WPF Data Binding ComboBox in DataGridTemplateColumn

I have a DataGrid and I want to populate a column that contains a ComboBox with a dynamic ItemsSource of elements, based on the row. I have the combo box display correctly, and the correct list of elements are populated in the list, as pulled in from the AvailableLogFileProcessTypes property, which is a ReadOnlyCollection. However, when the selection is made by the user in the combobox, the LogFileProcessType property is not set 开发者_StackOverflow社区to the selection.

Data:

Property LogFileDirectories, IEnumerable<LogFileData>,
LogFileData:
public LogFileProcessType LogFileProcessType{get;set;}
public ReadOnlyCollection<LogFileProcessType> AvailableLogFileProcessTypes { get; set; }

The property currently has a backing field, and the breakpoint in the set property does not get hit, so I know it is localized to the binding setup. What is wrong with my XAML that is preventing the property from being set?

As you can see, I've tried setting both the SelectedValue and SelectedItem in the CellEditingTemplate and the CellTemplate. I am not sure which of these is appropriate.

 <DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Path=LogFileDirectories, UpdateSourceTrigger=PropertyChanged}"
      HeadersVisibility="Column" CanUserReorderColumns="False" CanUserAddRows="False" Margin="0,0,0,35" Grid.RowSpan="3">
<DataGrid.Columns>
    <DataGridCheckBoxColumn Header="Processed" Binding="{Binding Path=IsProcessingComplete, Mode=OneWay}" Width="70" IsReadOnly="True" />
    <DataGridTemplateColumn Header="template">
        <DataGridTemplateColumn.CellEditingTemplate>
            <DataTemplate>
                <ComboBox SelectedValue="{Binding Path=LogFileProcessType, Mode=TwoWay}"
                          SelectedItem="{Binding Path=LogFileProcessType, Mode=TwoWay}"
                          ItemsSource="{Binding Path=AvailableLogFileProcessTypes}"/>
            </DataTemplate>
        </DataGridTemplateColumn.CellEditingTemplate>      
        <DataGridTemplateColumn.CellTemplate>
            <DataTemplate>
                <ComboBox SelectedValue="{Binding Path=LogFileProcessType, Mode=TwoWay}"
                          SelectedItem="{Binding Path=LogFileProcessType, Mode=TwoWay}"
                          ItemsSource="{Binding Path=AvailableLogFileProcessTypes}"/>
            </DataTemplate>
        </DataGridTemplateColumn.CellTemplate>                            
    </DataGridTemplateColumn>                        
</DataGrid.Columns>                    
</DataGrid>

See Damascus response for thought process.

Need to Specify UpdateSourceTrigger on CellTemplate / CelLEditTemplate. This triggers the property change.

 <DataGridTemplateColumn Header="template">
    <DataGridTemplateColumn.CellEditingTemplate>
        <DataTemplate>
            <ComboBox SelectedValue="{Binding Path=LogFileProcessType, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                      ItemsSource="{Binding Path=AvailableLogFileProcessTypes}"/>
        </DataTemplate>
    </DataGridTemplateColumn.CellEditingTemplate>      
    <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <ComboBox SelectedValue="{Binding Path=LogFileProcessType, UpdateSourceTrigger=PropertyChanged}"
                      ItemsSource="{Binding Path=AvailableLogFileProcessTypes}"/>
        </DataTemplate>
    </DataGridTemplateColumn.CellTemplate>                            
</DataGridTemplateColumn>  

Try to add this to your ComboBox :

<ComboBox SelectedValue="{Binding Path=LogFileProcessType, Mode=TwoWay}"
                          SelectedItem="{Binding Path=LogFileProcessType, Mode=TwoWay}"
                          ItemsSource="{Binding Path=AvailableLogFileProcessTypes, UpdateSourceTrigger=PropertyChanged}"/>

Therefore, with an UpdateSourceTrigger set to PropertyChanged, each time the object AvailableLogFileProcessTypes will change and call OnPropertyChanged, the ItemsSource will be refreshed.