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[Solved] Blank grid after rows deleted

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GridView

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Robert Smyth asked on 20 Oct 2010, 06:01 AM

Hi,

I'm using RadGridView in an application were user selections on the page change the number of rows in the grid. When viewing the last 30 rows in a grid of 100 rows and the last 60 rows are removed from the grid we see a blank grid with the now last row visible at the bottom. If we click on a column header it refreshes and all rows are visible. The scroll bar is correctly indicating 30 rows.

How can I remove rows and have the grid display the remaining rows?

The grid XAML is:

<Controls:RadGridView Name="myTable"

Grid.Row="0" Width="Auto" Height="Auto" MinHeight="150"

GroupPanelBackground="LightGray"

GroupPanelForeground="LightGray"

VerticalGridLinesBrush="Transparent"

HeaderRowStyle="{StaticResource HeaderRowStyle}"

GridLinesVisibility="None"

RowIndicatorVisibility="Collapsed"

DataLoadMode="Asynchronous"

EnableRowVirtualization="True"

EnableColumnVirtualization="True"

AlternationCount="2"

SelectionMode="Extended"

AutoGenerateColumns="False"

ItemsSource="{Binding Mode=OneWay,Path=MyData}"

IsReadOnly="True"

CanUserResizeColumns="True"

IsFilteringAllowed="False"

CanUserSortColumns="True"

AllowDrop="False"

ShowGroupPanel="False"

ShowInsertRow="False"

VerticalAlignment="Top"

DataLoaded="MyTableDataLoaded"

ColumnWidth="Auto"

CanUserInsertRows="False"

CanUserDeleteRows="False"

CanUserFreezeColumns="False"

CanUserReorderColumns="False"

SelectionChanged="MyTableSelectionChanged">

<Controls:RadGridView.Columns>

<Controls:GridViewDataColumn HeaderCellStyle="{StaticResource HeaderCellStyle}" Header="Date" DataMemberBinding="{Binding Path=TimeStamp,StringFormat=dd/MM}"/>

<Controls:GridViewImageColumn HeaderCellStyle="{StaticResource HeaderCellStyle}" Header="AAA" DataMemberBinding="{Binding AAA,Converter={StaticResource AAAToImageConverter}}" ImageHeight="12" />

<Controls:GridViewDataColumn HeaderCellStyle="{StaticResource HeaderCellStyle}" Header="BBB" DataMemberBinding="{Binding BBB,StringFormat=N0}" TextAlignment="Right"/>

<Controls:GridViewDataColumn HeaderCellStyle="{StaticResource HeaderCellStyle}" Header="CCC" DataMemberBinding="{Binding CCC,StringFormat=N0}" TextAlignment="Right"/>

</Controls:RadGridView.Columns>

</Controls:RadGridView>

In the data loaded handler we do call 'ScrollIntoView' to ensure that the last row is visible.

Any ideas?

Rob Smyth

15 Answers, 1 is accepted

answered on 12 Nov 2010, 08:53 AM

radgridview-sl4-ar-16.zip

Hello Robert Smyth,

I am attaching my sample project where the problem cannot be reproduced with Q3 2010 assemblies. Please, feel free to modify it in order to demonstrate it.

Best wishes,
Yordanka
the Telerik team

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answered on 12 May 2011, 06:07 PM

I am using the May 2nd internal release .dlls.

I am seeing a problem similar to what was described above. I have a grid with a vertical scrollbar.
If I
select an item in the middle of the grid
scroll to the bottom so the selected item is out of view
and select the last item in the grid while holding shift, so I select all the items in between.

Then I hit a delete button and the grid does not update properly, it appears blank until I click on the column headers to update the sorting.

Here are the changes in made to your attached project above(RadGridView_SL4_AR_16).

I changed the Delete button click logic.

private void Button1_Click(object sender, RoutedEventArgs e)

{

IEnumerable<DataItem> dataEnumerable = (IEnumerable<DataItem>)this.myTable.ItemsSource;

List<DataItem> dataList = dataEnumerable.ToList();

foreach (DataItem curData in this.myTable.SelectedItems ) {

dataList.Remove(curData);

}

this.myTable.ItemsSource = dataList;

}

private void MyTableDataLoaded(object sender, EventArgs e)

{

// this.myTable.ScrollIntoView(this.myTable.Items[this.myTable.Items.Count - 1]);

}

And I commented out the DataLoadMode, and set EnableColumnVirtualization="False"

<telerik:RadGridView Name="myTable" Grid.Row="0" Width="Auto" Height="Auto" MinHeight="150"

GroupPanelBackground="LightGray"

GroupPanelForeground="LightGray"

VerticalGridLinesBrush="Transparent"

GridLinesVisibility="None"

RowIndicatorVisibility="Collapsed"

EnableRowVirtualization="True"

EnableColumnVirtualization="False"

AlternationCount="2"

SelectionMode="Extended"

AutoGenerateColumns="False"

ItemsSource="{Binding Mode=OneWay,Path=MyData}"

IsReadOnly="True"

CanUserResizeColumns="True"

IsFilteringAllowed="False"

CanUserSortColumns="True"

AllowDrop="False"

ShowGroupPanel="False"

ShowInsertRow="False"

VerticalAlignment="Top"

DataLoaded="MyTableDataLoaded"

ColumnWidth="Auto"

CanUserInsertRows="False"

CanUserDeleteRows="False"

CanUserFreezeColumns="False"

CanUserReorderColumns="False"

SelectionChanged="MyTableSelectionChanged">

answered on 16 May 2011, 11:58 AM

Hello,

The best approach to delete items on button click is by using Delete command as demonstrated on this example:

<telerik:RadButton Name="Button1"

Content="Delete"

Command="telerik:RadGridViewCommands.Delete"

CommandTarget="{Binding ElementName=myTable}"

Margin="5"

HorizontalAlignment="Left"/>

Let us know in case this approach is not acceptable for you or your requirements are different.

Best wishes,
Yordanka
the Telerik team

answered on 21 Jul 2011, 07:35 PM

I am using Telerik.Windows.Controls.GridView.dll version 2011.1.419.35 and I am also seeing this problem.

I am able to reproduce it easily with these steps:
1) Scroll to the bottom of a large list of items
2) Delete X (where X >= 2) items from the item collection that the RadGridView's ItemSource is bound to. This results in X-1 blank rows at the top of the RadGridView window
3) Clicking on the RadGridView or scrolling will cause it to update and correct the problem.

I have also verified that this only happens when I have EnableRowVirtualization set to True.