MatchEvaluator 委托

定义

表示此方法,此方法于每次在 Replace 方法操作期间找到单一正则表达式匹配时调用。Represents the method that is called each time a regular expression match is found during a Replace method operation.

public delegate System::String ^ MatchEvaluator(Match ^ match);
public delegate string MatchEvaluator(Match match);
[System.Serializable]
public delegate string MatchEvaluator(Match match);
type MatchEvaluator = delegate of Match -> string
[<System.Serializable>]
type MatchEvaluator = delegate of Match -> string
Public Delegate Function MatchEvaluator(match As Match) As String 

参数

match
Match

Match 对象表示 Replace 方法操作期间的单个正则表达式匹配。The Match object that represents a single regular expression match during a Replace method operation.

返回值

String

MatchEvaluator 委托表示的方法返回的字符串。A string returned by the method that is represented by the MatchEvaluator delegate.

属性

示例

下面的代码示例使用 MatchEvaluator 委托将每个匹配的字符组替换为匹配项的匹配项的数目。The following code example uses the MatchEvaluator delegate to replace every matched group of characters with the number of the match occurrence.

#using <System.dll>

using namespace System;
using namespace System::Text::RegularExpressions;
ref class MyClass
{
public:
   static int i = 0;
   static String^ ReplaceCC( Match^ m )
   {
      
      // Replace each Regex cc match with the number of the occurrence.
      i++;
      return i.ToString();
   }

};

int main()
{
   String^ sInput;
   String^ sRegex;
   
   // The string to search.
   sInput = "aabbccddeeffcccgghhcccciijjcccckkcc";
   
   // A very simple regular expression.
   sRegex = "cc";
   Regex^ r = gcnew Regex( sRegex );
   
   // Assign the replace method to the MatchEvaluator delegate.
   MatchEvaluator^ myEvaluator = gcnew MatchEvaluator( &MyClass::ReplaceCC );
   
   // Write out the original string.
   Console::WriteLine( sInput );
   
   // Replace matched characters using the delegate method.
   sInput = r->Replace( sInput, myEvaluator );
   
   // Write out the modified string.
   Console::WriteLine( sInput );
}
// The example displays the following output:
//       aabbccddeeffcccgghhcccciijjcccckkcc
//       aabb11ddeeff22cgghh3344iijj5566kk77
using System;
using System.Text.RegularExpressions;

class MyClass
{
   static void Main(string[] args)
   {
      string sInput, sRegex;

      // The string to search.
      sInput = "aabbccddeeffcccgghhcccciijjcccckkcc";

      // A very simple regular expression.
      sRegex = "cc";

      Regex r = new Regex(sRegex);
        
      MyClass c = new MyClass();

      // Assign the replace method to the MatchEvaluator delegate.
      MatchEvaluator myEvaluator = new MatchEvaluator(c.ReplaceCC);
        
      // Write out the original string.
      Console.WriteLine(sInput);

      // Replace matched characters using the delegate method.
      sInput = r.Replace(sInput, myEvaluator);
      
      // Write out the modified string.
      Console.WriteLine(sInput);
   }

   public string ReplaceCC(Match m)
   // Replace each Regex cc match with the number of the occurrence.
   {
      i++;
      return i.ToString() + i.ToString();		
   }
   public static int i=0;
}
// The example displays the following output:
//       aabbccddeeffcccgghhcccciijjcccckkcc
//       aabb11ddeeff22cgghh3344iijj5566kk77
Imports System.Text.RegularExpressions

Module Module1
   Public Sub Main()
      Dim sInput, sRegex As String

      ' The string to search.
      sInput = "aabbccddeeffcccgghhcccciijjcccckkcc"

      ' A very simple regular expression.
      sRegex = "cc"

      Dim r As Regex = New Regex(sRegex)

      ' Assign the replace method to the MatchEvaluator delegate.
      Dim myEvaluator As MatchEvaluator = New MatchEvaluator(AddressOf ReplaceCC)

      ' Write out the original string.
      Console.WriteLine(sInput)
      ' Replace matched characters using the delegate method.
      sInput = r.Replace(sInput, myEvaluator)
      ' Write out the modified string.
      Console.WriteLine(sInput)
   End Sub

   Public Function ReplaceCC(ByVal m As Match) As String
      ' Replace each Regex match with the number of the match occurrence.
      static i as integer
   
      i = i + 1
      Return i.ToString() & i.ToString()
   End Function
End Module
' The example displays the following output:
'       aabbccddeeffcccgghhcccciijjcccckkcc
'       aabb11ddeeff22cgghh3344iijj5566kk77

注解

可以使用 MatchEvaluator 委托方法为替换方法(如)找到的每个匹配项执行自定义验证或操作操作 Regex.Replace(String, MatchEvaluator)You can use a MatchEvaluator delegate method to perform a custom verification or manipulation operation for each match found by a replacement method such as Regex.Replace(String, MatchEvaluator). 对于每个匹配的字符串, Replace 方法 MatchEvaluator 使用表示匹配的对象调用委托方法 MatchFor each matched string, the Replace method calls the MatchEvaluator delegate method with a Match object that represents the match. 委托方法执行你喜欢的任何处理,并返回一个字符串,该方法将该 Replace 方法替换为匹配的字符串。The delegate method performs whatever processing you prefer and returns a string that the Replace method substitutes for the matched string.

扩展方法

GetMethodInfo(Delegate)

获取指示指定委托表示的方法的对象。Gets an object that represents the method represented by the specified delegate.

适用于

另请参阅