XAML ScrollViewer滚动条隐藏问题（Silverlight）

Question

我遇到了这个奇怪的问题，滚动查看器中的内容尺寸增加，滚动查看器然后显示水平滚动条。然而，ScrollViewer 最终所在的网格似乎没有调整到足以显示滚动条的大小。

我已经在此示例应用程序中隔离了问题，基本上是一些 xaml 和一些后面的代码来模拟内容大小的增加。

请注意，当您单击调整大小按钮时，右侧滚动条未正确显示，我添加了一些填充以显示它在那里，但不在正确的位置。

如果我删除顶行，它似乎可以工作。

有什么想法并提前致谢各位吗？

<UserControl x:Class="SilverlightApplication7.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
mc:Ignorable="d"
>
<Grid 
    ShowGridLines="True" 
    HorizontalAlignment="Stretch" 
    VerticalAlignment="Stretch"
>
    <Grid.RowDefinitions>
        <RowDefinition x:Name="DealHeaderRow" Height="Auto" />
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition x:Name="DealBarColumn" Width="Auto"></ColumnDefinition>
        <ColumnDefinition x:Name="MarketViewerColumn" Width="Auto"></ColumnDefinition>
        <ColumnDefinition x:Name="DealEditorColumn" Width="*" ></ColumnDefinition>
        <ColumnDefinition x:Name="InfoColumn" Width="Auto"></ColumnDefinition>
    </Grid.ColumnDefinitions>

    <ContentControl 
        x:Name="DealBarRegionContentControl"
        Grid.Row="0"
        Grid.Column="0" 
        Grid.RowSpan="2"
        VerticalContentAlignment="Stretch"
        HorizontalAlignment="Stretch"
        Margin="0">
        <TextBlock Text="DealBarRegion" Width="150" />
    </ContentControl>

    <ContentControl 
        Grid.Row="0"
        Grid.Column="1" 
        Grid.RowSpan="2"
        VerticalContentAlignment="Stretch"
        HorizontalAlignment="Stretch"
        HorizontalContentAlignment="Stretch">
        <Border Background="#FF9AF172">
            <TextBlock Text="MarketViewerRegion"  Width="150"  />
        </Border>
    </ContentControl>

    <ContentControl 
        Grid.Column="2" 
        Grid.ColumnSpan="2"
        Grid.Row="0"
        HorizontalAlignment="Stretch"
        HorizontalContentAlignment="Stretch" >
        <Border Background="#FFC1FC9F">
            <TextBlock Text="DealHeaderRegion"  />
        </Border>
    </ContentControl>

    <ContentControl 
        Grid.Column="2" 
        Grid.Row="1" 
        VerticalAlignment="Top"
        HorizontalContentAlignment="Stretch" 
        VerticalContentAlignment="Stretch">
        <Border Background="MistyRose" >
            <TextBlock Text="DealEditorRegion" />
        </Border>
    </ContentControl>

    <Grid
        Grid.Column="3" 
        Grid.Row="1" 
    >
        <ContentControl 
            x:Name="InfoRegionControl" 
            VerticalContentAlignment="Stretch"
            HorizontalAlignment="Stretch">
            <!-- without the padding here you can't see the scroll bar at all !! Its like the 
            scroll ScrollViewer isn't correctly calculating its width to include the scroll bar,
            or the grid isn't sizing at the points its visible??-->
            <Border Padding="0,0,9,0" MinWidth="200" x:Name="DealInfoControlPlaceHolder">
                <ScrollViewer  
                    HorizontalAlignment="Stretch" 
                    HorizontalContentAlignment="Stretch"
                    VerticalScrollBarVisibility="Auto" 
                    HorizontalScrollBarVisibility="Auto"  
                    >
                    <StackPanel x:Name="ScrollContentPlaceHolder">
                        <Button Click="Button_Click" Content="Rezize Column" x:Name="ResizeButton" />
                    </StackPanel>
                </ScrollViewer>
            </Border>
        </ContentControl>
    </Grid>
</Grid>

这是背后的代码：

using System.Windows;
using System.Windows.Controls;

namespace SilverlightApplication7
{
    public partial class MainPage : UserControl
    {
        double _dealInfoControlPlaceHolderHeight = 0;
        double _dealInfoControlPlaceHolderWidth = 0;

        public MainPage()
        {
            InitializeComponent();

