DataGridはItemsControlであり、ItemsControlのContentPropertyはItemsプロパティです。逆コンパイルされたソースは次のとおりです。ContentProperty属性に注意してください。
[DefaultEvent("OnItemsChanged"), DefaultProperty("Items")]
[ContentProperty("Items")]
[StyleTypedProperty(Property = "ItemContainerStyle", StyleTargetType = typeof(FrameworkElement))]
[Localizability(LocalizationCategory.None, Readability = Readability.Unreadable)] // cannot be read & localized as string
public class ItemsControl : Control, IAddChild, IGeneratorHost
{
これは、次のようなことを行う場合、次のことを意味します。
<DataGrid>
<SomethingHere>
</DataGrid>
次に<SomethingHere>
、コンテンツである-がItems
プロパティに適用されます。その後、ItemsSource
プロパティにバインドすると、「ItemsSourceを使用する前にItemsコレクションを空にする必要があります」というエラーが表示されます。
使用した場合
<DataGrid>
<DataGrid.Template>
<ControlTemplate> ...
エラーは発生しません。
いずれの場合も、BlendまたはVS11を使用してDataGridの完全なControlTemplateを抽出し、それを変更することをお勧めします。
<Style x:Key="{ComponentResourceKey ResourceId=DataGridSelectAllButtonStyle, TypeInTargetAssembly={x:Type DataGrid}}" TargetType="{x:Type Button}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type Button}">
<Grid>
<Rectangle x:Name="Border" Fill="{DynamicResource {x:Static SystemColors.ControlBrushKey}}" SnapsToDevicePixels="True"/>
<Polygon x:Name="Arrow" Fill="Black" HorizontalAlignment="Right" Margin="8,8,3,3" Opacity="0.15" Points="0,10 10,10 10,0" Stretch="Uniform" VerticalAlignment="Bottom"/>
</Grid>
<ControlTemplate.Triggers>
<Trigger Property="IsMouseOver" Value="True">
<Setter Property="Stroke" TargetName="Border" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}"/>
</Trigger>
<Trigger Property="IsPressed" Value="True">
<Setter Property="Fill" TargetName="Border" Value="{DynamicResource {x:Static SystemColors.ControlDarkBrushKey}}"/>
</Trigger>
<Trigger Property="IsEnabled" Value="False">
<Setter Property="Visibility" TargetName="Arrow" Value="Collapsed"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<Style x:Key="DataGridStyle1" TargetType="{x:Type DataGrid}">
<Setter Property="Background" Value="{DynamicResource {x:Static SystemColors.ControlBrushKey}}"/>
<Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
<Setter Property="BorderBrush" Value="#FF688CAF"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="RowDetailsVisibilityMode" Value="VisibleWhenSelected"/>
<Setter Property="ScrollViewer.CanContentScroll" Value="true"/>
<Setter Property="ScrollViewer.PanningMode" Value="Both"/>
<Setter Property="Stylus.IsFlicksEnabled" Value="False"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type DataGrid}">
<Border BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="True">
<ScrollViewer x:Name="DG_ScrollViewer" Focusable="false">
<ScrollViewer.Template>
<ControlTemplate TargetType="{x:Type ScrollViewer}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="Auto"/>
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Button Command="{x:Static DataGrid.SelectAllCommand}" Focusable="false" Style="{DynamicResource {ComponentResourceKey ResourceId=DataGridSelectAllButtonStyle, TypeInTargetAssembly={x:Type DataGrid}}}" Visibility="{Binding HeadersVisibility, ConverterParameter={x:Static DataGridHeadersVisibility.All}, Converter={x:Static DataGrid.HeadersVisibilityConverter}, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}" Width="{Binding CellsPanelHorizontalOffset, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"/>
<DataGridColumnHeadersPresenter x:Name="PART_ColumnHeadersPresenter" Grid.Column="1" Visibility="{Binding HeadersVisibility, ConverterParameter={x:Static DataGridHeadersVisibility.Column}, Converter={x:Static DataGrid.HeadersVisibilityConverter}, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"/>
<ScrollContentPresenter x:Name="PART_ScrollContentPresenter" CanContentScroll="{TemplateBinding CanContentScroll}" Grid.ColumnSpan="2" Grid.Row="1"/>
<ScrollBar x:Name="PART_VerticalScrollBar" Grid.Column="2" Maximum="{TemplateBinding ScrollableHeight}" Orientation="Vertical" Grid.Row="1" Visibility="{TemplateBinding ComputedVerticalScrollBarVisibility}" Value="{Binding VerticalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportHeight}"/>
<Grid Grid.Column="1" Grid.Row="2">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="{Binding NonFrozenColumnsViewportHorizontalOffset, RelativeSource={RelativeSource AncestorType={x:Type DataGrid}}}"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<ScrollBar x:Name="PART_HorizontalScrollBar" Grid.Column="1" Maximum="{TemplateBinding ScrollableWidth}" Orientation="Horizontal" Visibility="{TemplateBinding ComputedHorizontalScrollBarVisibility}" Value="{Binding HorizontalOffset, Mode=OneWay, RelativeSource={RelativeSource TemplatedParent}}" ViewportSize="{TemplateBinding ViewportWidth}"/>
</Grid>
</Grid>
</ControlTemplate>
</ScrollViewer.Template>
<Grid>
<ItemsPresenter SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}"/>
<!-- your canvas here -->
<Canvas Width="128" VerticalAlignment="Stretch" HorizontalAlignment="Left" Grid.Row="0" Margin="0,25,0,0">
<Rectangle Width="32" Height="256" Canvas.Top="0" Canvas.Left="0" Stroke="Black" StrokeThickness="2" />
</Canvas>
</Grid>
</ScrollViewer>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="IsGrouping" Value="true">
<Setter Property="ScrollViewer.CanContentScroll" Value="false"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<Grid>
<DataGrid HorizontalAlignment="Left" Margin="125,110,0,0" VerticalAlignment="Top" Height="134" Width="258" Style="{DynamicResource DataGridStyle1}"/>
</Grid>