Generics, Casting and Anonymous Delegates and the Where clause

I have a situation where the code looks like:

( ( TextBox ) ( _someParentControl.FindControl( “_childControlId” ) ) ).Text = “SomeText”;
( ( TextBox ) ( _someParentControl.FindControl( “_childControlId” ) ) ).Enabled = someBool;

repeat about 10 times with different child control type, parent controls, child Ids, and properties.
obviously, there’s a similarity and refactoring was in order.

private static void ExecuteOnControl( WebControl parent, string id, Action action) where T : WebControl
{
    T control = parent.FindControl( id ) as T;
    if (control != null && action != null)
    {
        action( control );
    }
}

The where clause is important because you can’t cast “As” within the function without having some limits on the generc T.

Which allowed me to shrink the example down to:
ExecuteOnControl(_parentControl, “_childControlId”, delegate(TextBox tb) { tb.Text = “someText”; });

This can be further simplified since the delegate can be declared once and used later.
Action tbDel = delegate(TextBox tb) { tb.Text = “someText”; };
ExecuteOnControl(_parentControl, “_childControlId1”, tbDel);
ExecuteOnControl(_parentControl, “_childControlId2”, tbDel);

One can argue here that the new code isn’t really that much more readable though, but it was good hacking

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