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MongoQueryable.LongCountAsync<TSource> Method (IMongoQueryable<TSource>, Expression<Func<TSource, Boolean>>, CancellationToken)

Returns the number of elements in the specified sequence that satisfies a condition.

Namespace:  MongoDB.Driver.Linq
Assembly:  MongoDB.Driver (in MongoDB.Driver.dll) Version: 2.22.0+75246110ed1247226fcc7f8eb2c54ffab745693e
Syntax
public static Task<long> LongCountAsync<TSource>(
	this IMongoQueryable<TSource> source,
	Expression<Func<TSource, bool>> predicate,
	CancellationToken cancellationToken = default
)

Parameters

source
Type: MongoDB.Driver.Linq.IMongoQueryable<TSource>
An IMongoQueryable<T> that contains the elements to be counted.
predicate
Type: System.Linq.Expressions.Expression<Func<TSource, Boolean>>
A function to test each element for a condition.
cancellationToken (Optional)
Type: System.Threading.CancellationToken
The cancellation token.

Type Parameters

TSource
The type of the elements of source.

Return Value

Type: Task<Int64>
The number of elements in the sequence that satisfies the condition in the predicate function.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IMongoQueryable<TSource>. 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