Question

I mean that Visual C# can make a windows form app easily, but i want to know how C# can make WFA (because Visual C# just is a ide). how a Windows Application(not Console) can run in windows.

Answer 1

Well, you write exactly the same code as normal, but compile with:

csc /target:winexe (source files)

Of course if you’ve written everything in Visual Studio, you’ll have designer files – but you can write everything manually. Here’s a small WinForms Hello World app:

using System;
using System.Windows.Forms;

public class Hello
{
    [STAThread]
    static void Main()
    {
        Form form = new Form
        {
            Text = "Simple Windows Forms app",
            Controls = { new Label { Text = "Hello, world" } }
        };
        Application.Run(form);
    }
}

Having mentioned the target switch earlier, I should point out that you don’t have to use it – you can compile and run the code above using just

csc Hello.cs

I sometimes find that handy if I want to write a small test app which sends diagnostics to the console. It will start as a console app but still displays the form perfectly well.