一、问题场景
对于ItemsControl本身，默认不包含选中默认样式，内部子项默认是全填充，布局和效果如下：
<ScrollViewer VerticalScrollBarVisibility="Auto" BorderThickness="0"> <ItemsControl ItemTemplateSelector="{StaticResource ChatTemplateSelector}" x:Name="chats" Background="White" Margin="10"> <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <StackPanel></StackPanel> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> <ItemsControl.Template> <ControlTemplate TargetType="{x:Type ItemsControl}"> <Grid> <ItemsPresenter></ItemsPresenter> </Grid> </ControlTemplate> </ItemsControl.Template> </ItemsControl> </ScrollViewer>
运行效果如下：
将ItemsControl替换为ListBox或ListView出现内容无法全填充，
替换为ListBox：
<ScrollViewer VerticalScrollBarVisibility="Auto" BorderThickness="0"> <ListBox ItemTemplateSelector="{StaticResource ChatTemplateSelector}" x:Name="chats" Background="White" Margin="10"> <ListBox.ItemsPanel> <ItemsPanelTemplate> <StackPanel></StackPanel> </ItemsPanelTemplate> </ListBox.ItemsPanel> <ListBox.Template> <ControlTemplate TargetType="{x:Type ItemsControl}"> <Grid> <ItemsPresenter></ItemsPresenter> </Grid> </ControlTemplate> </ListBox.Template> </ListBox> </ScrollViewer>
替换为ListView：
<ScrollViewer VerticalScrollBarVisibility="Auto" BorderThickness="0"> <ListView ItemTemplateSelector="{StaticResource ChatTemplateSelector}" x:Name="chats" Background="White" Margin="10"> <ListView.ItemsPanel> <ItemsPanelTemplate> <StackPanel></StackPanel> </ItemsPanelTemplate> </ListView.ItemsPanel> <ListView.Template> <ControlTemplate TargetType="{x:Type ItemsControl}"> <Grid> <ItemsPresenter></ItemsPresenter> </Grid> </ControlTemplate> </ListView.Template> </ListView> </ScrollViewer>
效果如下：
二、解决方案
实际本质原因为ListBox或ListView样式中，默认配置HorizontalContentAlignment，默认为Left，直接手动添加该内容水平全填充对齐Stretch 。
修改如下：
<ScrollViewer VerticalScrollBarVisibility="Auto" BorderThickness="0"> <ListBox HorizontalContentAlignment="Stretch" ItemTemplateSelector="{StaticResource ChatTemplateSelector}" x:Name="chats" Background="White" Margin="10"> <ListBox.ItemsPanel> <ItemsPanelTemplate> <StackPanel></StackPanel> </ItemsPanelTemplate> </ListBox.ItemsPanel> <ListBox.Template> <ControlTemplate TargetType="{x:Type ItemsControl}"> <Grid> <ItemsPresenter></ItemsPresenter> </Grid> </ControlTemplate> </ListBox.Template> </ListBox> </ScrollViewer>
运行效果如下：
