Get string name of property using reflection

Question

There is a whole wealth of reflection examples out there that allow you to get either:

1. All properties in a class

2. A single property, provided you know the string name

Is there a way (using reflection, TypeDescriptor, or otherwise) to get the string name of a property in a class at runtime, provided all I have is an instance of the class and property?

EDIT I know that I can easily get all the properties in a class using reflection and then get the name of each property. What I'm asking for is a function to give me name of a property, provided I pass it the instance of the property. In other words, how do I find the property I want from the PropertyInfo[] array returned to me from the class.GetType().GetProperty(myProperty) so that I can get the PropertyInfo.Name from it?

Answer 1

If you already have a PropertyInfo, then @dtb's answer is the right one. If, however, you're wanting to find out which property's code you're currently in, you'll have to traverse the current call stack to find out which method you're currently executing and derive the property name from there.

var stackTrace = new StackTrace();
var frames = stackTrace.GetFrames();
var thisFrame = frames[0];
var method = thisFrame.GetMethod();
var methodName = method.Name; // Should be get_* or set_*
var propertyName = method.Name.Substring(4);

Edit:

After your clarification, I'm wondering if what you're wanting to do is get the name of a property from a property expression. If so, you might want to write a method like this:

public static string GetPropertyName<T>(Expression<Func<T>> propertyExpression)
{
    return (propertyExpression.Body as MemberExpression).Member.Name;
}

To use it, you'd write something like this:

var propertyName = GetPropertyName(
    () => myObject.AProperty); // returns "AProperty"

Answer 2

With C# 6.0 (Visual Studio 2015), you can now use the nameof operator, like this:

var obj = new MyObject();
string propertyName = nameof(obj.Property);
string methodName = nameof(obj.Method);
string directPropertyName = nameof(MyObject.Property);
string directMethodName = nameof(MyObject.Method);

Answer 3

PropertyInfo.Name

Answer 4

In case anyone needs it...here is the VB .NET version of the answer:

Public Shared Function GetPropertyName(Of t)(ByVal PropertyExp As Expression(Of Func(Of t))) As String
   Return TryCast(PropertyExp.Body, MemberExpression).Member.Name
End Function

Usage:

Dim name As String = GetPropertyName(Function() (New myObject).AProperty)

Answer 5

acutully the right answer which is written by TKTS, and here I just want to convert his syntax to C#

public static string GetPropertyName<t>(Expression<Func<t>> PropertyExp)
{
return (PropertyExp.Body as MemberExpression).Member.Name;
}

and the usage of this code goes like the example as below:

string name = GetPropertyName(() => (new Tasks()).Title);

in addition : there is an exception could be happen that when the comes with all properties has null values, so anybody has to take this on his concentration when hes implementing his code

Thanks TKTS ..

Answer 6

myClassInstance.GetType().GetProperties() gives you PropertyInfo instances for all public properties for myClassInstance's type. (See MSDN for documentation and other overloads.) ´PropertyInfo.Name´ is the actual name of the property. In case you already know the name of the property use GetProperty(name) to retrieve its PropertyInfo object (see MSDN again).

Answer 7

I used the version provided by Jacob but sometimes it gave an exception. It was because the cast was invalid. This version solved the issue:

    public static string GetPropertyName<T>(this Expression<Func<T>> propertyExpression)
    {
        ConstantExpression cExpr = propertyExpression.Body as ConstantExpression;
        MemberExpression mExpr = propertyExpression.Body as MemberExpression;

        if (cExpr != null)
            return cExpr.Value.ToString();
        else if (mExpr != null)
            return mExpr.Member.Name;

        else return null;
    }