C# Using the Dynamic keyword to access properties via strings without reflection

I would like to write something similar to the following:

//  I will pass in a number of "properties" specified as strings that I want modified
string[] properties = new [] { "AllowEdit", "AllowDelete" };

//  Casting the component I'm using to a dynamic object of some sort ?
dynamic d = myGridComponent;

//  Iterate over the strings and set the properties
foreach(var s in properties) 
{
  //d.s = true; // 
  //d[s] = true; // this format would be ideal
}

I was wondering if there was an easy way to do this without using Reflection [.GetProperty(...).GetValue(...,...)] using the new C# 4.0 keyword: dynamic.

It seems that there may be some way, ... I'm just not sure of the exact mechanism, and haven't been able to find the right resource to put开发者_StackOverflow社区 all the pieces together.

Thoughts ?

[EDIT] It looks like there is a package called "Clay" that implements this type of functionality in some way. Clay on CodePlex

Scott Hanselman on the Subject

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It can be done. You just have to override TryGetIndex on DynamicObject. I needed something similar to invoke static members of a type, but hopefully you will get the idea. Mind you this does not currently work on methods with generic type arguments or methods that are overloaded, limiting its utility:

internal class StaticMembersDynamicWrapper : DynamicObject
{
    private readonly IDictionary<String, MemberInfo> staticMembers = new Dictionary<string, MemberInfo>();
    private readonly Type type;

    public StaticMembersDynamicWrapper(Type type)
    {
        this.type = type;
        type.GetMembers(BindingFlags.FlattenHierarchy | BindingFlags.Static | BindingFlags.Public)
            .Each(member => staticMembers[member.Name] = member);
    }

    public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result)
    {
        var name = indexes[0] as string;

        MemberInfo member;

        if (false == staticMembers.TryGetValue(name, out member))
        {
            result = null;
            return false;
        }

        var prop = member as PropertyInfo;
        if (prop != null)
        {
            result = prop.GetValue(null, null);
            return true;
        }
        var method = member as MethodInfo;
        if (method != null)
        {
            var parameterTypes = (from p in method.GetParameters()
                                  select p.ParameterType).ToArray();
            var delegateType = method.ReturnType != typeof (void)
                            ? Expression.GetFuncType(parameterTypes.Union(new[]{method.ReturnType}).ToArray())
                            : Expression.GetActionType(parameterTypes);
            result = Delegate.CreateDelegate(delegateType, method);
            return true;
        }
        result = null;
        return false;
    }
}

dynamic d = new StaticMembersDynamicWrapper(typeof(string));
var result = d["IsNullOrEmpty"](String.Empty);

---

No. dynamic in C# doesn't offer that. With your two examples:

d.s = true; // this looks for a property or field called "s"
d[s] = true; // this looks for an indexer that matches the string/bool signature

You can write the same code that dynamic offers, but it would be a lot harder than just using reflection. Either use reflection (as per your example), or if you need to optimise it you can optionally wrap it in a delegate, via either Expression or Delegate.CreateDelegate.

---

The opensource framework Impromptu-interface available via nuget encapsulates the code that dynamic would generate in a fully dynamic fashion. It's not as fast as using the dynamic keyword, but is faster than reflection.

foreach(var s in properties) 
{
  //d.s = true; 
  Impromptu.InvokeSet(d, s, true);
}