Coalesce Method (Expression, Expression)
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Expression.Coalesce Method (Expression, Expression)

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Creates a BinaryExpression that represents a coalescing operation.

Namespace:  System.Linq.Expressions
Assembly:  System.Core (in System.Core.dll)

'Declaration
Public Shared Function Coalesce ( _
	left As Expression, _
	right As Expression _
) As BinaryExpression

Parameters

left
Type: System.Linq.Expressions.Expression
An Expression to set the Left property equal to.
right
Type: System.Linq.Expressions.Expression
An Expression to set the Right property equal to.

Return Value

Type: System.Linq.Expressions.BinaryExpression
A BinaryExpression that has the NodeType property equal to Coalesce and the Left and Right properties set to the specified values.

ExceptionCondition
ArgumentNullException

left or right is Nothing.

InvalidOperationException

The Type property of left does not represent a reference type or a nullable value type.

ArgumentException

left.Type and right.Type are not convertible to each other.

The Method property of the resulting BinaryExpression is Nothing and both IsLifted and IsLiftedToNull are set to false. The Type property is equal to the result type of the coalescing operation. The Conversion property is Nothing.

Result Type

The following rules determine the result type:

  • If left.Type represents a nullable type and right.Type is implicitly convertible to the corresponding non-nullable type, the result type is the non-nullable equivalent of left.Type.

  • Otherwise, if right.Type is implicitly convertible to left.Type, the result type is left.Type.

  • Otherwise, if the non-nullable equivalent of left.Type is implicitly convertible to right.Type, the result type is right.Type.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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