带有ItemTemplateSelector

Question

我有点问题。我想在我的DataGrid中有两个goupstyles。 每个组的标题都有自己的模板。选择由DataTemplateSelector确定。

问题是，当我到达选择器时，我的项目总是等于null。我希望我的绑定项（选择器中的类型是“DataReductionK”）可以返回好的模板。

谢谢！

 public class ControlGroupStyleSelector : DataTemplateSelector 
{     
    public DataTemplate StepTemplate
    { get; set; }

    public DataTemplate MotherTemplate
    { get; set; }

    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        ContentPresenter cp = container as ContentPresenter;

        if (cp != null)
        {
            CollectionViewGroup cvg = cp.Content as CollectionViewGroup;

            if (cvg != null)
            {
                if (cvg.Name.ToString().Contains("K"))
                {
                    return MotherTemplate;
                }
                else
                {
                    return StepTemplate;
                }
            }
        }

        return base.SelectTemplate(item, container);
    } 

  <DataGrid ItemsSource="{Binding DataReductionsK, Mode=OneWay}"                           AutoGenerateColumns="False"                                                     HorizontalContentAlignment="Center" >

                <DataGrid.Resources>
                    <DataTemplate x:Key="StepTemplate">
                        <Grid>
                            <StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch" Background="Transparent">
                                <Label>Passage n°</Label>
                                <Label FontWeight="Bold" FontSize="12" Content="{Binding Name}" />
                            </StackPanel>
                        </Grid>
                    </DataTemplate>
                    <DataTemplate x:Key="MotherTemplate">
                        <StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch" Background="Transparent">
                            <Label FontSize="10" Content="Control Name : " />
                            <Label FontSize="10" Content="{Binding Name}" />
                        </StackPanel>
                    </DataTemplate>

                    <selector:ControlGroupStyleSelector x:Key="ControlGroupStyleSelector" MotherTemplate="{StaticResource MotherTemplate}" StepTemplate="{StaticResource StepTemplate}" />
                </DataGrid.Resources>

                <DataGrid.Columns>

                    <DataGridTextColumn Width="85" Header="Type" Binding="{Binding ControlType}"/>
                    <DataGridTextColumn Width="120" Header="Nom du contrôle" Binding="{Binding CB_Sample}"/>
                    <DataGridTextColumn Width="85" Header="CB Dilution" Binding="{Binding CB_Dilution}"/>
                    <DataGridTextColumn Width="65" Header="Dilution" Binding="{Binding Dilution}"/>
                    <DataGridTextColumn Width="200" Header="Range d'acceptation (mlU/mL)" Binding="{Binding AcceptableRange}"/>

                    <DataGridTextColumn Width="85" Header="RLU" Binding="{Binding Step.RLU}"/>
                    <DataGridTextColumn Width="85" Header="Conc brute (mlU/mL)" Binding="{Binding Step.RawConcentration.DisplayValue}"/>
                    <DataGridTextColumn Width="85" Header="Conc calculée (mlU/mL)" Binding="{Binding Step.ComputedConcentration.DisplayValue}"/>
                    <DataGridTextColumn Width="50" Binding="{Binding Step.CV}">
                        <DataGridTextColumn.HeaderTemplate>
                            <DataTemplate>
                                <TextBlock Text="CV (%)" Width="40" TextWrapping="Wrap"/>
                            </DataTemplate>
                        </DataGridTextColumn.HeaderTemplate>
                    </DataGridTextColumn>
                    <DataGridTextColumn Width="85" Header="Final result (mlU/mL)" Binding="{Binding Step.FinalRes.DisplayValue}" FontWeight="Bold" />
                    <DataGridTextColumn Width="85" Header="Status" Binding="{Binding Step.Action}"/>

                </DataGrid.Columns>

                <DataGrid.GroupStyle>
                    <!--<GroupStyle HeaderTemplateSelector="{StaticResource ControlGroupStyleSelector}"/>-->
                    <GroupStyle>
                        <GroupStyle.ContainerStyle>
                            <Style TargetType="{x:Type GroupItem}">
                                <Setter Property="Template">
                                    <Setter.Value>
                                        <ControlTemplate TargetType="{x:Type GroupItem}">
                                            <Expander IsExpanded="True" HeaderTemplateSelector="{StaticResource ControlGroupStyleSelector}">
                                                <ItemsPresenter />
                                            </Expander>
                                        </ControlTemplate>
                                    </Setter.Value>
                                </Setter>
                            </Style>
                        </GroupStyle.ContainerStyle>
                    </GroupStyle>
                </DataGrid.GroupStyle>                   
            </DataGrid>

        </Grid>