ObjectQuery<T>::GroupBy Method (String^, String^, array<ObjectParameter^>^)

 

Groups the query results by the specified criteria.

Namespace:   System.Data.Objects
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public:
ObjectQuery<DbDataRecord^>^ GroupBy(
	String^ keys,
	String^ projection,
	... array<ObjectParameter^>^ parameters
)

Parameters

keys
Type: System::String^

The key columns by which to group the results.

projection
Type: System::String^

The list of selected properties that defines the projection.

parameters
Type: array<System.Data.Objects::ObjectParameter^>^

Zero or more parameters that are used in this method.

Return Value

Type: System.Data.Objects::ObjectQuery<DbDataRecord^>^

A new ObjectQuery<T> instance of type DbDataRecord that is equivalent to the original instance with GROUP BY applied.

Exception Condition
ArgumentNullException

The query parameter is null or an empty string.

-or-

The projection parameter is null or an empty string.

GroupBy applies the projection specified by the projection parameter. This means that the ObjectQuery<T> returned by the GroupBy method is always of type DbDataRecord. For more information, see Object Queries.

This example is based on the AdventureWorks Sales Model.

This example creates a new ObjectQuery<T> object that contains the results of the existing query grouped by product name.

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

This example returns a set of nested data records that contain the Contact.LastName column, grouped and sorted alphabetically by the first letter of Contact.LastName.

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

.NET Framework
Available since 3.5
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