Capturing values from a method call.

TryInvokeMember.cs

public override bool TryInvokeMember(
    InvokeMemberBinder binder,
    object[] args,
    out object result)
{            
    _props[binder.Name] = GetValue(args) ?? string.Empty;
    result = this;
    return true;
}

private string GetValue(object[] args)
{
    if (args.Length > 0)
    {
        var arg = args[0] as string;
        if (arg != null)
        {
            return arg;
        }
    }
    return null;
}