C# cast Dictionary to Dictionary (Involving Reflection)

ccastingreflection

Is it possible to cast a Dictionary<string, Anything> to a consistent intermediate generic type? So I would be able to cast <string, string>, <string, bool>, <string, int>, <string, anything> all to the same type of dictionary?

I am working on a project that is using heavy reflection and I need to be able to process DIctionary types as such:

FieldInfo field = this.GetType().GetField(fieldName);
Dictionary<string, Object> dict = (Dictionary<string, Object>)field.GetValue(this);

The above code is what I currently have and the program always fails at the cast from field.GetValue to the generic Dictionary<string, Object>.

Is there a way to do this? Or should I just figure out a different way to process these Dictionaries?

Any help would be greatly appreciated.

Best Answer

Following AakashM's answer, the Cast doesn't seem to play ball. You can get around it by using a little helper method though:

IDictionary dictionary = (IDictionary)field.GetValue(this);
Dictionary<string, object> newDictionary = CastDict(dictionary)
                                           .ToDictionary(entry => (string)entry.Key,
                                                         entry => entry.Value);

private IEnumerable<DictionaryEntry> CastDict(IDictionary dictionary)
{
    foreach (DictionaryEntry entry in dictionary)
    {
        yield return entry;
    }
}

The duck typing in foreach is handy in this instance.

Related Solutions

C# – Set object property using reflection

Yes, you can use Type.InvokeMember():

using System.Reflection;
MyObject obj = new MyObject();
obj.GetType().InvokeMember("Name",
    BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty,
    Type.DefaultBinder, obj, "Value");

This will throw an exception if obj doesn't have a property called Name, or it can't be set.

Another approach is to get the metadata for the property, and then set it. This will allow you to check for the existence of the property, and verify that it can be set:

using System.Reflection;
MyObject obj = new MyObject();
PropertyInfo prop = obj.GetType().GetProperty("Name", BindingFlags.Public | BindingFlags.Instance);
if(null != prop && prop.CanWrite)
{
    prop.SetValue(obj, "Value", null);
}

C# – Get property value from string using reflection

 public static object GetPropValue(object src, string propName)
 {
     return src.GetType().GetProperty(propName).GetValue(src, null);
 }

Of course, you will want to add validation and whatnot, but that is the gist of it.

Best Answer

Related Solutions

C# – Set object property using reflection

C# – Get property value from string using reflection

Related Topic