WPF ItemsControl 取消选中item项，滚动条自动跑到该item顶部的问题

Posted 2020-08-05

项目中ItemsControl 自定义了DataTemplate，代码如下：

<ScrollViewer x:Name="PaperScrollCiewer"  Margin="1" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto" Background="#ccc" ScrollChanged="PaperScrollCiewer_ScrollChanged" >
            <ItemsControl x:Name="MainItemsControl">
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <StackPanel/>
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="10"></RowDefinition>
                                <RowDefinition Height="10*"></RowDefinition>
                            </Grid.RowDefinitions>
                            <InkCanvas Grid.Row="1" Background="{Binding ImgPath,Converter={StaticResource BitmapSourceConvert}}" Strokes="{Binding Strokes}" Width="{Binding Width}" Height="{Binding Height}">
                                <InkCanvas.DefaultDrawingAttributes>
                                    <DrawingAttributes Color="#FFFB1818" FitToCurve="False" Height="3" IgnorePressure="False" IsHighlighter="False" StylusTip="Ellipse" StylusTipTransform="Identity" Width="3"/>
                                </InkCanvas.DefaultDrawingAttributes>
                            </InkCanvas>
                        </Grid>
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
            </ItemsControl>
        </ScrollViewer>

　　其中InkCanvas是用来添加墨迹的，功能就是想实现加载很多个画布，每个画布能单独的绘制墨迹。运行时候发现第一次点击某一个画布，滚动条就自动调整到该item的顶部去了，猜想是触发了SelectedChange事件，默认该item选中时候需要对齐。

　　解决方法很简单，给ItemsControl设置属性CanContentScroll="True"，完美解决。

　　修改后代码如下：

<ScrollViewer x:Name="PaperScrollCiewer"  Margin="1" HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto" Background="#ccc" ScrollChanged="PaperScrollCiewer_ScrollChanged" CanContentScroll="True">
            <ItemsControl x:Name="MainItemsControl">
                <ItemsControl.ItemsPanel>
                    <ItemsPanelTemplate>
                        <StackPanel/>
                    </ItemsPanelTemplate>
                </ItemsControl.ItemsPanel>
                <ItemsControl.ItemTemplate>
                    <DataTemplate>
                        <Grid>
                            <Grid.RowDefinitions>
                                <RowDefinition Height="10"></RowDefinition>
                                <RowDefinition Height="10*"></RowDefinition>
                            </Grid.RowDefinitions>
                            <InkCanvas Grid.Row="1" Background="{Binding ImgPath,Converter={StaticResource BitmapSourceConvert}}" Strokes="{Binding Strokes}" Width="{Binding Width}" Height="{Binding Height}">
                                <InkCanvas.DefaultDrawingAttributes>
                                    <DrawingAttributes Color="#FFFB1818" FitToCurve="False" Height="3" IgnorePressure="False" IsHighlighter="False" StylusTip="Ellipse" StylusTipTransform="Identity" Width="3"/>
                                </InkCanvas.DefaultDrawingAttributes>
                            </InkCanvas>
                        </Grid>
                    </DataTemplate>
                </ItemsControl.ItemTemplate>
            </ItemsControl>
        </ScrollViewer>