WPF:崩溃GridSplitter？

Question

我有一个WPF页面,上面有一个Grid.

有三排.第0行包含GridView Height="*".第1行包含GridSplitter Height="auto".第2行包含详细信息表单Height="2*".

这是事情 - 我有一个按钮,应该切换详细信息表单的可见性.这很好用.除了它只隐藏第2行中的表单,它不会扩展第0行中的网格以填充空格.我想要的是按钮在第0行中切换GridView以占用所有空间,然后切换回原来的位置.

显然,使用行内表单的可见性无法完成我想要的任务.

但是我需要玩什么呢？

Answer 1

我们假设我有这个XAML布局:

  <Grid Name="MyGrid">
      <Grid.RowDefinitions>
          <RowDefinition />
          <RowDefinition Height="Auto" />
          <RowDefinition />
      </Grid.RowDefinitions>
      <MyControl1 ... Grid.Row="0" />
      <GridSplitter Grid.Row="1" VerticalAlignment="Center" HorizontalAlignment="Stretch" ShowsPreview="True" Height="5" />
      <MyControl2 ... Grid.Row="2" />
  </Grid>

然后我可以使用此代码隐藏第二个控件(折叠拆分器)(相当于Height="0"在XAML 中设置):

  MyGrid.RowDefinitions[2].Height = new GridLength(0);

并使用此代码解开它(相当于Height="1*"在XAML 中设置,这是RowDefinition的默认设置):

  MyGrid.RowDefinitions[2].Height = new GridLength(1, GridUnitType.Star);

这是拆分器在用户移动时所覆盖的内容.

Answer 2

如果有人想要一个纯粹的XAML解决方案，我可以想到一种使用样式，设置器和触发器来隐藏分隔符和相关行的方法。

我用一个静态的资源为我的风格，这是设置为改变Height和MaxHeight特定的约束布尔设置时。

<Style x:Key="showRow" TargetType="{x:Type RowDefinition}">
  <Style.Setters>
    <Setter Property="Height" Value="*"/>
  </Style.Setters>
  <Style.Triggers>
    <DataTrigger Binding="{Binding MyShowRowBool}" Value="False">
      <DataTrigger.Setters>
        <Setter Property="Height" Value="0"/>
        <Setter Property="MaxHeight" Value="0"/>
      </DataTrigger.Setters>
    </DataTrigger>
  </Style.Triggers>
</Style>

我只是将样式应用于相关的行定义，它的工作就像一个魅力：

<Grid.RowDefinitions>
  <RowDefinition Height="*"/>
  <RowDefinition Style="{StaticResource showRow}"/>
  <RowDefinition Style="{StaticResource showRow}"/>
</Grid.RowDefinitions>

值得注意的是，我在没有MaxHeight属性的情况下进行了尝试，并且无法正常折叠。添加它似乎为我完成了窍门。

Answer 3

我必须引入一个附加依赖属性来在我自己的应用程序中处理这个问题：

<Grid c:GridSplitterController.Watch="{Binding ElementName=GS_DetailsView}">
    <Grid.RowDefinitions>
        <RowDefinition Height="1*" />
        <RowDefinition Height="200" />
    </Grid.RowDefinitions>

    <SomeControl Grid.Row="0" />

    <GridSplitter x:Name="GS_DetailsView"
                  Height="4"
                  Grid.Row="1"
                  VerticalAlignment="Top"
                  HorizontalAlignment="Stretch"
                  ResizeBehavior="PreviousAndCurrent"
                  ResizeDirection="Rows"
                  Visibility="{Binding ShowDetails,
                                       Converter={StaticResource boolvis}}" />

    <OtherControl Grid.Row="1"
                  Margin="0,4,0,0"
                  Visibility="{Binding ShowDetails,
                                       Converter={StaticResource boolvis}}" />
</Grid>

