Performance of TypeCasting

is there any measurably performance difference between

((TypeA) obj).method1();
((TypeA) obj).method2();
((TypeA) obj).method3();

and

var A = (TypeA) obj;
A.method1();
A.method2();
A.method3();

when used alot of times?

I often see something like

if (((TextBox)sender).Text.Contains('.') || ((TextBox)sender).Text.Contains(','))

and wonder if this is a waste of performance.