C# – Cast with GetType()

ccastingreflection

Is it possible to cast an object to the type returned from GetType()? I'd like a generic method that can accept an object (for anonymous types) but then return an object cast as the anonymous type. I've been thinking of using the LCG DynamicMethod to build a method on a container class, but I can't exactly figure out what that would look like. The idea to cast with the GetType() method was to be able to get the anonymous type and cast an object to its actual type without actually knowing the type.

The overarching goal is to stick anonymous-typed objects into a container, that I could then share and pass between methods.

Best Answer

I can't think of why you'd want to cast as GetType(), because you wouldn't be able to do anything to useful with the result, without knowing the type at compile time anyway.

Perhaps what you are looking for, is being able to Convert. If that is the case, the following should work for you:

object input = GetSomeInput();
object result = Convert.ChangeType(input, someOtherObject.GetType());

We use this when reading values from the registry which are all stored as strings, and then stuffing them into properties using reflection.

Related Solutions

C# – How to cast int to enum

From an int:

YourEnum foo = (YourEnum)yourInt;

From a string:

YourEnum foo = (YourEnum) Enum.Parse(typeof(YourEnum), yourString);

// The foo.ToString().Contains(",") check is necessary for enumerations marked with an [Flags] attribute
if (!Enum.IsDefined(typeof(YourEnum), foo) && !foo.ToString().Contains(","))
{
    throw new InvalidOperationException($"{yourString} is not an underlying value of the YourEnum enumeration.")
}

Update:

From number you can also

YourEnum foo = (YourEnum)Enum.ToObject(typeof(YourEnum) , yourInt);

C# – Can’t operator == be applied to generic types in C#

As others have said, it will only work when T is constrained to be a reference type. Without any constraints, you can compare with null, but only null - and that comparison will always be false for non-nullable value types.

Instead of calling Equals, it's better to use an IComparer<T> - and if you have no more information, EqualityComparer<T>.Default is a good choice:

public bool Compare<T>(T x, T y)
{
    return EqualityComparer<T>.Default.Equals(x, y);
}

Aside from anything else, this avoids boxing/casting.

Best Answer

Related Solutions

C# – How to cast int to enum

C# – Can’t operator == be applied to generic types in C#

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