Regex.Replace Method (String, MatchEvaluator, Int32, Int32)
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Within a specified input substring, replaces a specified maximum number of strings that match a regular expression pattern with a string returned by a MatchEvaluator delegate.
Namespace: System.Text.RegularExpressions
Assembly: System (in System.dll)
Syntax
'Declaration
Public Function Replace ( _
input As String, _
evaluator As MatchEvaluator, _
count As Integer, _
startat As Integer _
) As String
public string Replace(
string input,
MatchEvaluator evaluator,
int count,
int startat
)
Parameters
- input
Type: System.String
The string to search for a match.
- evaluator
Type: System.Text.RegularExpressions.MatchEvaluator
A custom method that examines each match and returns either the original matched string or a replacement string.
- count
Type: System.Int32
The maximum number of times the replacement will occur.
- startat
Type: System.Int32
The character position in the input string where the search begins.
Return Value
Type: System.String
A new string that is identical to the input string, except that a replacement string takes the place of each matched string.
Exceptions
| Exception | Condition |
|---|---|
| ArgumentNullException | input is nulla null reference (Nothing in Visual Basic). -or- evaluator is nulla null reference (Nothing in Visual Basic). |
| ArgumentOutOfRangeException | startat is less than zero or greater than the length of input. |
Remarks
The Regex.Replace method is useful for replacing a regular expression match if any of the following conditions is true:
The replacement string cannot readily be specified by a regular expression replacement pattern.
The replacement string results from some processing done on the matched string.
The replacement string results from conditional processing.
The method is equivalent to calling the Regex.Matches method and passing the first countMatch objects in the returned MatchCollection collection to the evaluator delegate.
The regular expression is the pattern defined by the constructor for the current Regex object.
The evaluator parameter is the delegate for a custom method that you define and that examines each match. The custom method must have the following signature to match the MatchEvaluator delegate.
Public Function MatchEvaluatorMethod(ByVal match As Match) As String
public string MatchEvaluatorMethod(Match match)
Your custom method returns a string that replaces the matched input.
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
See Also