How to set focus to a control in a Windows Forms application?

Question

In a Windows Forms application, when do I write the code to set the focus to a control both while the application is launched and subsequently after I call

Answer 1

When the parent window is activated (that is, when it receives the "Activated" event), set the focus to the child control where you want the focus located.

private void Form_AddAppID_Activated(object sender, EventArgs e)
{
    textID.Focus();
}

Note that the tab order has nothing to do with where the focus starts. Instead, the tab order is used to decide how the focus gets transferred when the user hits the tab key.