Question

I’m completely new to reflection and I’m trying to call a class name from a db record and then load the class and run it but I’m pulling my hair out on where I’m going wrong, its probably something really silly I’m missing.

As an example I have my class in a different project and scripts folder, then call the name of it from the db record.

className = String.Format("Utilities.Scripts.{0}", script.ScriptClass);

Then in my main program I have

// Get a type from the string 
Type type = Type.GetType(className);

// Create an instance of that type
Object obj = Activator.CreateInstance(type);

// Retrieve the method you are looking for
MethodInfo methodInfo = type.GetMethod("start");

// Invoke the method on the instance we created above
methodInfo.Invoke(obj, null);

But I am getting the error as when debugging I can see my details passed into the GetType(className) but nothing goes through to the type and as such into the obj where it is erroring.

Answer 1

You need to supply the Assembly Qualified Name of the type (as mentioned here) since the class is in a different project. Also, make sure that the assembly you are trying to load the type from is either in the same folder as the assembly trying to load it, or in the GAC.

For a class defined as below:

namespace Foo.Bar
{
    public class Class1
    {

    }
}

The full class name is Foo.Bar.Class1. The assembly qualified name also specifies the full name of the assembly, as in Foo.Bar.Class1, Foo.Bar, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35. You can find the Assembly Qualified Name of your type with somthing like:

Console.WriteLine(typeof(Foo.Bar.Class1).AssemblyQualifiedName)