WPF ScrollViewer：水平滾動不起作用

Question

爲什麼不支持水平滾動？

<ScrollViewer> 
    <ItemsControl ItemsSource="{Binding Territories}" HorizontalAlignment="Left"> 
     <ItemsControl.ItemsPanel> 
      <ItemsPanelTemplate> 
       <VirtualizingStackPanel CanHorizontallyScroll="True" ScrollViewer.HorizontalScrollBarVisibility="Visible" ScrollViewer.VerticalScrollBarVisibility="Auto" > 

       </VirtualizingStackPanel> 
      </ItemsPanelTemplate> 
     </ItemsControl.ItemsPanel> 
     <ItemsControl.ItemTemplate> 
      <DataTemplate> 
       <Grid > 
        <Grid.RowDefinitions> 
         <RowDefinition Height="Auto"/> 
         <RowDefinition Height="Auto"/> 
        </Grid.RowDefinitions> 
        <Grid.ColumnDefinitions> 
         <ColumnDefinition Width="75" /> 
         <ColumnDefinition Width="75" /> 
         <ColumnDefinition Width="150" /> 
         <ColumnDefinition Width="150" /> 
         <ColumnDefinition Width="65" /> 
         <ColumnDefinition Width="60" /> 
         <ColumnDefinition Width="75" /> 
         <ColumnDefinition Width="75" /> 
        </Grid.ColumnDefinitions> 

        <TextBox Grid.Row="0" Grid.Column="0" Text="{Binding Quantity, StringFormat=N0, ValidatesOnDataErrors=True}" /> 
        <TextBox Grid.Row="0" Grid.Column="1" Text="{Binding ProductionNumber, ValidatesOnDataErrors=True}" /> 

        <ComboBox Grid.Row="0" Grid.Column="2" SelectedValuePath="PrimaryKey" SelectedValue="{Binding RepKey}" ItemsSource="{Binding RepCanidates}" TextSearch.TextPath="FullName" Margin="4"> 
         <ComboBox.ItemTemplate> 
          <DataTemplate> 
           <TextBlock Text="{Binding FullName}" ToolTip="{Binding FullName}" Width="150" /> 
          </DataTemplate> 
         </ComboBox.ItemTemplate> 

         <ComboBox.ItemContainerStyle> 
          <Style TargetType="{x:Type ComboBoxItem}"> 
           <Setter Property="Template"> 
            <Setter.Value> 
             <ControlTemplate TargetType="{x:Type ComboBoxItem}"> 
              <Border x:Name="Bd" 
                   BorderBrush="{TemplateBinding BorderBrush}" 
                   BorderThickness="{TemplateBinding BorderThickness}" 
                   Background="{TemplateBinding Background}"> 
               <StackPanel Orientation="Horizontal"> 
                <ContentPresenter HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
               VerticalAlignment="{TemplateBinding VerticalContentAlignment}" /> 
                <TextBlock Text="{Binding CompanyBranchName}" ToolTip="{Binding CompanyBranchName}" Width="200"/> 
                <TextBlock Margin="4,0,0,0" Text="{Binding ShortAddress}" ToolTip="{Binding ShortAddress}" /> 
               </StackPanel> 
              </Border> 
              <ControlTemplate.Triggers> 
               <Trigger Property="IsHighlighted" Value="True"> 
                <Setter TargetName="Bd" Property="Background" Value="{DynamicResource {x:Static SystemColors.HighlightBrushKey}}" /> 
                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.HighlightTextBrushKey}}" /> 
               </Trigger> 
               <Trigger Property="IsEnabled" Value="False"> 
                <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.GrayTextBrushKey}}" /> 
               </Trigger> 
              </ControlTemplate.Triggers> 
             </ControlTemplate> 
            </Setter.Value> 
           </Setter> 
          </Style> 
         </ComboBox.ItemContainerStyle> 

        </ComboBox> 

        <Button Grid.Row="1" Grid.Column="2" Content="Advanced Search" Name="cmdAdvancedSearch" Click="cmdAdvancedSearch_Click" /> 

        <ComboBox Grid.Row="0" Grid.Column="3" SelectedValuePath="PrimaryKey" SelectedValue="{Binding CompanyBranchKey}" ItemsSource="{Binding CompanyBranchCanidates}" Margin="4" IsEnabled="{Binding CompanyBranchKeyEditable}"> 

        </ComboBox> 

        <TextBox Grid.Row="0" Grid.Column="4" Text="{Binding ZipCode}" IsEnabled="{Binding ZipCodeEditable}"/> 

        <ComboBox Grid.Row="0" Grid.Column="5" SelectedValuePath="PrimaryKey" SelectedValue="{Binding StateKey}" ItemsSource="{Binding StateCanidates}" Margin="4" IsEnabled="{Binding StateKeyEditable}"> 
         <ComboBox.ItemTemplate> 
          <DataTemplate> 
           <TextBlock Text="{Binding State}" ToolTip="{Binding StateName}" /> 
          </DataTemplate> 
         </ComboBox.ItemTemplate> 

        </ComboBox> 

        <ComboBox Grid.Row="0" Grid.Column="6" SelectedValuePath="PrimaryKey" SelectedValue="{Binding TerritoryKey, ValidatesOnDataErrors=True}" ItemsSource="{Binding TerritoryCanidates}" Margin="4" IsEnabled="{Binding TerritoryKeyEditable}"> 

        </ComboBox> 

        <Button Grid.Row="0" Grid.Column="7" Content="Delete" Click="cmdDeleteRow_Click" Margin="4" /> 

       </Grid> 
      </DataTemplate> 
     </ItemsControl.ItemTemplate> 
    </ItemsControl> 
</ScrollViewer> 

Answer 1

這種變化將工作：

<ScrollViewer ScrollViewer.HorizontalScrollBarVisibility="Auto" ScrollViewer.VerticalScrollBarVisibility="Visible">