在MDI容器中打开另一个表单

Question

Please refer to the diagram below:

I'm looking for the best way from one form to open another form. Once the menu form is open, I want to close the login form. I have tried to do this, but I got lost when I try to call it as a child of the MDI container.

Answer 1

The reason your main form isn't showing is because once you close the login form, your application's message pump is shut down, which causes the entire application to exit. The Windows message loop is tied to the login form because that's the one you have set as the startup form in your project properties. Look in your "Program.cs" file, and you'll see the responsible bit of code: Application.Run(new LoginForm()). Check out the documentation for that method here on MSDN, which explains this in greater detail.

The best solution is to move the code out of your login form into the "Program.cs" file. When your program first starts, you'll create and show the login form as a modal dialog (which runs on a separate message loop and blocks execution of the rest of your code until it closes). When the login dialog closes, you'll check its DialogResult property to see if the login was successful. If it was, you can start the main form using Application.Run (thus creating the main message loop); otherwise, you can exit the application without showing any form at all. Something like this:

static void Main()
{
    LoginForm fLogin = new LoginForm();
    if (fLogin.ShowDialog() == DialogResult.OK)
    {
        Application.Run(new MainForm());
    }
    else
    {
        Application.Exit();
    }
}

Answer 2

if you develop WPF form, you can use ' http://wpfmdi.codeplex.com/ '. or in Win Form you could play with form such that you want

Answer 3

try this

    //global form
    LoginForm login = new LoginForm();
    public void menuOpen()
    {
       if(login.Visible)
          login.Close();
    }