How to display login form again after invalid login?

Question

how can i redirect back to the Login form in win form application after invalid login write now i am trying this in program.cs

Application.EnableVisualStyles();
Application.SetCompatibleTextRenderingDefault(false);
// Application.Run(new frmLogin());
frmLogin fm = new frmLogin();

fm.ShowDialog();
if (fm.DialogResult == DialogResult.OK && Global.Login)
    Application.Run(new MDIParent1());
else if(fm.DialogResult==DialogResult.Cancel)
{
    MessageBox.Show("Wrong Username Or Password");
    Application.Run(new frmLogin());
    //fm.ShowDialog();
}

Answer 1

Why are you not handling the "Invalid Login" in the Login form itself? Dont return to the calling form until the login is valid.

Answer 2

on frmLogin implementation check validity and show message box:

// in frmLogin.cs
if(/* loginn is valid*/)
{
    this.DialogResult = DialogResult.OK;
    this.Close();
}
else
{
    MessageBox.Show("Wrong Username Or Password");
}