Expression.Coalesce Method

Definition

Namespace:

System.Linq.Expressions

Assembly:

System.Linq.Expressions.dll

Creates a BinaryExpression that represents a coalescing operation.

Overloads

Coalesce(Expression, Expression, LambdaExpression)	Creates a BinaryExpression that represents a coalescing operation, given a conversion function.
Coalesce(Expression, Expression)	Creates a BinaryExpression that represents a coalescing operation.

Coalesce(Expression, Expression, LambdaExpression)

Source:

BinaryExpression.cs

Creates a BinaryExpression that represents a coalescing operation, given a conversion function.

public:
 static System::Linq::Expressions::BinaryExpression ^ Coalesce(System::Linq::Expressions::Expression ^ left, System::Linq::Expressions::Expression ^ right, System::Linq::Expressions::LambdaExpression ^ conversion);

public static System.Linq.Expressions.BinaryExpression Coalesce (System.Linq.Expressions.Expression left, System.Linq.Expressions.Expression right, System.Linq.Expressions.LambdaExpression? conversion);

static member Coalesce : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression * System.Linq.Expressions.LambdaExpression -> System.Linq.Expressions.BinaryExpression

Public Shared Function Coalesce (left As Expression, right As Expression, conversion As LambdaExpression) As BinaryExpression

Parameters

left

Expression

An Expression to set the Left property equal to.

right

Expression

An Expression to set the Right property equal to.

conversion

LambdaExpression

A LambdaExpression to set the Conversion property equal to.

Returns

BinaryExpression

A BinaryExpression that has the NodeType property equal to Coalesce and the Left, Right and Conversion properties set to the specified values.

Exceptions

ArgumentNullException

left or right is null.

ArgumentException

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

-or-

conversion is not null and conversion.Type is a delegate type that does not take exactly one argument.

InvalidOperationException

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

-or-

The Type property of left represents a type that is not assignable to the parameter type of the delegate type conversion.Type.

-or-

The Type property of right is not equal to the return type of the delegate type conversion.Type.

Remarks

The Method property of the resulting BinaryExpression is null and both IsLifted and IsLiftedToNull are set to false.

The Type property of the resulting BinaryExpression is equal to the result type of the coalescing operation.

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.

Coalesce(Expression, Expression)

Source:

BinaryExpression.cs

Creates a BinaryExpression that represents a coalescing operation.

public:
 static System::Linq::Expressions::BinaryExpression ^ Coalesce(System::Linq::Expressions::Expression ^ left, System::Linq::Expressions::Expression ^ right);

public static System.Linq.Expressions.BinaryExpression Coalesce (System.Linq.Expressions.Expression left, System.Linq.Expressions.Expression right);

static member Coalesce : System.Linq.Expressions.Expression * System.Linq.Expressions.Expression -> System.Linq.Expressions.BinaryExpression

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

Parameters

left

Expression

An Expression to set the Left property equal to.

right

Expression

An Expression to set the Right property equal to.

Returns

BinaryExpression

A BinaryExpression that has the NodeType property equal to Coalesce and the Left and Right properties set to the specified values.

Exceptions

ArgumentNullException

left or right is null.

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.

Remarks

The Method property of the resulting BinaryExpression is null 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 null.

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.

See also

• ?? Operator (C# Reference)