Expression for Type members results in different Expressions (MemberExpression, UnaryExpression)

by

The reason this happens is that Age is a value type. In order to coerce an expression returning a value type into Func<Person,object> the compiler needs to insert a Convert(expr, typeof(object)), a UnaryExpression.

For strings and other reference types, however, there is no need to box, so a “straight” member expression is returned.

If you would like to get to the MemberExpression inside the UnaryExpression, you can get its operand:

private static MemberExpression GetMemberExpression<T>(
    Expression<Func<T,object>> exp
) {
    var member = exp.Body as MemberExpression;
    var unary = exp.Body as UnaryExpression;
    return member ?? (unary != null ? unary.Operand as MemberExpression : null);
}

More Related Contents:

  1. lambda expression to sort on min values in a group
  2. converting a .net Func to a .net Expression
  3. Combining two expressions (Expression)
  4. delegate keyword vs. lambda notation
  5. Best and shortest way to evaluate mathematical expressions
  6. Can I specify my explicit type comparator inline?
  7. Lambda variable capture in loop – what happens here? [duplicate]
  8. Wrapping StopWatch timing with a delegate or lambda?
  9. Weak event handler model for use with lambdas
  10. How do I create an expression tree to represent ‘String.Contains(“term”)’ in C#?
  11. Pass expression parameter as argument to another expression
  12. Expression.Lambda and query generation at runtime, simplest “Where” example
  13. How do I pronounce “=>” as used in lambda expressions in .Net [closed]
  14. What is the Efficiency and Performance of LINQ and Lambda Expression in .Net?
  15. How to convert an expression tree to a partial SQL query?
  16. Get the name of a method using an expression
  17. Entity Framework – Cannot convert lambda expression to type ‘string’ because it is not a delegate type
  18. Expression of type ‘System.Int32’ cannot be used for return type ‘System.Object’
  19. LINQ – Query syntax vs method chains & lambda [closed]
  20. Peculiar overload resolution with while (true)
  21. How to unsubscribe from an event which uses a lambda expression?
  22. LINQ Expression to return Property value?
  23. Task.Factory.StartNew with async lambda and Task.WaitAll
  24. Why do some C# lambda expressions compile to static methods?
  25. What does “DisplayClass” name mean when calling lambda?
  26. Max return value if empty query
  27. Group by with multiple columns using lambda
  28. Getting names of local variables (and parameters) at run-time through lambda expressions
  29. Get the property name used in a Lambda Expression in .NET 3.5
  30. How to sort TreeView items using SortDescriptions in Xaml?

Leave a Comment