@akramkamil-9845 Do you mean that the Mandaic not in the Office supported language list ?You add the windows-wpf tag, if your question related to it, could you please give some info about it?

The previous console didn't have anything marked in red, and I wanted to keep it simple。

Thanks for your help, I want to know the reason why <DataGridTextColumn Header="FontSize" Width="80" Binding="{Binding FontSize}" Foreground="{Binding ForeColor}"/> doesn't work. Do you know the reason? Thanks in advance.

Thanks for your reply.
My Web Browser configuration page is same as the picture which you provided above. And http://go.microsoft.com/fwlink/?LinkId=625115 for Internet Explorer Options.... Home Tab. But it not work well. Is there anything I missed?

@JustHPS-9250
Did you solve your issue? If you didn't, could you provide more detailed info what like vb2ae refered?

@TamBui-8699
I make a .Net core 3.1 app following your question description in my Visual Studio Enterprise 2019, but my app run well without the error you got. Did you run your Visual Studio as Administrator? By the way, my setting of User Account Control Settings is default, what is yours?

@RONALDBEAUMAN-1773
Did you meet the same error when you run your new project? Sometimes Visual studio can't recognized without buiding the project.

@ MERUNKUMARMAITY-4120
There is a demo on How to: Produce a Value Based on a List of Bound Items showing you how to use ConverterParameter, it may give you some help.

@MERUNKUMARMAITY-4120
TextBlock.FontSize Property is a double type not string, you couldn't bind a string to it. MultiBinding: Using Converter gives you a good example to learning MultiBinding. By the way, I don't think it is a good way to bind same element with same path in MultiBinding.

@MERUNKUMARMAITY-4120
Do you want to choose one of the FontSize in the MultiBinding for your Button? If you do, how about adding ConverterParameter for MultiBinding as the Parameter to choose the Font?

@StoutGamer
I didn't find any code of RangeMin and RangeMax, so I remove them to test. Then when I used local:JustPositivDecimalInput="False" to replace JustPositiveDecimalInput="False" in your xaml, the project works well.

@StoutGamer
I use your code in my WPF .netcore 5 app and it runs without error . Did your project meet the Dependencies as below shown of the NuGet package?

@StoutGamer
I can't reproduce your error with the above the code. Could you show the code of TextBoxInputBehavior for me to make a sample in Framework4.7.2 to reproduce your error?

@BalamuruganRajaraman-1884
Could you give some info of your RelayCommand? Did you install any package of Microsoft.Toolkit.Mvvm or MvvmLightLibs? If you create RelayCommand on yourself, please show me the related code.

@GurpreetSingh-0643
Could you try to set your RenderOptions.ProcessRenderMode to be SoftwareOnly to try? If it doesn't work, plase show some code sinppet of your popup for me to make a demo to reproduce your error.