String.Replace Method (String, String)


Returns a new string in which all occurrences of a specified string in the current instance are replaced with another specified string.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

Public Function Replace (
	oldValue As String,
	newValue As String
) As String


Type: System.String

The string to be replaced.

Type: System.String

The string to replace all occurrences of oldValue.

Return Value

Type: System.String

A string that is equivalent to the current string except that all instances of oldValue are replaced with newValue. If oldValue is not found in the current instance, the method returns the current instance unchanged.

Exception Condition

oldValue is null.


oldValue is the empty string ("").

If newValue is null, all occurrences of oldValue are removed.


This method does not modify the value of the current instance. Instead, it returns a new string in which all occurrences of oldValue are replaced by newValue.

This method performs an ordinal (case-sensitive and culture-insensitive) search to find oldValue.

Because this method returns the modified string, you can chain together successive calls to the Replace method to perform multiple replacements on the original string. Method calls are executed from left to right. The following example provides an illustration.

Module Example
   Public Sub Main()
      Dim s As String = "aaa"
      Console.WriteLine("The initial string: '{0}'", s)
      s = s.Replace("a", "b").Replace("b", "c").Replace("c", "d")
      Console.WriteLine("The final string: '{0}'", s)
   End Sub
End Module
' The example displays the following output:
'       The initial string: 'aaa'
'       The final string: 'ddd'

The following example demonstrates how you can use the Replace method to correct a spelling error.

Imports System

Public Class ReplaceTest

    Public Shared Sub Main()
        Dim errString As String = "This docment uses 3 other docments to docment the docmentation"

        Console.WriteLine("The original string is:{0}'{1}'{0}", Environment.NewLine, errString)

        ' Correct the spelling of "document".  
        Dim correctString As String = errString.Replace("docment", "document")

        Console.WriteLine("After correcting the string, the result is:{0}'{1}'", Environment.NewLine, correctString)
    End Sub
End Class
' This code example produces the following output:
' The original string is:
' 'This docment uses 3 other docments to docment the docmentation'
' After correcting the string, the result is:
' 'This document uses 3 other documents to document the documentation'

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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