Expression.Coalesce Method (Expression, Expression, LambdaExpression)
Creates a BinaryExpression that represents a coalescing operation, given a conversion function.
Assembly: System.Core (in System.Core.dll)
public static BinaryExpression Coalesce( Expression left, Expression right, LambdaExpression conversion )
left or right is null.
left.Type and right.Type are not convertible to each other.
conversion is not null and conversion.Type is a delegate type that does not take exactly one argument.
The Type property of left does not represent a reference type or a nullable value type.
The Type property of left represents a type that is not assignable to the parameter type of the delegate type conversion.Type.
The Type property of right is not equal to the return type of the delegate type conversion.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.