首先在 a 上定义一个合适的附加属性DependencyObject：

<Grid c:GridSplitterController.Watch="{Binding ElementName=GS_DetailsView}">
    <Grid.RowDefinitions>
        <RowDefinition Height="1*" />
        <RowDefinition Height="200" />
    </Grid.RowDefinitions>

    <SomeControl Grid.Row="0" />

    <GridSplitter x:Name="GS_DetailsView"
                  Height="4"
                  Grid.Row="1"
                  VerticalAlignment="Top"
                  HorizontalAlignment="Stretch"
                  ResizeBehavior="PreviousAndCurrent"
                  ResizeDirection="Rows"
                  Visibility="{Binding ShowDetails,
                                       Converter={StaticResource boolvis}}" />

    <OtherControl Grid.Row="1"
                  Margin="0,4,0,0"
                  Visibility="{Binding ShowDetails,
                                       Converter={StaticResource boolvis}}" />
</Grid>

然后听IsVisibleChanged：

public static GridSplitter GetWatch(DependencyObject obj)
{
    return (GridSplitter)obj.GetValue(WatchProperty);
}

public static void SetWatch(DependencyObject obj, GridSplitter value)
{
    obj.SetValue(WatchProperty, value);
}

public static readonly DependencyProperty WatchProperty =
    DependencyProperty.RegisterAttached(
        "Watch",
        typeof(GridSplitter),
        typeof(DependencyObject),
        new UIPropertyMetadata(null, OnWatchChanged));

一旦您监视这些更改，您需要保存或恢复GridLength您正在监视的行或列中的值（为简洁起见，我仅包括行）：

private static void OnWatchChanged(DependencyObject obj,
    DependencyPropertyChangedEventArgs e)
{
    if (obj == null) return;
    if (obj is Grid)
    {
        var grid = obj as Grid;
        var gs = e.NewValue as GridSplitter;
        if (gs != null)
        {
            gs.IsVisibleChanged += (_sender, _e) =>
                {
                    UpdateGrid(
                        grid,
                        (GridSplitter)_sender,
                        (bool)_e.NewValue,
                        (bool)_e.OldValue);
                };
        }
    }
}

剩下的就是GetPreviousand的合适实现GetNext：

// Given: static Dictionary<DependencyObject, GridLength> oldValues;
private static void UpdateGrid(Grid grid, GridSplitter gridSplitter, bool newValue, bool oldValue)
{
    if (newValue)
    {
        // We're visible again
        switch (gridSplitter.ResizeDirection)
        {
        case GridResizeDirection.Columns:
            break;
        case GridResizeDirection.Rows:
            int ridx = (int)gridSplitter.GetValue(Grid.RowProperty);
            var prev = grid.RowDefinitions.ElementAt(GetPrevious(gridSplitter, ridx));
            var curr = grid.RowDefinitions.ElementAt(GetNext(gridSplitter, ridx));
            if (oldValues.ContainsKey(prev) && oldValues.ContainsKey(curr))
            {
                prev.Height = oldValues[prev];
                curr.Height = oldValues[curr];
            }

            break;
        }
    }
    else
    {
        // We're being hidden
        switch (gridSplitter.ResizeDirection)
        {
        case GridResizeDirection.Columns:
            break;
        case GridResizeDirection.Rows:
            int ridx = (int)gridSplitter.GetValue(Grid.RowProperty);
            var prev = grid.RowDefinitions.ElementAt(GetPrevious(gridSplitter, ridx));
            var curr = grid.RowDefinitions.ElementAt(GetNext(gridSplitter, ridx));
            switch (gridSplitter.ResizeBehavior)
            {
                // Naively assumes only one type of collapsing!
                case GridResizeBehavior.PreviousAndCurrent:
                    oldValues[prev] = prev.Height;
                    prev.Height = new GridLength(1.0, GridUnitType.Star);

                    oldValues[curr] = curr.Height;
                    curr.Height = new GridLength(0.0);
                    break;
            }
            break;
        }
    }
}