Reflection Problem !

Lost User

Dear Friends, assume the following namespace:

namespace MyNameSpace
 {
	public struct MyStruct
	{
          private int intVar;

          public int IntVar
           {
            get { return intVar; }
            set { intVar = value; }
           }
        }

        public class MyClass
        {
            private MyStruct structVar;
            //Public property.
            public MyStruct StructVar
            {
                get { return structVar; }
                set { structVar = value; }
            }
            public MyClass()
            {
            }
        }
}
}

This class is in a dll file (MyAssembly.dll).I wanna load this dll at runtime by reflection and change the IntVar property of StructVar of my class instance by SetValue method of PropertyInfo class.

namespace MyApplication
{
    public class MainClass
    {
        public void ChangeProperty()
        {
            Assembly asm = Assembly.LoadFrom("MyAssembly.dll");
            Type t = asm.GetType("MyNamespace.MyClass");
            PropertyInfo pInfo = t.GetProperty("StructVar");
            //Here is my problem.How can I change 'IntVar' member of this structure instance of MyClass ?
            
            pInfo.SetValue(???);
        }
    }
}

Note that this class is in a seperate dll. Best Regards. [ _ Always there is another way _ ]

rudy net

First create an instance of your class using Activator. Then you should be able to access your structure as usual. Example: Type t = asm.GetType("MyNamespace.MyClass"); MyNamespace.MyClass cls = Activator.CreateInstance(t); cls.StructVar.IntVar = 4;

Stefan Troschuetz

This should do the trick:

Assembly asm = Assembly.LoadFrom("MyAssembly.dll");
Type t = asm.GetType("MyNamespace.MyClass");
Object obj = Activator.CreateInstance(t);
PropertyInfo pInfo = t.GetProperty("StructVar");
PropertyInfo pInfo2 = pInfo.PropertyType.GetProperty("IntVar");
pInfo2.SetValue(1, pInfo.GetValue(obj, null), null);

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning." - Rick Cook

www.troschuetz.de -- modified at 13:33 Sunday 7th May, 2006

S Senthil Kumar

You simply have to call GetProperty again for IntVar, this time on pInfo.PropertyType. That will get you a reference to IntVar's property info, which you can then use to call SetValue. Just remember to call SetValue on pInfo again, as the struct instance you have is a boxed instance and setting it's member values will not affect the original struct.

object o = Activator.CreateInstance(typeof(MyClass));
PropertyInfo structPropertyInfo = typeof(MyClass).GetProperty("StructVar");
object s = structPropertyInfo.GetValue(o, null);
PropertyInfo intPropertyInfo = structPropertyInfo.PropertyType.GetProperty("IntVar");
intPropertyInfo.SetValue(s, 2, null);
structPropertyInfo.SetValue(o, s, null);
MyClass a = (MyClass)o;
Console.WriteLine(a.StructVar.IntVar);

Regards Senthil _____________________________ My Blog | My Articles | My Flickr | WinMacro

S Senthil Kumar

Stefan Troschütz wrote:

pInfo2.SetValue(1, pInfo.GetValue(obj, null), null);

That won't work, pInfo.GetValue(...) will return a boxed instance of the struct, so setting it's IntVar property won't affect the original struct. As I suggested in my post below, you can call pInfo.SetValue to set the new struct, but I wonder if there's a better way? Maybe an API function to get the struct by reference? Or is this what the compiler does when you call myClass.StructVar.IntVar = 2? Regards Senthil _____________________________ My Blog | My Articles | My Flickr | WinMacro

Stefan Troschuetz

Ups, I didn't thought so far and the code snippet was a quick, untested shot :-( Thanks for the correction. Currently no solution comes to my mind, that's better than yours. Would be interesting to dig a bit deeper into this, when having more time than now.

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning." - Rick Cook

www.troschuetz.de

Lost User

Deart Rudy. Thanx for your attention.But MyNamespace.MyClass is in a separate dll file and I haven't it at compile time.If I write this code I will receive the following error : The type or namespace name 'MyNamespace' could not be found (are you missing a using directive or an assembly reference?) Everything is at Runtime :confused: :sigh: [ _ Always there is another way _ ]

Lost User

Dear Senthil ! Thanx for your fast reply.The solution you provided worked properly. King Regards, Amir. :-D:rose: [ _ Always there is another way _ ]