I use a serializer "NetStack.BitBuffer". With reflection I get all read methods like Int32 ReadInt, UInt32 ReadUInt etc.

To speed up the invoke from the methodinfo I create delegates but suddently after next time I wanted to work and even was recording it to make vlog but same code shows exception. I debugged it and all values are correct but still it is not working.

public class BitBuffer // Recreated to test it
{
    public int ReadInt()
    {
        return 1;
    }
}

[Test]
public void DelegateCreateTest()
{
    BitBuffer bitBuffer = new BitBuffer();

    MethodInfo readIntMethod = bitBuffer.GetType().GetMethod("ReadInt");

    Assert.IsNotNull(readIntMethod, "Should not be null");

    var func = (Func<object>)Delegate.CreateDelegate(typeof(Func<object>), bitBuffer, readIntMethod);

    Assert.IsNotNull(func, "Should not be null");
}

The test code above worked before the exception started to show.

System.ArgumentException: 'Cannot bind to the target method because its signature is not compatible with that of the delegate type.'

If change my self to Func<int> then it works but you could guess it.. all other methods with other return type will not work.

If I google it actually shouldn't even possible to do this except post: The identical code which I found was here and seems like it should actually work: https://stackoverflow.com/a/44595323/5103256

I really get crazy like error in the matrix and cannot explain why suddently it is not working. Tooooo bad I didn't use git to follow what is different.

CodePudding user response：

The documentation says:

the return type of a delegate is compatible with the return type of a method if the return type of the method is more restrictive than the return type of the delegate.

While all reference types are considered compatible to object, value types like int would require boxing to produce a compatible type. CreateDelegate does not offer this service.