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MatchCollection Class

Represents the set of successful matches found by iteratively applying a regular expression pattern to the input string.

System.Object
  System.Text.RegularExpressions.MatchCollection

Namespace:  System.Text.RegularExpressions
Assembly:  System (in System.dll)
[DefaultMemberAttribute("Item")]
public class MatchCollection : ICollection, 
	IEnumerable

The MatchCollection type exposes the following members.

  NameDescription
Public propertySupported by Silverlight for Windows PhoneSupported by Xbox 360CountGets the number of matches.
Public propertySupported by Silverlight for Windows PhoneSupported by Xbox 360IsReadOnlyGets a value that indicates whether the collection is read only.
Public propertySupported by Silverlight for Windows PhoneSupported by Xbox 360IsSynchronizedGets a value indicating whether access to the collection is synchronized (thread-safe).
Public propertySupported by Silverlight for Windows PhoneSupported by Xbox 360ItemGets an individual member of the collection.
Public propertySupported by Silverlight for Windows PhoneSupported by Xbox 360SyncRootGets an object that can be used to synchronize access to the collection.
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  NameDescription
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360CopyToCopies all the elements of the collection to the given array starting at the given index.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360Equals(Object)Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows PhoneSupported by Xbox 360FinalizeAllows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360GetEnumeratorProvides an enumerator in the same order as Item.
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360GetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360GetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodSupported by Silverlight for Windows PhoneSupported by Xbox 360MemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by Silverlight for Windows PhoneSupported by Xbox 360ToStringReturns a string that represents the current object. (Inherited from Object.)
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  NameDescription
Public Extension MethodSupported by Silverlight for Windows PhoneAsQueryableConverts an IEnumerable to an IQueryable. (Defined by Queryable.)
Public Extension MethodSupported by Silverlight for Windows PhoneSupported by Xbox 360Cast<TResult>Converts the elements of an IEnumerable to the specified type. (Defined by Enumerable.)
Public Extension MethodSupported by Silverlight for Windows PhoneSupported by Xbox 360OfType<TResult>Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.)
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The collection is immutable (read-only) and has no public constructor. The Regex.Matches method returns a MatchCollection object.

When applying a regular expression pattern to a particular input string, the regular expression engine uses either of two techniques to build the MatchCollection object:

  • Direct evaluation.

    The MatchCollection object is populated all at once with all matches resulting from a particular call to the Regex.Matches method. This technique is used when the collection's Count property is accessed. It typically is the more expensive method of populating the collection and entails a greater performance hit.

  • Lazy evaluation.

    The MatchCollection object is populated as needed on a match-by-match basis. It is equivalent to the regular expression engine calling the Regex.Match method repeatedly and adding each match to the collection. This technique is used when the collection is accessed through its GetEnumerator method, or when it is accessed using the foreach statement (in C#) or the For Each...Next statement (in Visual Basic).

The following example code illustrates the use of the MatchCollection class to interrogate a set of Match instances.


using System;
using System.Text.RegularExpressions;

public class Example
{

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {

      // Define a regular expression for repeated words.
      Regex rx = new Regex(@"\b(?<word>\w+)\s+(\k<word>)\b",
                           RegexOptions.IgnoreCase);

      // Define a test string.        
      string text = "The the quick brown fox  fox jumped over the lazy dog dog.";

      // Find matches.
      MatchCollection matches = rx.Matches(text);

      // Report the number of matches found.
      outputBlock.Text += String.Format("{0} matches found in:\n   {1}",
                        matches.Count,
                        text) + "\n";

      // Report on each match.
      foreach (Match match in matches)
      {
         GroupCollection groups = match.Groups;
         outputBlock.Text += String.Format("'{0}' repeated at positions {1} and {2}",
                           groups["word"].Value,
                           groups[0].Index,
                           groups[1].Index) + "\n";
      }

   }

}
// The example produces the following output:
//       3 matches found in:
//          The the quick brown fox  fox jumped over the lazy dog dog.
//       'The' repeated at positions 0 and 4
//       'fox' repeated at positions 20 and 25
//       'dog' repeated at positions 50 and 54


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

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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