[Solved] Custom column not updating and showing bad data for rows - painting issue?

[Roger]

I have a RadDataGrid that I am using that has a custom column. This column shows a warning image if another column's value is 0. I am noticing that the first render of the grid is correct - the indicators only show on rows which should show this warning indicator. However, if I start scrolling the list, many more of these indicators appear, and when I scroll back to the top of the list the indicator is drawn on every single row.

This looks like a painting issue. Like I said, the grid shows the indicator correctly until you start scrolling it and come back to the top. I can also confirm that this worked properly on the GridView I was using with this same binding prior.

Here is the column in question. For what it's worth, replacing the image indicator with text instead has the same issue - the text starts showing on all rows after a bit of scrolling.

<telerikGrid:DataGridTemplateColumn Header="">
  <telerikGrid:DataGridTemplateColumn.CellContentTemplate>
    <DataTemplate>
        <Image Source="ms-appx:///Assets/WarningIcon28White.png"
               Width="28"
               Height="28"
               Margin="8,-12,8,0"
               Visibility="{Binding Quantity, Converter={StaticResource visCvt}, ConverterParameter=Reverse}"
               VerticalAlignment="Center"
               HorizontalAlignment="Left" />
    </DataTemplate>
  </telerikGrid:DataGridTemplateColumn.CellContentTemplate>
</telerikGrid:DataGridTemplateColumn>

[jasonxz]

I have also noticed this is a problem with the new DataGridImageColumn.

 

[Ivaylo Gergov]

Hi Roger,

Thank you for contacting us.

The UI Virtualization of RadDataGrid overrides both the Visibility and the Opacity properties of the element that represents each cell. For your scenario I can suggest two options:

• Use the Converter for the Image.Source property instead of the Image.Visibility property and return null when the image should not be visible.
• Put the Image in a Border element. Thus, RadDataGrid will override the Border.Visibility and the Border.Opacity properties and it will not affect the Image.

I hope this is useful. Let me know if I can assist you further.


Regards,
Ivaylo Gergov
Telerik

[Roger]

Thanks, adding a border did fix it!

Thanks again,
-roger