GroupCollection Class
Returns the set of captured groups in a single match.
Assembly: System (in System.dll)
The GroupCollection type exposes the following members.
| Name | Description | |
|---|---|---|
![]() ![]() ![]() | Count | Returns the number of groups in the collection. |
![]() ![]() | IsReadOnly | Gets a value that indicates whether the collection is read-only. |
![]() ![]() | IsSynchronized | Gets a value that indicates whether access to the GroupCollection is synchronized (thread-safe). |
![]() ![]() ![]() | Item[Int32] | Enables access to a member of the collection by integer index. |
![]() ![]() ![]() | Item[String] | Enables access to a member of the collection by string index. |
![]() ![]() | SyncRoot | Gets an object that can be used to synchronize access to the GroupCollection. |
| Name | Description | |
|---|---|---|
![]() ![]() | CopyTo | Copies all the elements of the collection to the given array beginning at the given index. |
![]() ![]() ![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() ![]() ![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() ![]() ![]() | GetEnumerator | Provides an enumerator that iterates through the collection. |
![]() ![]() ![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() ![]() ![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() ![]() ![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() ![]() ![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Name | Description | |
|---|---|---|
![]() | AsParallel | Enables parallelization of a query. (Defined by ParallelEnumerable.) |
![]() ![]() | AsQueryable | Converts an IEnumerable to an IQueryable. (Defined by Queryable.) |
![]() ![]() ![]() | Cast<TResult> | Casts the elements of an IEnumerable to the specified type. (Defined by Enumerable.) |
![]() ![]() ![]() | OfType<TResult> | Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.) |
| Name | Description | |
|---|---|---|
![]() ![]() ![]() | ICollection::CopyTo | Copies all the elements of the collection to the specified array beginning at the specified index. |
![]() ![]() ![]() | ICollection::IsSynchronized | Gets a value that indicates whether access to the collection is synchronized (thread-safe). |
![]() ![]() ![]() | ICollection::SyncRoot | Gets an object that can be used to synchronize access to the collection. |
The collection is immutable (read-only) and has no public constructor. A GroupCollection object is returned by the Match::Groups property.
The collection contains one or more System.Text.RegularExpressions::Group objects. If the match is successful, the first element in the collection contains the Group object that corresponds to the entire match. Each subsequent element represents a captured group, if the regular expression includes capturing groups. If the match is unsuccessful, the collection contains a single System.Text.RegularExpressions::Group object whose Success property is false and whose Value property equals String::Empty.
To iterate through the members of the collection, you should use the collection iteration construct provided by your language (such as foreach in C# and For Each…Next in Visual Basic) instead of retrieving the enumerator that is returned by the GetEnumerator method.
The following example uses a regular expression with capturing groups to extract information about trademarks and registered trademarks used in text. The regular expression pattern is \b(\w+?)([\u00AE\u2122]), which is interpreted as shown in the following table.
Pattern | Description |
|---|---|
\b | Look for a word boundary. |
(\w+?) | Look for one or more word characters. Together, these form the trademarked name. (Note that this regular expression assumes that a trademark consists of a single word.) This is the first capturing group. |
([\u00AE\u2122]) | Look for either the ® or the ™ character. This is the second capturing group. |
For each match, the GroupCollection contains three Group objects. The first object contains the string that matches the entire regular expression. The second object, which represents the first captured group, contains the product name. The third object, which represents the second captured group, contains the trademark or registered trademark symbol.
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.








