WinForms on Tabpage selected run method in UserControl

Question

My Tabcontrol has 3 Tabpages. I am currently in Tabpage 1, when I would select Tabpage 2. I want to run a method in my UserControl assigned to that Tabpage. You could call this a "Focus" listener. How would I implement this? Or is this possible at all?

Edit:

Lets say I have a file named "UserControl1.cs" In here there is a method OnFocus() I would like to call this method when its Tabpage becomes the active tab. I am assigning the UserControl to the Tabpage like this:

        // AllOpenUserControls = List<UserControl> // With the active pages

        TabPage newPage = new TabPage();
        newPage.Text = title;
        newPage.AutoScroll = true;
        newPage.BackColor = SystemColors.Window;
        newPage.Controls.Add(userControl);
        AllOpenUserControls.Add(userControl);

        tabControl.TabPages.Add(newPage);

Answer 1

Add the EventHandler for SelectedIndexChanged here:

...
tabControl.TabPages.Add(newPage);
tabControl.SelectedIndexChanged += new EventHandler(userControl.OnFocus);

Your OnFocus-method should look like this:

public void OnFocus(object sender, System.EventArgs e)
{
    TabControl tc = (TabControl)sender;
    if (tc.SelectedTab == this.Parent)
    {
        //Parent-Tab is selected, do stuff...
    }
}