views:

855

answers:

4

C#, .NET 3.5

I am trying to get all of the properties of an object that have BOTH a getter and a setter for the instance. The code I thought should work is

PropertyInfo[] infos = source.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.GetProperty);

However, the results include a property that does not have a setter. To give you a simple idea of my inheritance structure that might be affecting this (though I don't know how):

public interface IModel
{
    string Name { get; }
}

public class BaseModel<TType> : IModel
{
    public virtual string Name { get { return "Foo"; } }

    public void ReflectionCopyTo(TType target)
    {
        PropertyInfo[] infos = this.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.GetProperty);
        foreach (PropertyInfo info in infos)
            info.SetValue(target, info.GetValue(this, null), null);
    }
}

public class Child : BaseModel<Child>
{
    // I do nothing to override the Name property here
}

I end up with the following error when working with Name:

System.ArgumentException: Property set method not found.

EDIT: I would like to know why this does not work, as well as what I should be doing to not get the error.

+5  A: 

Call GetGetMethod and GetSetMethod on the property - if both results are non-null, you're there :)

(The parameterless versions only return public methods; there's an overload with a boolean parameter to specify whether or not you also want non-public methods.)

Jon Skeet
But why doesn't the BindingFlags.SetProperty already doing that filtering? That's what I thought it was supposed to do.
Matt
@Matt: Because BindingFlags.SetProperty and BindingFlags.SetProperty are not used for look-up, they are used in other circumstances, Get Properties() method ignores those flags. Try without them you will get the same result.See supported flags: http://msdn.microsoft.com/en-us/library/kyaxdd3x.aspx
Pop Catalin
+1  A: 

This isn't supposed to work.

See definition of GetProperties on msdn for which is allowed:

The following BindingFlags filter flags can be used to define which nested types to include in the search:

* You must specify either BindingFlags.Instance or BindingFlags.Static in order to get a return.
* Specify BindingFlags.Public to include public properties in the search.
* Specify BindingFlags.NonPublic to include non-public properties (that is, private and protected members) in the search.
* Specify BindingFlags.FlattenHierarchy to include static properties up the hierarchy.

Or you can see the definition of GetProperty/SetProperty in msdn, which states that

GetProperty = Specifies that the value of the specified property should be returned.

SetProperty = Specifies that the value of the specified property should be set. For COM properties, specifying this binding flag is equivalent to specifying PutDispProperty and PutRefDispProperty.

+2  A: 

how about...

var qry = typeof(Foo).GetProperties(BindingFlags.Instance | BindingFlags.Public).Where(p => p.CanRead && p.CanWrite);
Tim Jarvis
+2  A: 

You can check the PropertyInfo.CanRead and PropertyInfo.CanWrite properties.

Matthieu DUFOURNEAUD-RAVEL