CqlQueryExtensionsFirstOrDefaultTSource Method (TableTSource, ExpressionFuncTSource, Boolean)

Returns a CqlQuery which after execution will return the first element of the sequence that satisfies a condition or a default value if no such element is found. To execute this CqlQuery use Execute() method.

Namespace: Cassandra.Data.Linq
Assembly: Cassandra (in Cassandra.dll) Version: 3.11.0

Syntax

Copy

public static CqlQuerySingleElement<TSource> FirstOrDefault<TSource>(
	this Table<TSource> source,
	Expression<Func<TSource, bool>> predicate
)

Parameters

source: Type: Cassandra.Data.LinqTableTSource
The Table<TSource> to return the first element of.
predicate: Type: System.Linq.ExpressionsExpressionFuncTSource, Boolean
A function to test each element for a condition.

Type Parameters

TSource: The type of the elements of source.

Return Value

Type: CqlQuerySingleElementTSource
a CqlQuery<TSource> which after execution will return default(TSource) if source is empty or if no element passes the test specified by predicate, otherwise the first element in source that passes the test specified by predicate.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type TableTSource. 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).

Reference

CqlQueryExtensions Class

FirstOrDefault Overload

Cassandra.Data.Linq Namespace