How to find out if a property is an auto-implemented property with reflection?

So in my case i am doing discovery of the structure of a class using reflection. I need to be able to find out if a property is an auto-implemented property by the Pro开发者_运维问答pertyInfo object. I assume that the reflection API does not expose such functionality because auto-properties are C# dependent, but is there any workaround to get this information?

You could check to see if the get or set method is marked with the CompilerGenerated attribute. You could then combine that with looking for a private field that is marked with the CompilerGenerated attribute containing the name of the property and the string "BackingField".

Perhaps:

public static bool MightBeCouldBeMaybeAutoGeneratedInstanceProperty(
    this PropertyInfo info
) {
    bool mightBe = info.GetGetMethod()
                       .GetCustomAttributes(
                           typeof(CompilerGeneratedAttribute),
                           true
                       )
                       .Any();
    if (!mightBe) {
        return false;
    }


    bool maybe = info.DeclaringType
                     .GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
                     .Where(f => f.Name.Contains(info.Name))
                     .Where(f => f.Name.Contains("BackingField"))
                     .Where(
                         f => f.GetCustomAttributes(
                             typeof(CompilerGeneratedAttribute),
                             true
                         ).Any()
                     )
                     .Any();

        return maybe;
    }

It's not fool proof, quite brittle and probably not portable to, say, Mono.

This should do:

public static bool IsAutoProperty(this PropertyInfo prop)
{
    return prop.DeclaringType.GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
                             .Any(f => f.Name.Contains("<" + prop.Name + ">"));
}

The reason is that for auto-properties the Name property of the backing FieldInfo would look like:

<PropertName>k__BackingField

Since characters < and > wouldn't appear for normal fields, a field with that kind of naming points to a backing field of an auto-property. As Jason says, its brittle still.

Or to make it a tad faster,

public static bool IsAutoProperty(this PropertyInfo prop)
{
    if (!prop.CanWrite || !prop.CanRead)
        return false;

    return prop.DeclaringType.GetFields(BindingFlags.NonPublic | BindingFlags.Instance)
                             .Any(f => f.Name.Contains("<" + prop.Name + ">"));
}