QueryableEx.If(TResult) Method (IQueryProvider, Expression(Func(Boolean)), IEnumerable(TResult))

QueryableExIfTResult Method (IQueryProvider, ExpressionFuncBoolean, IEnumerableTResult)

Returns an enumerable sequence if the evaluation result of the given condition is true, otherwise returns an empty sequence.

Namespace: System.Linq
Assembly: System.Interactive.Providers (in System.Interactive.Providers.dll) Version: 1.2.0.0

Syntax

public static IQueryable<TResult> If<TResult>(
	this IQueryProvider provider,
	Expression<Func<bool>> condition,
	IEnumerable<TResult> thenSource
)

provider: Type: System.LinqIQueryProvider
Query provider.
condition: Type: System.Linq.ExpressionsExpressionFuncBoolean
Condition to evaluate.
thenSource: Type: System.Collections.GenericIEnumerableTResult
Sequence to return in case the condition evaluates true.

Type: IQueryableTResult
The given input sequence if the condition evaluates true; otherwise, an empty sequence.

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