C#

foreach(TabPage tp in tabcontrol1.TabPages)
{
	foreach(Control ct in tp.Controls)
	{
		if(ct.GetType() == typeof(TextBox))
		{
			//do what you want
		}
	}
}

if ( ct is Textbox ) ...

TextBox temp ; // do this outside the loops
...
if ( ( temp = ct as TextBox ) != null ) ...

PIEBALDconsult wrote:

that the if ( o.GetType() == typeof(sometype) ) method is faster than both is and as

PIEBALDconsult wrote:

But cast/catch/ignore also works well with a homogenous collection, at times even better than as ! (Not that I recommend it... much.) It is horrible with a heterogenous collection.

PIEBALDconsult wrote:

I still haven't found a worthwhile use for as.

TextBox tb;
 
foreach( Control ctl in Controls )
{
   if ( null != ( tb = ctl as TextBox ) )
   {
      tb.SelectAll();
   }
}

if (null != Something) {}

// I didn't test this, just typed it out.  It may need to be adjusted.
foreach (Control tab in this.Controls) {
    TabControl t = tab as TabControl;
    if (t == null) { continue; }
    foreach (TabPage p in t.TabPages) {
        foreach (Control cp in p.Controls) {
            if (!(cp is MyControl)) { continue; }
            MyControl mc = cp as MyControl;
            // blah blah blah
        }
    }
}

foreach (ListViewItem lvi in listView1.Items) {
    if (lvi.IsTheOneIWant) {
        lvi.ForeColor = Color.Red;
    }
}