How to Get DataGrid Rows after updating ItemsSource in wpf?

Question

In my application, there is a datagrid that include listbox as the datagrid Cell.After updating the datagrid ItemsSource,I want to also update the listbox itemsSource.

private void DataUpdate()
if (_dtWorkTime.Rows.Count > 0)
{
     taskDetailGrid.ItemsSource = _dtWorkTime.DefaultView;
     taskDetailGrid.Items.Refresh();
     taskDetailGrid.UpdateLayout();
     LisBoxDataUpdate(SelectContacts);
}

As the above, after updating the datagrid ItemsSource, also update to the itemssource of the listbox that is datagrid cell.

private void LisBoxDataUpdate(ObservableCollection<ContactInfo> SelectContacts)
        {
            if (SelectContacts != null)
            {
                var row_list = GetDataGridRows(taskDetailGrid);
                foreach (DataGridRow single_row in row_list)
                {
                    if (single_row == null) break;
                    if (single_row.IsSelected == true)
                    {
                        ListBox memberGrid = FindChild<ListBox>(single_row, "memberListBox");
                        memberGrid.ItemsSource = SelectContacts;

                        Button btnMemberAdd = FindChild<Button>(single_row, "btnMemberAdd");

                        if (SelectContacts.Count <= 0)
                        {
                            memberGrid.Visibility = Visibility.Hidden;
                            btnMemberAdd.Visibility = Visibility.Visible;
                        }
                        else
                        {
                            memberGrid.Visibility = Visibility.Visible;
                            btnMemberAdd.Visibility = Visibility.Hidden;
                        }
                        break;
                    }
                }
            }
        }

public IEnumerable<DataGridRow> GetDataGridRows(DataGrid grid)
        {
            var itemsSource = grid.ItemsSource as IEnumerable;

            if (null == itemsSource)
            {
                yield return null;
            }

            foreach (var item in itemsSource)
            {
                var row = grid.ItemContainerGenerator.ContainerFromItem(item) as DataGridRow;
                if (null != row)
                {
                    yield return row;
                }
            }
        }

XAML code is as the following.

<DataGrid x:Name="taskDetailGrid" Margin="0,0,-0.333,0.333" VerticalScrollBarVisibility="Hidden"
                  HorizontalScrollBarVisibility="Hidden" HeadersVisibility="None" RowHeight="80"
                  AutoGenerateColumns="False" CanUserAddRows="False" BorderThickness="1" Background="#FFFFFF"
                  ScrollViewer.CanContentScroll="True" AlternationCount="2"
                  HorizontalAlignment="Stretch" VerticalAlignment="Stretch" SelectionChanged="taskDetailGrid_SelectionChanged" Grid.ColumnSpan="2" DataContextChanged="taskDetailGrid_DataContextChanged">
<DataGrid.Columns>
                    <DataGridTemplateColumn x:Name="userControlColumn" Header="Column1" IsReadOnly="True" Width="*">
                        <DataGridTemplateColumn.CellTemplate>
                            <DataTemplate>
                                <StackPanel x:Name="stkPanel">
<ListBox  x:Name="memberListBox" Margin="440,-55,0,0"  HorizontalAlignment="Left" VerticalAlignment="Top"  ItemsSource="{Binding SelectContacts}" 
                                        ItemTemplate="{StaticResource ContactInfoTemplate}" Visibility="Hidden" Width="150" PreviewMouseDown="memberListBox_PreviewMouseDown">
                                    </ListBox>
                                    <TextBox x:Name="txtComment" Text="{Binding ReportComment}" VerticalAlignment="Top" HorizontalAlignment="Right" Margin="0,-55,3,0" Width="250" Height="50"
                                             TextWrapping="Wrap" AcceptsReturn="True"/>
                                </StackPanel>
                            </DataTemplate>
                        </DataGridTemplateColumn.CellTemplate>
                    </DataGridTemplateColumn>
</DataGrid.Columns>
            </DataGrid>

var row = grid.ItemContainerGenerator.ContainerFromItem(item) as DataGridRow;

The problem is that row is always return null.

Solution can be found here. stackoverflow.com/questions/10591391/… — Slasko
I referenced this site and update as the answer 2. But row variable is yet null. — ammoe

dnvntr dnvntr · Accepted Answer · 2015-11-18T09:29:47

The default for DataGrid is to load the items with Virtualization, Which means the rows load on demand.

When the item isn't rendered, the item is NOT generated yet.

Add to your DataGrid:

EnableRowVirtualization="False"
VirtualizingStackPanel.IsVirtualizing="False"

Read more here : DataGrid.EnableRowVirtualization Property

How to Get DataGrid Rows after updating ItemsSource in wpf?

1 Answers