Question

Background

Working in .NET 2.0 Here, reflecting lists in general. I was originally using t.IsAssignableFrom(typeof(IEnumerable)) to detect if a Property I was traversing supported the IEnumerable Interface. (And thus I could cast the object to it safely)

However this code was not evaluating to True when the object is a BindingList<T>.

Next

I tried to use t.IsSubclassOf(typeof(IEnumerable)) and didn’t have any luck either.

Code

    /// <summary>
    /// Reflects an enumerable (not a list, bad name should be fixed later maybe?)
    /// </summary>
    /// <param name="o">The Object the property resides on.</param>
    /// <param name="p">The Property We're reflecting on</param>
    /// <param name="rla">The Attribute tagged to this property</param>
    public void ReflectList(object o, PropertyInfo p, ReflectedListAttribute rla)
    {
        Type t = p.PropertyType;
        //if (t.IsAssignableFrom(typeof(IEnumerable)))
        if (t.IsSubclassOf(typeof(IEnumerable)))
        {
            IEnumerable e = p.GetValue(o, null) as IEnumerable;

            int count = 0;
            if (e != null)
            {
                foreach (object lo in e)
                {
                    if (count >= rla.MaxRows)
                        break;

                    ReflectObject(lo, count);

                    count++;
                }
            }
        }
    }

The Intent

I want to basically tag lists i want to reflect through with the ReflectedListAttribute and call this function on the properties that has it. (Already Working)

Once inside this function, given the object the property resides on, and the PropertyInfo related, get the value of the property, cast it to an IEnumerable (assuming it’s possible) and then iterate through each child and call ReflectObject(...) on the child with the count variable.

Answer 1

When you do the as IEnumerable and the variable is not null you know that it does implement IEnumerable interface.

You don´t need the code:

Type t = p.PropertyType;
//if (t.IsAssignableFrom(typeof(IEnumerable)))
if (t.IsSubclassOf(typeof(IEnumerable)))
{

This would be enough:

public void ReflectList(object o, PropertyInfo p, ReflectedListAttribute rla)
{
    IEnumerable e = p.GetValue(o, null) as IEnumerable;

    int count = 0;
    if (e != null)
    {
        foreach (object lo in e)
        {
            if (count >= rla.MaxRows)
                break;
            ReflectObject(lo, count);
            count++;
        }
    }
}