Get property name and type using lambda expression

Question

I am trying to write a function that will pull the name of a property and the type using syntax like below:

private class SomeClass {     Public string Col1; }  PropertyMapper<Somewhere> propertyMapper = new PropertyMapper<Somewhere>(); propertyMapper.MapProperty(x => x.Col1) 

Is there any way to pass the property through to the function without any major changes to this syntax?

I would like to get the property name and the property type.

So in the example below i would want to retrieve

Name = "Col1" and Type = "System.String"

Can anyone help?

Answer 1

Here's enough of an example of using Expressions to get the name of a property or field to get you started:

public static MemberInfo GetMemberInfo<T, U>(Expression<Func<T, U>> expression) {     var member = expression.Body as MemberExpression;     if (member != null)         return member.Member;      throw new ArgumentException("Expression is not a member access", "expression"); } 

Calling code would look like this:

public class Program {     public string Name     {         get { return "My Program"; }     }      static void Main()     {         MemberInfo member = ReflectionUtility.GetMemberInfo((Program p) => p.Name);         Console.WriteLine(member.Name);     } } 

A word of caution, though: the simple statment of (Program p) => p.Name actually involves quite a bit of work (and can take measurable amounts of time). Consider caching the result rather than calling the method frequently.

Answer 2

This can be easily done in C# 6. To get the name of property use nameof operator.

nameof(User.UserId) 

and to get type of property use typeof operator.

typeof(User.UserId)