.NET : How do you get the Type of a null object?

Question

I have a method with an out parameter that tries to do a type conversion. Basically:

public void GetParameterValue(out object destination)
{
    object param         


        

Answer 1

@Rally25s:

string val;
GetParameterValue("parameterName", out val);

It's unclear from your message (in the answers) what the problem with that one was. If declared as:

void GetParameterValue(string parameterName, out T val)  { }

Than the call, as you wrote it above, will work (you don't need to specify the type). I'm guess that didn't work for you because you can't use a property as an "out" parameter. The way around that is to use both methods:

T GetParameterValue(string parameterName, T ununsed)  { }

This would be called like this:

MyObj.SomeProp = GetParameterValue("parameterName", MyObj.SomeProp);

which is rather kludgey, but not the worse method presented.

---

A different method, which I've used in C++, but haven't tried yet in C#, is to have GetParameterValue() some object of you own design, and then implement a number of implicit cast operators for it.

class ParameterHelper
{
   private object value;
   public ParameterHelper(object value)   { this.value = value;  }

   public static implicit operator int(ParameterHelper v)
     { return (int) v.value; }

}
ParameterHelper GetParameterValue( string parameterName);

MyObj.SomeProp = GetParameterValue("parameterName");