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MongoQueryableGroupByTSource, TKey, TResult Method (IMongoQueryableTSource, ExpressionFuncTSource, TKey, ExpressionFuncTKey, IEnumerableTSource, TResult)

Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.

Namespace:  MongoDB.Driver.Linq
Assembly:  MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.19.1+3a2a09dd959482f665ffbb5df2557ec541597af4
Syntax
public static IMongoQueryable<TResult> GroupBy<TSource, TKey, TResult>(
	this IMongoQueryable<TSource> source,
	Expression<Func<TSource, TKey>> keySelector,
	Expression<Func<TKey, IEnumerable<TSource>, TResult>> resultSelector
)

Parameters

source
Type: MongoDB.Driver.LinqIMongoQueryableTSource
An IMongoQueryableT whose elements to group.
keySelector
Type: System.Linq.ExpressionsExpressionFuncTSource, TKey
A function to extract the key for each element.
resultSelector
Type: System.Linq.ExpressionsExpressionFuncTKey, IEnumerableTSource, TResult
A function to create a result value from each group.

Type Parameters

TSource
The type of the elements of source.
TKey
The type of the key returned by the function represented in keySelector.
TResult
The type of the result value returned by resultSelector.

Return Value

Type: IMongoQueryableTResult
An IMongoQueryableT that has a type argument of TResult and where each element represents a projection over a group and its key.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IMongoQueryableTSource. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).
See Also