Accessing object property as string and setting it

Question

I have an instance of the Account class. Each account object has an owner, reference, etc.

One way I can access an accounts properties is through accessors like

account.Reference;

but I would like to be able to access it using dynamic string selectors like:

account["PropertyName"];

just like in JavaScript. So I would have account["Reference"] which would return the value, but I also would like to be able to assign a new value after that like:

account["Reference"] = "124ds4EE2s";

I've noticed I can use

DataBinder.Eval(account,"Reference") 

to get a property based on a string, but using this I can't assign a value to the property.

Any idea on how I could do that?

Answer 1

I personally prefer to work with extension methods so here is my code :

public static class ReflectionExtensions
{
    public static void SetPropertyValue(this object Target,
        string PropertyName,
        object NewValue)
    {
        if (Target == null) return; //or throw exception

        System.Reflection.PropertyInfo prop = Target.GetType().GetProperty(PropertyName);

        if (prop == null) return; //or throw exception

        object value = prop.GetValue(Target, null);

        prop.SetValue(Target, NewValue, null);
    }
}

Answer 2

I agree with the previous posters that you probably do need to be using the properties. Reflection is very slow compared to direct property access.

On the other hand, if you need to maintain a list of user-defined properties, then you can't use C# properties. You need to pretend you are a Dictionary, or you need to expose a property that behaves like a Dictionary. Here is an example of how you could make the Account class support user-defined properties:

public class Account
{
    Dictionary<string, object> properties;
    public object this[string propertyName]
    {
        get
        {
            if (properties.ContainsKey[propertyName])
                return properties[propertyName];
            else
                return null;
        }
        set
        {
            properties[propertyName] = value;
        }
    }
}