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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.

#Purpose

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.

#Availability

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.

#Notes

#Example

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

Result:

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

#Screenshot

rsIntroduceFormatItemCSharp

See Also