I've struggled on and off getting the DataGrid to behave the way I expect. I've gone through this forum and made several changes based on related questions, but I still have some issues.
The biggest one I have now is the visibility of items when navigating around the App.
I whittled down the "HomePage" to just the DataGrid and some buttons. In the App I normally refresh this DataGrid when the page is navigated to. For simplicity's sake, I do it manually in this example. Because the HomePage is on the Navigation stack, I expect the Page and the ViewModel to remain valid and thus the items in the DataGrid to still be there, even if I don't refresh the data source. when I return to the page. See the images below and attached video example.
For additional context, I am using NavigationPages and Dependency Injection (for the Pages and ViewModels) to navigate (not AppShell).
<Grid RowDefinitions="*,100">
<telerik:RadDataGrid x:Name="grdRegisters"
RowHeight="50"
Style="{StaticResource ReadOnlyGridStyle}"
ItemsSource="{Binding Registers}"
SelectionStyle="{StaticResource SelectedRowBackgroundStyle}"
RowBackgroundStyle="{StaticResource RowBackgroundStyle}"
AlternateRowBackgroundStyle="{StaticResource AltRowBackgroundStyle}"
SelectedItem="{Binding SelectedRegister, Mode=TwoWay}">
<telerik:RadDataGrid.Columns>
<telerik:DataGridTemplateColumn HeaderText=""
SizeMode="Fixed"
Width="50">
<telerik:DataGridTemplateColumn.CellContentTemplate>
<DataTemplate x:DataType="RegisterModel">
<Label FontFamily="FASolid"
HorizontalOptions="Center"
VerticalOptions="Center"
Text=""
IsVisible="{Binding IsCurrentRegister, Mode=OneTime}"/>
</DataTemplate>
</telerik:DataGridTemplateColumn.CellContentTemplate>
</telerik:DataGridTemplateColumn>
<telerik:DataGridTemplateColumn HeaderText="Shift Date">
<telerik:DataGridTemplateColumn.CellContentTemplate>
<DataTemplate x:DataType="RegisterModel">
<Label Style="{StaticResource GridCellLabelStyle}"
Text="{Binding Date, Converter={StaticResource ToLocalTimeConverter}, StringFormat='{}{0:d}'}"/>
</DataTemplate>
</telerik:DataGridTemplateColumn.CellContentTemplate>
</telerik:DataGridTemplateColumn>
<telerik:DataGridTemplateColumn HeaderText="Shift Name">
<telerik:DataGridTemplateColumn.CellContentTemplate>
<DataTemplate x:DataType="RegisterModel">
<Label Style="{StaticResource GridCellLabelStyle}"
Text="{Binding Shift.Name}"/>
</DataTemplate>
</telerik:DataGridTemplateColumn.CellContentTemplate>
</telerik:DataGridTemplateColumn>
<telerik:DataGridTemplateColumn HeaderText="Start Time">
<telerik:DataGridTemplateColumn.CellContentTemplate>
<DataTemplate x:DataType="RegisterModel">
<Label Style="{StaticResource GridCellLabelStyle}"
Text="{Binding StartTime, Converter={StaticResource ToLocalTimeConverter}, StringFormat='{}{0:t}'}"/>
</DataTemplate>
</telerik:DataGridTemplateColumn.CellContentTemplate>
</telerik:DataGridTemplateColumn>
<telerik:DataGridTemplateColumn HeaderText="End Time">
<telerik:DataGridTemplateColumn.CellContentTemplate>
<DataTemplate x:DataType="RegisterModel">
<Label Style="{StaticResource GridCellLabelStyle}"
Text="{Binding EndTime, Converter={StaticResource ToLocalTimeConverter}, StringFormat='{}{0:t}'}"/>
</DataTemplate>
</telerik:DataGridTemplateColumn.CellContentTemplate>
</telerik:DataGridTemplateColumn>
</telerik:RadDataGrid.Columns>
</telerik:RadDataGrid>
<HorizontalStackLayout Grid.Row="1">
<Button Text="Resume"
IsEnabled="{Binding SelectedRegister, Converter={StaticResource IsNotNullConverter}}"
Command="{Binding ResumeShiftCommand}"/>
<Button Text="Refresh"
Command="{Binding RefreshCommand}"/>
</HorizontalStackLayout>
</Grid>
On initial Refresh, all items are visible in the DataGrid
I navigate forward and then back (PopToRoot), the DataGrid appears empty, although the vertical scroll appears like there are items.
If I tap Refresh, items become visible, but only above the first fold.
If i resize the window vertically, items will appear and disappear depending on the height of the window. (see attached video)
1 Answer, 1 is accepted
Hello Derrick,
I have tested the code in a sample app and managed to reproduce. It looks like the problem comes from using the PopToRootAsync method. I have logged an issue on your behalf which you can follow and be notified about its status from the following link:
https://feedback.telerik.com/maui/1576599-datagrid-winui-items-do-not-invalidate-correctly-when-changing-pages
Workaround
The only solution I can currently offer is using the Navigation.PushAsync instead of PopToRootAsync, as the issue occurs only with the PopToRootAsync method.
I hope this information helps. Let me know if I can provide any further assistance.
Regards,
Antoan
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