System.Linq.Expressions.LogicalBinaryExpression类有什么问题？

Question

I'm trying to parse Expression and at some point I have to parse expressions with type System.Linq.Expressions.LogicalBinaryExpression . This class name I take from debug watch. expression.GetType().ToString() equals "System.Linq.Expressions.LogicalBinaryExpression" . But I cant see this class in System.Linq.Expressions namespace. Nowhere at all. The same thing with MethodBinaryExpression class.

In order to check type I really prefer to write

• expression is LogicalBinaryExpression or
• expression.GetType() = typeof(LogicalBinaryExpression ) but definitely not
• expression.GetType().ToString() == "System.Linq.Expressions.LogicalBinaryExpression"

So now I just have error

The type or namespace name 'LogicalBinaryExpression' does not exist in the namespace 'System.Linq.Expressions' (are you missing an assembly reference?)

How this possible?

Answer 1

LogicalBinaryExpression is internal , so:

1. It's more difficult to get is as a Type , you can't simply use typeof(LogicalBinaryExpression) or x is LogicalBinaryExpression .
2. You won't find any documentation about it.
3. You shouldn't use it at all. It's an implementation detail that can change any time.

You should either check for BinaryExpression , or check the NodeType of the expression.

The same applies to MethodBinaryExpression .