Access a nested structure by path (i.e., "Model.NestedModel.ListOfThings[1]")

Given the following classes and data:

public class InnerExample
{
    public string Inner1 { get; set; }
}


public class Example
{
    public string Property1 { get; set; }
    public string Property2 { get; set; }
    public List<InnerExample> Inner { get; set; }
}

var a = new Example
{
    Property1 = "Foo",
    Property2 = "Bar",
    Inner = new List<InnerExample>
    {
      new InnerExample
      {
        Inner1 = "This is the value to change"
      }
   }
};

Is there any way to access the innermost data by path?

Is there any way to say...

a["Inner[0].Inner1"] = "New value"

In this particular case, I know for a fact that I will never be accessing a key that does not exist, so I'm not overly concerned about error checking.

(Sorry if this has been asked before. I did a few searches but quickly ran out of keywords to try.)

Solution

Thanks to the basic advice you gave me, Jon, I came up with a solution that works for my case.

There is no error checking
You must be setting a property, not an array element.

I'm sure there are more efficient ways to do this... I'm far from an expert on reflection.

/// <summary>
/// Take an extended key and walk through an object to update it.
/// </summary>
/// <param name="o">The object to update</param>
/// <param name="key">The key in the form of "NestedThing.List[2].key"</param>
/// <param name="value">The value to update to</param>
private static void UpdateModel(object o, string key, object value)
{
    // TODO:
    // Make the code more efficient.

    var target = o;
    PropertyInfo pi = null;

    // Split the key into bits.
    var steps = key.Split('.').ToList();

    // Don't walk all the way to the end
    // Save that for the last step.
    var lastStep = steps[steps.Count-1];
    steps.RemoveAt(steps.Count-1);

    // Step through the bits.
    foreach (var bit in steps)
    {
        var step = bit;

        string index = null;

        // Is this an indexed property?
        if (step.EndsWith("]"))
        {
            // Extract out the value of the index
            var end = step.IndexOf("[", System.StringComparison.Ordinal);
            index = step.Substring(end+1, step.Length - end - 2);

            // and trim 'step' back down to exclude it.  (List[5] becomes List)
            step = step.Substring(0, end);
        }

        // Get the new target.
        pi = target.GetType().GetProperty(step);
        target = pi.GetValue(target);

        // If the target had an index, find it now.
        if (index != null)
        {
            var idx = Convert.ToInt16(index);

            // The most generic way to handle it.
            var list = (IEnumerable) target;
            foreach (var e in list)
            {
                if (idx ==0)
                {
                    target = e;
                    break;
                }
                idx--;
            }
        }
    }

    // Now at the end we can apply the last step,
    // actually setting the new value.
    if (pi != null || steps.Count == 0)
    {
        pi = target.GetType().GetProperty(lastStep);
        pi.SetValue(target, value);
    }
}