Expression.AndAlso Method (Expression, Expression, MethodInfo)
Creates a BinaryExpression that represents a conditional AND operation that evaluates the second operand only if the first operand is resolved to true. The implementing method can be specified.
Assemblies: System.Core (in System.Core.dll)
System.Linq.Expressions (in System.Linq.Expressions.dll)
'Declaration Public Shared Function AndAlso ( _ left As Expression, _ right As Expression, _ method As MethodInfo _ ) As BinaryExpression
left or right is Nothing.
method is not Nothing and the method it represents returns void, is not static (Shared in Visual Basic), or does not take exactly two arguments.
method is Nothing and the bitwise AND operator is not defined for left.Type and right.Type.
method is Nothing and left.Type and right.Type are not the same Boolean type.
The resulting BinaryExpression has the Method property set to the implementing method. The Type property is set to the type of the node. If the node is lifted, the IsLifted and IsLiftedToNull properties are both true. Otherwise, they are false. The Conversion property is Nothing.
The following information describes the implementing method, the node type, and whether a node is lifted.
The implementing method for the operation is chosen based on the following rules:
If method is not Nothing and it represents a non-void, static (Shared in Visual Basic) method that takes two arguments, it is the implementing method for the node.
The conditional AND operator cannot be overloaded in C# or Visual Basic. However, the conditional AND operator is evaluated by using the bitwise AND operator. Thus, a user-defined overload of the bitwise AND operator can be the implementing method for this node type.
Otherwise, if left.Type and right.Type are Boolean types, the implementing method is Nothing.
If the implementing method is not Nothing:
If left.Type and right.Type are assignable to the corresponding argument types of the implementing method, the node is not lifted. The type of the node is the return type of the implementing method.
If the following two conditions are satisfied, the node is lifted and the type of the node is the nullable type that corresponds to the return type of the implementing method:
left.Type and right.Type are both value types of which at least one is nullable, and the corresponding non-nullable types are equal to the corresponding argument types of the implementing method.
The return type of the implementing method is a non-nullable value type.
If the implementing method is Nothing:
left.Type and right.Type are the same Boolean type.
If left.Type and right.Type are non-nullable, the node is not lifted. The type of the node is the result type of the predefined conditional AND operator.
If left.Type and right.Type are nullable, the node is lifted. The type of the node is the nullable type that corresponds to the result type of the predefined conditional AND operator.