Loading Runtime DLL

Question

I'm trying to load a DLL runtime and invoke a method in one of the classes present in DLL.

Here is where I've loaded the DLL and invoking method,

Object[] mthdInps = new Object[2]; 
mthdInps[0] = mScope; 
string paramSrvrName = srvrName; 
mthdInps[1] = paramSrvrName; 
Assembly runTimeDLL = Assembly.LoadFrom("ClassLibrary.dll"); 
Type runTimeDLLType = runTimeDLL.GetType("ClassLibrary.Class1"); 
Object compObject = Activator.CreateInstance(runTimeDLLType, mthdInps); 
Type compClass = compObject.GetType(); 
MethodInfo mthdInfo = compClass.GetMethod("Method1"); 
string mthdResult = (string)mthdInfo.Invoke(compObject, null);

Here is the Class(present in DLL) and its method I'm trying to invoke,

namespace ClassLibrary
{
    public class Class1
    {
        public Class1()   {}
        public String Method1(Object[] inpObjs)
        {
        }
    }
}

The error I'm getting is this, Constructor on type 'ClassLibrary.Class1' not found.

Please help.

possible duplicate of [Loading DLLs at runtime in C#](http://stackoverflow.com/questions/18362368/loading-dlls-at-runtime-in-c-sharp) — Alexei Levenkov, Mar 10 '14 at 02:12

thepirat000 · Accepted Answer · 2014-03-10T02:00:11.243

3

Seems that you're passing the method parameters to the class constructor.

This:

Object compObject = Activator.CreateInstance(runTimeDLLType, mthdInps);

Should be just:

Object compObject = Activator.CreateInstance(runTimeDLLType);

And then, you call the method with the parameters:

string mthdResult = (string)mthdInfo.Invoke(compObject, new object[] { objs });

edited Mar 10 '14 at 02:00

answered Mar 10 '14 at 01:47

thepirat000

12,362
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ya I tried.. now, i'm getting "Parameter count mismatch." error. – wesfaith Mar 10 '14 at 01:54
@wesfaith try with this: `(string)mthdInfo.Invoke(compObject, new object[] { objs });` I've updated my answer. – thepirat000 Mar 10 '14 at 02:00

aw04 · Answer 2 · 2014-03-10T01:50:33.063

1

The second argument of Activator.CreateInstance(Type, Object[]) specifies parameters to the constructor. You need to modify your constructor to take Object[], or call it with just the Type, Activator.CreateInstance(Type), then call your method passing in the object array.

See msdn documentation.

edited Mar 10 '14 at 01:50

answered Mar 10 '14 at 01:44

aw04

10,857
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score 0 · Answer 3 · answered Mar 10 '14 at 02:03

Try this:

Object[] mthdInps = new Object[2]; 
mthdInps[0] = mScope; 
string paramSrvrName = srvrName; 
mthdInps[1] = paramSrvrName; 
Assembly runTimeDLL = Assembly.LoadFrom("ClassLibrary.dll"); 
Type runTimeDLLType = runTimeDLL.GetType("ClassLibrary.Class1"); 
//do not pass parameters if the constructor doesn't have 
Object compObject = Activator.CreateInstance(runTimeDLLType); 
Type compClass = compObject.GetType(); 
MethodInfo mthdInfo = compClass.GetMethod("Method1"); 

// one parameter of type object array
object[] parameters = new object[] { mthdInps };
string mthdResult = (string)mthdInfo.Invoke(compObject, parameters );

Loading Runtime DLL

3 Answers3