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Night Walker
Night Walker

Reputation: 21280

DataGridComboBoxColumn data binding

I am trying to databind DataGridComboBoxColumn

<DataGridComboBoxColumn Header="Number of Copies" SelectedItemBinding="{Binding NumberCopies}">
    <DataGridComboBoxColumn.ElementStyle>
       <Style TargetType="ComboBox">
          <Setter Property="ItemsSource" Value="{Binding LifeAreaList}"/>
          <Setter Property="IsReadOnly" Value="True"/>
       </Style>
    </DataGridComboBoxColumn.ElementStyle>
</DataGridComboBoxColumn>

What I am doing wrong here , because I am getting an empty combobox in the run time .

I got following

System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=LifeAreaList; DataItem=null; target element is 'DataGridComboBoxColumn' (HashCode=49475561); target property is 'ItemsSource' (type 'IEnumerable')

Upvotes: 7

Views: 4524

Answers (5)

Snail
Snail

Reputation: 109

If you would to use something similar to DataGridCobmoboxColumn may it be better to use the DataGridTemplateColumn you can use it and have the same functionality without need to use for ItemsSource StaticResource.

I set the root element in RelativeSource as UserControl, if your DataGrid is located inside a Window or Page, you will need to use them accordingly.

<DataGridTemplateColumn Header="Number of Copies">
          <DataGridTemplateColumn.CellTemplate>
              <DataTemplate>
                  <TextBlock Text="{Binding NumberCopies}"/>
              </DataTemplate>
          </DataGridTemplateColumn.CellTemplate>
          <DataGridTemplateColumn.CellEditingTemplate>
              <DataTemplate>
                  <ComboBox SelectedItem="{Binding NumberCopies, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
ItemsSource="{Binding DataContext.LifeAreaList, RelativeSource={RelativeSource FindAncestor, AncestorType=UserControl}}"/>
                  </DataTemplate>
              </DataGridTemplateColumn.CellEditingTemplate>
          </DataGridTemplateColumn>

Upvotes: 0

Fredrik Hedblad
Fredrik Hedblad

Reputation: 84684

DataGridColumn doesn't derive from FrameworkElement or FrameworkContentElement so it isn't in the visual tree and doens't have a DataContext and that's why your Binding is failing.

If the List<int> that you're binding to is the same for every item then maybe you should find another way to bind to it, maybe you could make it static and use StaticResource in the Binding.

Anyway, to bind ItemsSource to a List<int> property in your source class you can use ElementStyle and ElementEditingStyle (as pointed out by others). The following should work

<DataGridComboBoxColumn Header="Number of Copies"
                        SelectedItemBinding="{Binding ListAreaItem}">
    <DataGridComboBoxColumn.ElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding LifeAreaList}"/>
        </Style>
    </DataGridComboBoxColumn.ElementStyle>
    <DataGridComboBoxColumn.EditingElementStyle>
        <Style TargetType="ComboBox">
            <Setter Property="ItemsSource" Value="{Binding LifeAreaList}"/>
        </Style>
    </DataGridComboBoxColumn.EditingElementStyle>
</DataGridComboBoxColumn>

Upvotes: 9

brunnerh
brunnerh

Reputation: 185553

You are not supposed to set the ItemsSource in the style, the column itself has such a property which may override anything you may try to set in the style. Further, you try to set it in the wrong style (that style is for the display mode), you could try setting it in the EditingElementStyle instead, but i would not recommend that either.

Upvotes: 2

paparazzo
paparazzo

Reputation: 45106

I would try a regular DataGridColumn with PresentationTraceSources.TraceLevel="High" and see if you are are having a binding problem.

Upvotes: 0

RockWorld
RockWorld

Reputation: 1288

Why are you setting Items source in style?

Can you try this code:

 <my:DataGridTemplateColumn Header="Number of Copies" >
                    <my:DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <ComboBox ItemsSource="{Binding Path=LifeAreaList}"  >
                               <ComboBox.ItemTemplate>
                                <DataTemplate>
                                    <Label Content="{Binding .}"></Label>
                                </DataTemplate>
                               </ComboBox.ItemTemplate>
                            </ComboBox>
                        </DataTemplate>
                    </my:DataGridTemplateColumn.CellTemplate>
                </my:DataGridTemplateColumn>

Define Data template for DataGridTemplateColumn if LifeAreaList is complex class collection and you want to display it in customized way.

Upvotes: 1

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