How to Invoke and retrieve data from a method inside a dll using interface?

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.NET3.5

How to Invoke and retrieve data from a method inside a dll using interface?
INFO:
we are using windows forms and sql server2005,we pass data as xml and uses stored procedures .In the application layer client is not providing internet,mean while the business and database layer have internet connectivity.
we have placed business object class files as dll in a shared folder of client machine which has internet connectivity.how can i call a function inside the dll ,pass parameters through an interface class inside the dll and retrieve the output
on the Business layer we have an interface class "IGetData"

C#

namespace WNHRP01BO
{
   public interface IGetData
    { 
        string GetData(string Xml, string ClassName, string Mode);
    }
}

class file in the Business layer having function "GetData" ,which is to be called is shown below

C#

namespace WNHRP01BO
{
    public class hb007001C0 : WNHRP01BO.IGetData
	{
		PLABS.DbProvider _objDb = PLABS.DbProvider.MSSql;
		public hb007001C0()
		{
			
		}
		#region IGetData Members
		public string GetData(string Xml,  string AddParams,string Mode)
		{
			String retXml = string.Empty;
			if (Mode == "I")
				{
					PLABS.DAL objDbHelper = new PLABS.DAL();
					retXml= objDbHelper.insertSP("hb007001F0_IU", Xml, this._objDb);
				}
            return retXml;
     
		}
		#endregion
	}
}

"CallBOCommon" a class in application layer ,through which the business layer is connected either using webservice or referenced project as shown below

C#

namespace UtilsApp
{
    public class CallBOCommon
    {
        public String CallWS(String Xml, String ClassName, String Mode)
        {
          //////calling from referenced business object project "WNHRP01BO"
          //// Type tp = Type.GetType(ClassName);
//String retDat = (((WNHRP01BO.IGetData)Activator.CreateInstance(tp)).GetData(Xml, "", Mode));
     ////   return retDat;

       //////////calling webservice
         //Connector.AuthWS obj = new Connector.AuthWS();
         //Xml = PLABS.Utils.Compress(Xml);
 //String retDat = obj.CallWS(Xml, ClassName, Mode, "http://somehostingserver.in/service.asmx");
          //return retDat;

///actually what i am trying to impliment is to replace below lines 
//String retDat = (((WNHRP01BO.IGetData)Activator.CreateInstance(tp)).GetData(Xml, "", Mode));
//return retDat;with ur provided code 
//but i dont know how to specify the type of Activator.CreateInstance(tp) 
//as (WNHRP01BO.IGetData) while loading from dll

  //////i am getting class name as "WNHRP01BO.hb007001C0,WNHRP01BO"
 //////BOClass =WNHRP01BO.hb007001C0
 string BOClass = ClassName.Split(',')[0].ToString();
/////////reading from dll on the shared folder of client machine
 Assembly a = Assembly.LoadFile(@"D:\DLL\live hrp\WNHRP01BO.dll");
 var aTypes = a.GetTypes();
 Type t = aTypes.FirstOrDefault(tp => tp.FullName == BOClass);
// how to specify the type of Activator.CreateInstance(tp) as (WNHRP01BO.IGetData)
 object obj = Activator.CreateInstance(t);
/////cant list GetRuntimeMethods() from type
     MethodInfo MI = t.GetMethods().FirstOrDefault(m1 => m1.Name.IndexOf("GetData") > 0);
 var retVal = MI.Invoke(obj, new object[] { Xml, ClassName, Mode });
////am getting value Of MI as Null
//////what am i missing here?

        }

    }

Posted 6-Mar-14 22:55pm

george4986

Updated 10-Mar-14 0:54am

v2

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Vedat Ozan Oner · Answer 1 · 2014-03-06T23:35:00

Solution 2

I think you can do something like the following:

C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;

namespace Test_Reflection2
{
    class Program
    {
        static void Main(string[] args)
        {
            // load assembly
            Assembly l = Assembly.LoadFile(@"d:\tmp\Test_ReflectionSampleLib.dll");
            // types in that assembly
            var ts = l.GetTypes();

            // find interface
            Type i = ts.FirstOrDefault(t1 => t1.Name == "IGetData" && t1.IsInterface);
            // find class which implements interface
            Type c = ts.FirstOrDefault(t1 => t1.IsClass && t1.GetInterface("IGetData") != null);
            // create an instance of class
            object o = Activator.CreateInstance(c);
            // get method. not good way to find the method!!
            MethodInfo mi = c.GetRuntimeMethods().FirstOrDefault(m1 => m1.Name.IndexOf("IGetData.GetData") > 0);
            // invoke it
            var retval = mi.Invoke(o, new object[] { string.Empty, string.Empty, string.Empty });
            Console.WriteLine(retval);
        }
    }
}

