C#: Casting with parentheses versus casting with as

I always seems to forgot the differences between casting with parentheses

Control c = FindControl( "TextBoxControl" );
TextBox tb = ( TextBox ) c; // Throws an exception if fails.

versus casting with as

Control c = FindControl( "TextBoxControl" );
TextBox tb = c as TextBox; // Return null if fails.


Here’s the differences:

• Casting with as can only be done on reference type.
• On event of a conversion failure, casting with parentheses will raises an exception, while casting with as will yields a null.
• expression as type
  is equivalent to:
  expression is type ? (type)expression : (type)null
  except that expression is evaluated only once.

Reference:

• as (C# Reference)

Tags: (, ), as, C#, cast, casting, parentheses, parenthesis