WPF网格没有显示滚动条

Question

在.NET 3.5中,我在窗口中有一个网格.我用Buttons填充这个Grid.当按钮填满网格并离开视图时,网格不显示滚动条.我已将网格垂直滚动设置为可见但仍未显示.

<Window x:Name="Window" x:Class="MergeToCheck.CheckList"
             xmlns:sys="clr-namespace:System;assembly=mscorlib"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
             mc:Ignorable="d" Loaded="Window_Loaded" ScrollViewer.VerticalScrollBarVisibility="Disabled"
                ResizeMode="NoResize" ShowInTaskbar="False" Topmost="True" WindowStyle="None" 
        Height="671" Width="846.299" BorderThickness="5">

    <Grid>
        <Grid x:Name="MyGrid" HorizontalAlignment="Left" Height="535" VerticalAlignment="Top" Width="736" Margin="10,63,0,0" ScrollViewer.CanContentScroll="True" ScrollViewer.HorizontalScrollBarVisibility="Visible">
            <Grid.Resources>
                <Style TargetType="{x:Type Panel}">
                    <Setter Property="Margin" Value="0,0,0,6" />
                </Style>
            </Grid.Resources>
            <Grid.ColumnDefinitions>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
                <ColumnDefinition/>
            </Grid.ColumnDefinitions>
        </Grid>        
    </Grid>
</Window>

添加按钮的代码:

        CheckList CheckListCtrl = new CheckList();

        System.Windows.Controls.Button btn;
        int row = 0;
        int col = 0;

        CheckListCtrl.MyGrid.RowDefinitions.Add(new RowDefinition() { Height = new GridLength(100) });

        foreach(var c in list)
        {
            btn = new System.Windows.Controls.Button();
            btn.FontSize = 15;
            btn.FontWeight = FontWeights.UltraBold;
            btn.Content = c.Name;
            btn.Style = System.Windows.Application.Current.FindResource(System.Windows.Controls.ToolBar.ButtonStyleKey) as Style;
            btn.BorderBrush = new SolidColorBrush(Colors.Black);
            btn.BorderThickness = new Thickness(2);
            btn.MinWidth = 145;
            btn.MaxWidth = 145;
            btn.MinHeight = 95;
            btn.MaxHeight = 95;

            btn.SetValue(Grid.RowProperty, row);
            btn.SetValue(Grid.ColumnProperty, col);

            CheckListCtrl.MyGrid.Children.Add(btn);

            if ((col + 1) % CheckListCtrl.MyGrid.ColumnDefinitions.Count == 0)
            {                    
                col = 0;
                row++;
                CheckListCtrl.MyGrid.RowDefinitions.Add(new RowDefinition() { Height = new GridLength(100) });
            }
            else
                col++;
        }

Answer 1

Grid不支持滚动功能.如果你想滚动你需要ScrollViewer控制的东西

<ScrollViewer HorizontalScrollBarVisibility="Visible">
   <Grid x:Name="MyGrid" HorizontalAlignment="Left" Height="535" VerticalAlignment="Top" Width="736" Margin="10,63,0,0">
      <Grid.Resources>
         <Style TargetType="{x:Type Panel}">
            <Setter Property="Margin" Value="0,0,0,6" />
         </Style>
      </Grid.Resources>
      <Grid.ColumnDefinitions>
         <ColumnDefinition/>
         <ColumnDefinition/>
         <ColumnDefinition/>
         <ColumnDefinition/>
         <ColumnDefinition/>
      </Grid.ColumnDefinitions>
   </Grid>        
</ScrollViewer>

Answer 2

一般来说，需要告诉 ScrollViewer 它小于其内容。因此，仅添加 ScrollViewer 以使控件可滚动并不总是足够的。ScrollViewer 知道，如果其封闭控件具有固定或最大尺寸，或者其本身具有固定高度或最大高度，则它会较小，如下所示

<ScrollViewer Height=500 HorizontalScrollBarVisibility="Visible">
...
</ScrollViewer>

，或者它的 Height （或 MaxHeight）是否绑定到适当的东西。

水平滚动条也是如此，您可以将其设置为可见，如果 ScrollViewer 的宽度不受限制，ScrollViewer 将扩展到其内容的大小。如果滚动条可见性为“自动”，则不会显示滚动条；如果为“可见”，则将显示禁用的滚动条。（请注意，Horizo​​ntalScrollbarVisibility 默认情况下为“禁用”。）要获得有用的水平滚动条，请限制 ScrollViewer 的宽度并将其 ​​Horizo​​ntalScrollbarVisibility 设置为至少“自动”。