Check if a specific tab page is selected (active)

Assuming you are looking out in Winform, there is a SelectedIndexChanged event for the tab

Now in it you could check for your specific tab and proceed with the logic

private void tab1_SelectedIndexChanged(object sender, EventArgs e)
{
     if (tab1.SelectedTab == tab1.TabPages["tabname"])//your specific tabname
     {
         // your stuff
     }
}