I wanna use the C# code file in VB.Net project Which is windows based application. But that C# class is not using in VB.NET application. How Can I perform this task.
Compile the C# class in it's own C# class library (DLL) and then in your VB project, add a reference to the C# DLL. You can then use the class in your VB project.
If, however, you want to include the source code of the C# class in your VB project then you will have to convert the class from C# to VB. There are various methods of doing this, such as the online tool Convert C# to VB.NET