add render transfrom in code behind

Question

hi
here is an attached property i've created to add TranslateTransform to any control:

 public static string GetSetRanderTransformTranslateProperty(DependencyObject obj)
          => (string)obj.GetValue(SetRanderTransformTranslateProperty);
        public static void SetSetRanderTransformTranslateProperty(DependencyObject obj, string value)
            => obj.SetValue(SetRanderTransformTranslateProperty, value);
        // Using a DependencyProperty as the backing store for SetRanderTransformRotateProperty.  This enables animation, styling, binding, etc...
        public static readonly DependencyProperty SetRanderTransformTranslateProperty =
            DependencyProperty.RegisterAttached("SetRanderTrasformTranslateProperty", typeof(string), typeof(GeneralBehaviors)
                , new PropertyMetadata("0,0", OnRanderTransformTranslatePropertyChanged));

        private static void OnRanderTransformTranslatePropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var element = d as FrameworkElement;

            if (element == null /*|| !(e.NewValue is string)*/) return;

            element.Loaded += (s, ea) =>
            {
                var value = ((string)e.NewValue).Trim().Split(new char[] { ',', ' ' });

                if (value.Length != 2) return;
                if (double.TryParse(value[0], out double dx) &&
                    double.TryParse(value[1], out double dy))
                {
                    element.RenderTransformOrigin = new Point(0.5, 0.5);
                    TranslateTransform translate = new TranslateTransform(dx, dy);
                    element.RenderTransform = translate;
                }
                else return;
            };


        }

the problem is when i'm trying to apply ScaleTransform attached property (created the same way) to the same control it cancels the previous translateTransform.
the problem is i don't know if control.RenderTransform property is a TransfromGroup or just Transform and the check if (control.RenderTransform is TransformGroup) and if (control.RenderTransform is Transform) aren't help because RenderTransform can refer to both.
how do we solve this problem.
any help will be appreciated, thanks in advance.

i'm using VS2019 , C#, wpf .net core3.1 application.

Answer 1

From Dependency Property Setting Precedence List, your SetRanderTransformTranslateProperty is higher than control's RenderTransform, to prevent ScaleTransform from being overwritten by TranslateTransform, you can set it in under LayoutTransform. Take CheckBox using your SetRanderTransformTranslateProperty as an example:

 <CheckBox  Width="130" Height="30" Content="Click Yellow" Background="Yellow" local:GeneralBehaviors.SetRanderTransformTranslateProperty="60,60"></CheckBox>  
  
         
        <CheckBox Width="130" Height="30" Content="Click green" Background="Green" local:GeneralBehaviors.SetRanderTransformTranslateProperty="60,60">  
            <CheckBox.LayoutTransform>  
                <ScaleTransform ScaleX="5"  ScaleY="5"></ScaleTransform>  
            </CheckBox.LayoutTransform>  
        </CheckBox>  

and the result picture is：

If I misunderstand your question,please point out.

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