for adding virtual method like dispatch over a disjoint type hierarchy, or over a type hierarchy containing types that you don't own. Seeing an example like this, you could easily conclude that the feature would be straightforward and useful. It might even get you thinking "Why don't those #*&%$ lazy C# language designers just make my life easier and add this simple, timesaving language feature?"

Unfortunately, like many 'simple' language features, type switch is not as simple as it first appears. The troubles start when you look at a more significant, and no less important, example like this:

class C {}
interface I {}
class D : C, I {}

switch typeof(e) {
case C: … break;
case I: … break;
default: … break;
}

Link: https://blogs.msdn.microsoft.com/peterhal/2005/07/05/many-questions-switch-on-type/

The following code works more or less as one would expect a type-switch that only looks at the actual type (e.g. what is returned by GetType()).

public static void TestTypeSwitch()
{
    var ts = new TypeSwitch()
        .Case((int x) => Console.WriteLine("int"))
        .Case((bool x) => Console.WriteLine("bool"))
        .Case((string x) => Console.WriteLine("string"));

    ts.Switch(42);     
    ts.Switch(false);  
    ts.Switch("hello"); 
}

Here is the machinery required to make it work.

public class TypeSwitch
{
    Dictionary<Type, Action<object>> matches = new Dictionary<Type, Action<object>>();
    public TypeSwitch Case<T>(Action<T> action) { matches.Add(typeof(T), (x) => action((T)x)); return this; } 
    public void Switch(object x) { matches[x.GetType()](x); }
}

Yes, you can switch on the name...

switch (obj.GetType().Name)
{
    case "TextBox":...
}