Question

How do I create a function for my following code so that i may not have to write the following whole code to make a form be used as MDICHILD Form.

Students stu = null;
private void studentsToolStripMenuItem1_Click(object sender, EventArgs e)
{
  if (stu == null || stu.IsDisposed)
  {
    stu = new Students();
    stu.MdiParent = this;
    stu.Show();
  }
  else
  {
    stu.Activate();
  }
}

Answer 1

Try this

private void CreateMdiChild<T>(ref T t) where T : Form, new()
{            
    if (t == null || t.IsDisposed)
    {
        t = new T();
        t.MdiParent = this;
        t.Show();
    }
    else
    {
        if (t.WindowState == FormWindowState.Minimized)
        {
            t.WindowState = FormWindowState.Normal;
        }
        else
        {
            t.Activate();
        }
    }
}

Usage:

Students students;
private void studentsToolStripMenuItem1_Click(object sender, EventArgs e)
{
    CreateMdiChild<Students>(ref students);
}