            Loaded += (o, e) =>
            {
                // cache the original width and height
                _dealInfoControlPlaceHolderHeight = DealInfoControlPlaceHolder.Height;
                _dealInfoControlPlaceHolderWidth = DealInfoControlPlaceHolder.Width;
            };
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            if (ScrollContentPlaceHolder.Height == 1200)
            {
                ScrollContentPlaceHolder.Height = _dealInfoControlPlaceHolderHeight;
                ScrollContentPlaceHolder.Width = _dealInfoControlPlaceHolderWidth;
            }
            else
            {
                ScrollContentPlaceHolder.Height = 1200;
                ScrollContentPlaceHolder.Width = 250;
            }
        }
    }
}

Answer 1

好吧，我不知道为什么上面的方法不起作用，但作为一种解决方法，我只是重组页面，使其行为相同。有效：

<UserControl x:Class="SilverlightApplication7.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
mc:Ignorable="d"
>
<Grid 
    ShowGridLines="True" 
    HorizontalAlignment="Stretch" 
    VerticalAlignment="Stretch"
>
    <Grid.RowDefinitions>
        <RowDefinition Height="*" />
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition x:Name="DealBarColumn" Width="Auto"></ColumnDefinition>
        <ColumnDefinition x:Name="MarketViewerColumn" Width="Auto"></ColumnDefinition>
        <ColumnDefinition x:Name="DealEditorColumn" Width="*" ></ColumnDefinition>
    </Grid.ColumnDefinitions>

    <ContentControl 
        x:Name="DealBarRegionContentControl"
        Grid.Column="0" 
        VerticalContentAlignment="Stretch"
        HorizontalAlignment="Stretch"
        Margin="0">
        <TextBlock Text="DealBarRegion" Width="150" />
    </ContentControl>

    <ContentControl 
        Grid.Column="1" 
        VerticalContentAlignment="Stretch"
        HorizontalAlignment="Stretch"
        HorizontalContentAlignment="Stretch">
        <Border Background="#FF9AF172">
            <TextBlock Text="MarketViewerRegion"  Width="150"  />
        </Border>
    </ContentControl>

    <Grid
        Grid.Column="2" >
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>

        <ContentControl 
            Grid.Row="0"
            HorizontalAlignment="Stretch"
            HorizontalContentAlignment="Stretch" >
            <Border Background="#FFC1FC9F">
                <TextBlock Text="DealHeaderRegion"  />
            </Border>
        </ContentControl>

        <Grid 
            Grid.Row="1"     
            HorizontalAlignment="Stretch"
            VerticalAlignment="Stretch"
            >
            <Grid.ColumnDefinitions>
                <ColumnDefinition Width="*"></ColumnDefinition>
                <ColumnDefinition Width="Auto"></ColumnDefinition>
            </Grid.ColumnDefinitions>
            <ContentControl 
                Grid.Column="0"
                VerticalAlignment="Top"
                HorizontalContentAlignment="Stretch" 
                VerticalContentAlignment="Stretch">
                <Border Background="MistyRose" >
                    <TextBlock Text="DealEditorRegion" />
                </Border>
            </ContentControl>
            <ContentControl 
                Grid.Column="1"
                x:Name="InfoRegionControl" 
                VerticalContentAlignment="Stretch"
                HorizontalAlignment="Right">
                <!-- without the padding here you can't see the scroll bar at all !! Its like the 
                scroll ScrollViewer isn't correctly calculating its width to include the scroll bar,
                or the grid isn't sizing at the points its visible??-->
                <Border Padding="0,0,9,0" MinWidth="200" x:Name="DealInfoControlPlaceHolder">
                    <ScrollViewer  
                        HorizontalAlignment="Stretch" 
                        HorizontalContentAlignment="Stretch"
                        VerticalScrollBarVisibility="Auto" 
                        HorizontalScrollBarVisibility="Auto"  
                        >
                        <StackPanel x:Name="ScrollContentPlaceHolder">
                            <Button Click="Button_Click" Content="Rezize Column" x:Name="ResizeButton" />
                        </StackPanel>
                    </ScrollViewer>
                </Border>
            </ContentControl>
        </Grid>
    </Grid>
</Grid>