/// <summary>
/// Helper method to update the DefaultableValue if and only if the value has changed
/// </summary>
/// <param name="existingValue">
/// existing value of attribute (StringOrNone.NoneValue indicates attribute
/// currently does not exist)
/// </param>
/// <param name="newValue">
/// new value of attribute passed into setter (null indicates user did not select
/// anything on the drop-down and so no setting should take place, StringOrNone.NoneValue indicates user
/// selected '(None)' on the drop-down and so attribute should be removed if present)
/// </param>
/// <param name="defaultableValueToUpdate"></param>
internal static void UpdateDefaultableValueIfValuesDiffer(
StringOrNone existingValue, StringOrNone newValue,
DefaultableValue <StringOrNone> defaultableValueToUpdate)
{
if (null == newValue)
{
// user exited drop-down without selecting anything
return;
}
if (existingValue.Equals(newValue))
{
// no change in value - so just return
return;
}
else
{
// existingValue and valueToSet are different - so update the DefaultableValue
// if newValue is NoneValue then set valueToSet to null which will remove the attribute
// otherwise use newValue as is
var valueToSet = (StringOrNone.NoneValue.Equals(newValue) ? null : newValue);
var cmd =
new UpdateDefaultableValueCommand <StringOrNone>(defaultableValueToUpdate, valueToSet);
var cpc = PropertyWindowViewModelHelper.GetCommandProcessorContext();
CommandProcessor.InvokeSingleCommand(cpc, cmd);
}
}
protected override void InvokeInternal(CommandProcessorContext cpc)
{
if (_property == null)
{
throw new InvalidOperationException("InvokeInternal is called when _property is null.");
}
// if values are set to NoneValue then explictly remove the attribute,
// if values are set to null then leave the attribute as is
if (_theDefault != null)
{
_property.DefaultValue.Value = (_theDefault.Equals(StringOrNone.NoneValue) ? null : _theDefault);
}
if (_maxLength != null)
{
_property.MaxLength.Value = (_maxLength.Equals(DefaultableValueUIntOrNone.NoneValue) ? null : _maxLength);
}
if (_fixedLength != null)
{
_property.FixedLength.Value = (_fixedLength.Equals(BoolOrNone.NoneValue) ? null : _fixedLength);
}
if (_precision != null)
{
_property.Precision.Value = (_precision.Equals(DefaultableValueUIntOrNone.NoneValue) ? null : _precision);
}
if (_scale != null)
{
_property.Scale.Value = (_scale.Equals(DefaultableValueUIntOrNone.NoneValue) ? null : _scale);
}
if (_unicode != null)
{
_property.Unicode.Value = (_unicode.Equals(BoolOrNone.NoneValue) ? null : _unicode);
}
if (_collation != null)
{
_property.Collation.Value = (_collation.Equals(StringOrNone.NoneValue) ? null : _collation);
}
if (_concurrencyMode != null)
{
_property.ConcurrencyMode.Value = _concurrencyMode;
}
}