title: How to avoid Multiple Child forms shown in MDIParent C# Win Forms
body: <p>I want to avoid my child form from appearing many times when a user tries to open the child form which is already open in MDIParent.  One way to avoid this is by disabling the Controller (in my case BUTTON) but I have given a shortcut key (<kbd>Ctrl</kbd>+<kbd>L</kbd>) for this function as well. So if the user types <kbd>Ctrl</kbd>+<kbd>L</kbd>, the same child Form opens and I can see two child forms are in MDI. </p>
  
  <pre><code>private void leadsToolStripMenuItem_Click(object sender, EventArgs e)
      {
          frmWebLeads formWeblead = new frmWebLeads();
          formWeblead.MdiParent = this;
          formWeblead.WindowState = System.Windows.Forms.FormWindowState.Maximized;
          formWeblead.Show();
  
      }
  </code></pre>
  
  <p>I want to avoid this.  How can I do this? 
  <img src="https://i.stack.imgur.com/4y016.jpg" alt="enter image description here"></p>
  
  <p>In the image you can see that a child form Name  <strong>Online Leads</strong>  is opened twice as the user opened first time using Menu (LEADS) and second time by Shortcut key.  I don't want this to happen. If the form is already opened it should avoid opening another same form ... How to do this?</p>