Question

I have a WPF application in which I use entity framework with mysql connector/net to obtain data back. I have a combobox which is filled with items from a table. A datagrids itemssource property is binded to the combobox’ selecteditem.staff property, which displays the data correctly. The problem is that I am unable to sort this data. If I bind the data directly to the datagrid, the sorting works correctly. However if I bind the data to the combobox, then bind the datagrid to the selected item of the grid, the sorting is lost.

Entity Framework Data Retrieval

    private void RefreshOffices()
    {
        try
        {
            using (var context = new LDC_Entities())
            {
                cmbOffice.ItemsSource = context.Offices.Include("Staff.Roles").Include("Manager").ToList();
            }
        }
        catch (Exception eX)
        {
            MessageBox.Show(String.Format("Unable to retrieve offices\nError:{0}", eX.Message),"Error",
                MessageBoxButton.OK, MessageBoxImage.Error);
        }
    }

XAML Binding

<ComboBox Name="cmbOffice" Width="150" SelectedIndex="0">
<ComboBox.ItemTemplate>
    <DataTemplate>
        <TextBlock>
            <TextBlock.Text>
              <MultiBinding StringFormat="{}({0}) - {1}">
                <Binding Path="Office_ID"/>
                <Binding Path="City"/>
              </MultiBinding>
            </TextBlock.Text>
        </TextBlock>
    </DataTemplate>
</ComboBox.ItemTemplate>
</ComboBox>

<DataGrid Grid.Row="1" Margin="10,50,10,10" Name="displayGrid" IsReadOnly="True" AutoGenerateColumns="False" 
      ItemsSource="{Binding ElementName=cmbOffice, Path=SelectedItem.Staff}">
<DataGrid.Columns>
    <DataGridTextColumn Header="Staff ID" Binding="{Binding Staff_ID}"/>
    <DataGridTextColumn Header="Name" Width="120" Binding="{Binding Full_Name}" />
    <DataGridTextColumn Header="Address" Width="140" Binding="{Binding Address}" />
    <DataGridTextColumn Header="DOB" Width="80" Binding="{Binding DOB, StringFormat={}{0:dd/MM/yyyy}}" />
    <DataGridTextColumn Header="Telephone" Width="100" Binding="{Binding Telephone}" />
    <DataGridTextColumn Header="Roles" Width="*" Binding="{Binding RolesList}" />
</DataGrid.Columns>
</DataGrid>

Any help would be much appreciated, I have tried playing with the CanUserSort property of the datagrid to no success. I believe it is to do with how the datagrid is filled not by the selected item, but by the .staff collection of staff members.

Thanks in advance,
Mike

Answer 1

First I would try to specify binding direction with Mode for DataGrid, like this

<DataGrid Grid.Row="1" Margin="10,50,10,10" Name="displayGrid" IsReadOnly="True" AutoGenerateColumns="False" 
      ItemsSource="{Binding ElementName=cmbOffice, Path=SelectedItem.Staff, Mode=OneWay}">
<DataGrid.Columns>

if this doesn’t work for you, another solution could be:

First bind SelectedItem of the combo to a property, DataGrid bind to another collection.
On combo binded change, populate DataGrid‘s binded collection with sorted data.

Hope this helps.