GetParameterValue.cs

public static string GetParameterValue(this Parameter p)
        {
            if (p == null) return string.Empty;
            switch (p.StorageType)
            {
                case StorageType.Double:
                    return p.AsDouble().ToString();
                case StorageType.ElementId:
                    try
                    {
                        return p.AsElementId().IntegerValue.ToString();
                    }
                    catch (Exception)
                    {
                        return string.Empty;
                    }
                case StorageType.Integer:
                    return p.AsInteger().ToString();
                case StorageType.String:
                    return p.AsString();
                case StorageType.None:
                    return p.AsValueString();
            }
            return String.Empty;
        }