How Do I: Call a Class with a variable name?

Question

Hello:

I posted this before but never got a solution, so I am asking again. Maybe someone else can complete this issue.

I want to be able to call a class with a variable name. The name of the class will be in a TextBox.

This is the code that I have at the moment:

string TheClass = textBoxClass_ID.Text;

object myDynamicClass = new Assembly.CreateInstance(TheClass);

myDynamicClass();

Can someone tell me what I am doing wrong?

Hirendra Sisodiya · Answer

Hello Gustavo No need to do big thing... try these lines: string TheClass = textBoxClass_ID.Text; Assembly Asm; Asm = Assembly .GetExecutingAssembly(); object myDynamicClass = Asm.CreateInstance( "ICEPack." + TheClass); Note: don't use '.cs' with classname thanks Please mark as answere if it helps

Gustavo · Answer

Hirendra: Thank You... It worked.

Jaish Mathews · Answer

Hi, I could not download your deatils from office. Will check once out of office. For calling from any other external classes use the below lines. Because GetExecutingAssembly(); will do only if your are using that assembly at run time. You may need flexibility of calling from any class in a later time. Here used class named "ClassDB". Just check that "myAssembly" is loading without a null. That's the 1st and mandatory thing. textBoxClass_ID.Text = > ". ClassDB" ; Assembly myAssembly = Assembly.LoadFrom( > ); object obj = myAssembly.CreateInstance( textBoxClass_ID.Text );

Gustavo · Answer

Jaish: I am enclosing the word document with the screen shot answers... I hope.

Jaish Mathews · Answer

NP. I attached a word document with details needed. Please send. ProjectName and AssemblyName may noot be same. So pleasae look on attached DOC and give those details. Leaving to dinner and execting your reply once returned :)

Gustavo · Answer

Jaish: I am a newbie to c#, so sorry for my ignorance. The project name is "ICEPack". The Class detail is: Name: "ClassDB.cs" or "ClassCompnay.cs" or "ClassReport.cs" and a lot more. Let assume you only need two string variables to be sent: string AAA and string BBB. Hope this answers your question. When I hard code the acces of the class Its: ClassDB ClassDB = new ClassDB(); ClassDB.Inq(AAA, BBB);

Jaish Mathews · Answer

Hi, We will not use .CS file any where. We will use full assemblyname and full class name. AssemblyName - Go to your project where your class residing. Take it's properties. From ApplicationTab you can see the Assembly name. Assembly is like .EXE of C/C++ languages, even though internally differes. So you need to use the project assembly name with full path and it's not .CS name like ClassValidateTable.cs. Assembly may contain many classes and .CS files. If you still problem, send me your project name and class details.

Gustavo · Answer

Jaish: I did a cut/paste of your code to see if it would compile and it did. Now I am changing it for my use. Your line: Assembly myAssembly = Assembly .LoadFrom( @"C:\Users\Administrator\Documents\Visual Studio 2008\Projects\WindowsFormsApplication1\WindowsFormsApplication1\bin\Debug\WindowsFormsApplication1.exe" ); Changed to: textBoxClass_ID.Text = "ClassValidateTable.cs" ; Assembly myAssembly = Assembly .LoadFrom(textBoxClass_ID.Text); It says it can not find it. The class is in my project. Do I havwe to give it the full path?

Jaish Mathews · Answer

Hi, You need to use reflection to load classes and to call it's methods dynamically. Below is a sample class which is residing in an assembly named WindowsFormsApplication1.exe. I put all the steps to call this class and it's method dynamically. Hope this will help. More over I think your class assembly is local rather than a shared assembly. namespace WindowsFormsApplication1 { public class MyClass { public string MyMethod( string name) { return "My name is " + name; } } } //Loading the assembly with full path in which my desired class exists Assembly myAssembly = Assembly .LoadFrom( @"C:\Users\Administrator\Documents\Visual Studio 2008\Projects\WindowsFormsApplication1\WindowsFormsApplication1\bin\Debug\WindowsFormsApplication1.exe" ); //Creating an instance of me desired class by referring fullname i.e. including NameSpace object obj = myAssembly.CreateInstance( "WindowsFormsApplication1.MyClass" ); //Defining the parameter types for method I need to load Type [] signature = new Type [] { typeof ( string ) }; //Loading method by mentioning the parameter types defined MethodInfo method = obj.GetType().GetMethod( "MyMethod" , signature); //Defining the parameter value for the method before calling it object [] parameters = new object [] { "Jaish Mathews" }; //Calling the method with parameter value. Return tye always object to support all types. So I just casted the type to string string nameDesc = ( string )method.Invoke(obj, parameters);