Introduce Format Item

Introduces a new format item to the string (e.g., “{0}”, “{1}”, etc.) which represents the selected text, and if necessary, creates a new String.Format call to surround the string. The selected text is moved out to become an argument to String.Format.


This refactoring allows you to make your code more flexible, especially when followed by Introduce Local or a similar refactoring. This allows you to replace a portion of a string with a value that can change dynamically.


Available from the context menu or via shortcuts:

  • when the caret is on a String.Format method call and a fragment of the first parameter is selected.
  • when a part of a string constant is selected. In this case, a new String.Format method call is automatically generated.



string str = "Hello World";
Dim str As String = "Hello World"


string str = String.Format("Hello {0}", "World");
Dim str As String = String.Format("Hello {0}", "World")



See Also