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MJ Ferdous Posted: 02-27-2009 8:06 PM

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Hi,

Reflection has the ability for a program to dynamically inspect itself, is possibly one of the most powerful features of modern programming languages like C# and Java. The following is a simple example of how to interrogate the current C# assembly, locate all the classes that are derived from a base class, and then dynamically created and executed an instance of the class.

But I need to create an Instance using a variable by passing a parameter class name as string. See the following code:  

you can call this by GetObject("Company","");// company is a class inherited from BaseOB

public static object GetObject(string nameClass, string request){

Assembly asm = Assembly.GetExecutingAssembly(); // take the current assembly
   foreach (Type type in asm.GetTypes()) // for each type Class, Form
   {
    if (type.IsClass && type.Name == nomeClasse ) //find all the Types that are “Classes”  
    {
     PropertyInfo[] properties = type.GetProperties();

     foreach(PropertyInfo prop in properties)
     {
      string s = prop.Name;  //will return the name of each properties    
     }     
     ConstructorInfo ci = type.GetConstructor(new Type[] { });
     Company tmp = (Company)ci.Invoke(new Object[] { }) ;
     //BaseOB objBase  = (Company)ci.Invoke(new Object[] { }) ;
     tmp.CompanyName = "OT";
     tmp.run();
     //objBase.run();     
    } } 

return new object(); }

It works Fine. Does anyone have any idea on that how to create an instance (i.e. Company ) from the parameter value without knowing Class name.

This type of Conversion works but if i do something like this in my code then doesn work. it shows runtime exception that is not possible to convert in BaseOB  type from basic object t ype. Somthing like this.

string sType = "System.Int32";
object o1 = "123";
object o2 = Convert.ChangeType(o1, Type.GetType(sType));
Type t = o2.GetType(); // this returns Int32 Type

Let me know if you solved this kind of problem. Thanks a lot

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MJ Ferdous replied on 02-27-2009 11:15 PM

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Hi,

I got an article link from my colleague to solve my problem. To resolve this problem just use the Generics (obviously for versions of the framework from 2.0 onwards). Since i am using 1.1 i can't use generics.

I used the following code to set values in the properties without converting

Object o = Activator.CreateInstance( type );
     System.Reflection.PropertyInfo p_i;
     string CompanyCodedd = "CompanyCode";
     p_i = type.GetProperty("CompanyName");
     p_i.SetValue(o,"OT",null);
 

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Morshed Anwar replied on 03-30-2009 2:19 PM

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nice to hear that you get the solution .......but some times reflection is lil more coslty. If you wanna to convert a type to where you r going to mapped the property then I will suggest dont go for the costly operations.You can use expression tree in place of reflection .You can take a look on this blog-

http://morshedanwar.wordpress.com/2009/03/24/type-convertion-using-expression-in-place-of-reflection-cnet/