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StringBuilder.Replace Method (String, String, Int32, Int32)

Replaces, within a substring of this instance, all occurrences of a specified string with another specified string.

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

member Replace : 
        oldValue:string * 
        newValue:string * 
        startIndex:int * 
        count:int -> StringBuilder 


Type: System.String
The string to replace.
Type: System.String
The string that replaces oldValue, or a null reference (Nothing in Visual Basic).
Type: System.Int32
The position in this instance where the substring begins.
Type: System.Int32
The length of the substring.

Return Value

Type: System.Text.StringBuilder
A reference to this instance with all instances of oldValue replaced by newValue in the range from startIndex to startIndex + count - 1.


oldValue is a null reference (Nothing in Visual Basic).


The length of oldValue is zero.


startIndex or count is less than zero.


startIndex plus count indicates a character position not within this instance.


Enlarging the value of this instance would exceed MaxCapacity.

The strings to replace are checked on an ordinal basis; that is, the replacement is not culture-aware. If newValue is a null reference (Nothing in Visual Basic), all occurrences of oldValue are removed. This method is case-sensitive.

The following example demonstrates the Replace method.

No code example is currently available or this language may not be supported.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.