public PropQueryParameters AddSingleValue(string name, string value)
{
if (value == null)
return this;
if (Value != null && Value.Any(v => v.Name == name))
throw new InvalidOperationException(
string.Format("Tried adding value with the name '{0}' that is already present.", name));
var result = new PropQueryParameters(PropName);
CopyTo(result);
result.Value = new NameValueParameter(Value, name, value);
return result;
}