Posted 6-Mar-14 23:35pm

Vedat Ozan Oner

Comments

george4986 7-Mar-14 19:52pm

thanks for the reply ;-)
i will try ur solution and get back to u soon .

george4986 10-Mar-14 7:51am

I have tried below code also , shows error

string BOClass = ClassName.Split(',')[0].ToString();

Assembly a = Assembly.LoadFile(@"D:\DLL\live hrp\WNHRP01BO.dll");

var aTypes = a.GetTypes();

Type t = aTypes.FirstOrDefault(tp => tp.FullName == BOClass);

Type iT = aTypes.FirstOrDefault(tp => tp.Name=="IGetData");

object obj = (iT)Activator.CreateInstance(t);

MethodInfo MI = t.GetMethods().FirstOrDefault(m1 => m1.Name.IndexOf("GetData") > 0);

var retVal = MI.Invoke(obj, new object[] { Xml, ClassName, Mode });

george4986 10-Mar-14 6:16am

whats the use of Type i in ur code?is it needed?

george4986 10-Mar-14 6:20am

actually what i am trying to impliment is to replace below lines

String retDat = (((WNHRP01BO.IGetData)Activator.CreateInstance(tp)).GetData(Xml, "", Mode));

return retDat;with ur provided code

but i dont know how to specify the type of Activator.CreateInstance(tp)

as (WNHRP01BO.IGetData) while loading from dllmy code

//////i am getting class name as "WNHRP01BO.hb007001C0,WNHRP01BO"

//////BOClass =WNHRP01BO.hb007001C0

string BOClass = ClassName.Split(',')[0].ToString();

Assembly a = Assembly.LoadFile(@"D:\DLL\live hrp\WNHRP01BO.dll");

var aTypes = a.GetTypes();

Type t = aTypes.FirstOrDefault(tp => tp.FullName == BOClass);
// how to specify the type of Activator.CreateInstance(tp) as (WNHRP01BO.IGetData)

object obj = Activator.CreateInstance(t);

/////cant list GetRuntimeMethods() from type

MethodInfo MI = t.GetMethods().FirstOrDefault(m1 => m1.Name.IndexOf("GetData") > 0);

var retVal = MI.Invoke(obj, new object[] { Xml, ClassName, Mode });

////am getting value Of MI as Null

smithjdst 10-Mar-14 15:12pm

You could try switching from MethodInfo to ConstructorInfo. Also, is the method your invoking public, are the input values in same order and same types as the method parameters?

george4986 11-Mar-14 0:44am

method i am invoking is public,input value in same order and same type as string.as u suggested using construtor info how can i search the method in dll and invoke

Ramug10 · Answer 2 · 2014-03-06T23:06:00

Solution 1

In your Application Layer right click on the project and select add reference then choose location of "WNHRP01BO.dll" and ok.
Now in CallBOCommon class import the namespace WNHRP01BO and access the class "hb007001C0".
Create object for this class and call getdata() through this object.

Thanks,
-RG

Posted 6-Mar-14 23:06pm

Ramug10

Comments

george4986 7-Mar-14 19:52pm

thanks for the reply ;-)
i will try ur solution and get back to u soon .

george4986 10-Mar-14 6:31am

that won't work what u suggested is in commented lines of my quetion

//////calling from referenced business object project "WNHRP01BO"
//// Type tp = Type.GetType(ClassName);
//// String retDat = (((WNHRP01BO.IGetData)Activator.CreateInstance(tp)).GetData(Xml, "", Mode));
//// return retDat;

but the dll location is on client side ,i need to load dll not as reference

smithjdst · Answer 3 · 2014-03-11T01:49:00

Try this, I have tested and it works.
using dynamic to try an prevent need for Assembly references & Type casting.

public object CallWS(string Xml, string ClassName, string Mode) {
    try {

    Assembly a;
    if ((a = Assembly.LoadFile(@"D:\DLL\live hrp\WNHRP01BO.dll")) != null) {
        var aTypes = a.ExportedTypes.ToArray();

        Type t;
        string BOClass = ClassName.Split(',')[0].ToString();
        if ((t = aTypes.FirstOrDefault(tp => tp.FullName == BOClass)) != null) {
            object obj = Activator.CreateInstance(t);
            object igd = (dynamic)obj.GetType().GetInterface("IGetData");
            object value;

        //option 1:------------------------------------>>
            value = ((dynamic)igd).InvokeMember(
                            "GetData", 
                            BindingFlags.InvokeMethod | 
                            BindingFlags.Instance | 
                            BindingFlags.Public,
                            null,
                            obj,
                            new object[] { Xml, ClassName, Mode }
                    );

        //option 2:------------------------------------>>
            MethodInfo mi = ((dynamic)igd).GetMethod("GetData");
            value =  mi.Invoke(obj, new object[] { Xml, ClassName, Mode });

            return value;
        }
    }

    return null;
    } 
    catch { return null; }
}