对 DataGrid 组进行排序

我有一个非常基本的DataGrid以及一些测试数据。数据作为ObservableCollection<T> of Client objects， 其中包含Organization, FirstName and LastName特性。我将项目分组为Organization并希望能够排序FirstName and LastName在特定组内（这部分功能正常），并且还对组本身进行排序Organization。最后一部分是我遇到问题的部分。

如果我没有指定任何排序属性或者如果我指定了属性CollectionViewSource.SortDescriptions（见下文），例如PropertyName="Name" or PropertyName="CompleteNonsense"， 除了PropertyName="Organization"，它会让我进行初始排序。如果您查看下图，会发现公司名称的显示顺序是乱序的，因为这就是集合的初始化方式。如果我点击Organizationheader，它会按升序对其进行排序，但之后不会再让我进行任何排序。如果我再次单击标题，它会更改指示排序方向的箭头，但不会发生实际排序。无论我指定什么排序属性，都会执行相同的操作...即使是完全任意的属性，除非它是PropertyName="Organization"，或者如果没有指定属性。

如果我指定排序PropertyName="Organization"，它将开始按升序排序，但如果单击标题则不会排序。因此，该属性名称似乎确实触发了排序，但只是第一次。

截屏：

这是XAML为了DataGrid:

<DataGrid ItemsSource="{Binding Source={StaticResource GroupedData}}" 
          AutoGenerateColumns="False" IsReadOnly="True" 
          GridLinesVisibility="None" HeadersVisibility="Column" 
          CanUserAddRows="False" CanUserDeleteRows="False"
          CanUserResizeRows="False" Background="White">
    <DataGrid.CellStyle>
        <Style TargetType="DataGridCell">
            <Setter Property="BorderThickness" Value="0"/>
        </Style>
    </DataGrid.CellStyle>
    <DataGrid.RowStyle>
        <Style TargetType="DataGridRow">
            <Setter Property="Margin" Value="10,0,0,0"/>
        </Style>
    </DataGrid.RowStyle>
    <DataGrid.GroupStyle>
        <GroupStyle>
            <GroupStyle.HeaderTemplate>
                <DataTemplate>
                    <DockPanel Background="LightBlue" DataContext="{Binding Items}">
                        <TextBlock Text="{Binding Path=Organization}" 
                                   Foreground="Blue" Margin="5,0,0,0" Width="100"/>
                        <TextBlock Text="Employee Count:" Foreground="Blue" Margin="40,0,0,0"/>
                        <TextBlock Text="{Binding Path=Count}" Foreground="Blue" 
                                   Margin="5,0,0,0"/>
                    </DockPanel>
                </DataTemplate>
            </GroupStyle.HeaderTemplate>
        </GroupStyle>
    </DataGrid.GroupStyle>
    <DataGrid.Columns>
        <DataGridTextColumn Header="Organization" Binding="{Binding Organization}"/>
        <DataGridTextColumn Header="First Name" Binding="{Binding FirstName}"/>
        <DataGridTextColumn Header="Last Name" Binding="{Binding LastName}"/>
        <DataGridTextColumn Width="*"/>
    </DataGrid.Columns>
</DataGrid>

这是XAML为了Grouping and Sorting:

<CollectionViewSource Source="{Binding Data}" x:Key="GroupedData">
    <CollectionViewSource.GroupDescriptions>
        <PropertyGroupDescription PropertyName="Organization"/>
    </CollectionViewSource.GroupDescriptions>
    <CollectionViewSource.SortDescriptions>
        <scm:SortDescription PropertyName="Organization"/>
    </CollectionViewSource.SortDescriptions>
</CollectionViewSource>

有谁知道我如何实现组的排序Organization超出了最初的排序？

EDIT:

我一直在搞乱这个（真的需要弄清楚这一点）并为标题创建了一个快速的代码隐藏事件处理程序Click event:

<DataGrid.ColumnHeaderStyle>
    <Style TargetType="DataGridColumnHeader">
        <EventSetter Event="Click" Handler="ColumnHeader_Click"/>
    </Style>
</DataGrid.ColumnHeaderStyle>

private void ColumnHeader_Click(object sender, RoutedEventArgs e)
{
    var columnHeader = sender as DataGridColumnHeader;
    if (columnHeader != null && columnHeader.Content.ToString().Equals("Organization"))
    {
        if (columnHeader.Column.SortDirection == ListSortDirection.Descending)
        {
            columnHeader.Column.SortDirection = ListSortDirection.Ascending;
            MessageBox.Show("Ascending");
        }
        else
        {
            columnHeader.Column.SortDirection = ListSortDirection.Descending;
            MessageBox.Show("Descending");
        }
    }
}

每次点击后Organization, "Descending"弹出，排序箭头指向下方，点击后OK，它立即恢复到指向上方。组的实际排序永远不会在视觉上进行。有什么东西让它卡在一个Ascending order.

Note：参见Edit获取最新代码。

这有点棘手，但我找到了答案。下面的代码用于代码隐藏处理程序Sorting事件，但可以轻松调整以放置在ViewModel or View（取决于你如何做事）。

Code:

<DataGrid Sorting="DataGrid_Sorting" ... > ... </DataGrid>

private void DataGrid_Sorting(object sender, DataGridSortingEventArgs e)
{
    var headerName = "Organization";

    var column = e.Column;
    if (!column.Header.ToString().Equals(headerName))
    {
        return;
    }

    var source = (sender as System.Windows.Controls.DataGrid).ItemsSource as ListCollectionView;
    if (source == null)
    {
        return;
    }

    e.Handled = true;
    var sortDirection = column.SortDirection == ListSortDirection.Ascending ? 
        ListSortDirection.Descending : ListSortDirection.Ascending;

    using (source.DeferRefresh())
    {
        source.SortDescriptions.Clear();
        source.SortDescriptions.Add(new SortDescription(headerName, sortDirection));
    }
    source.Refresh();
    column.SortDirection = sortDirection;
}

使用上面的代码，组本身按以下方式排序Organization每组中的项目按以下顺序排序FirstName and LastName。希望这段代码对其他人有帮助。我一整天都在四处寻找，这似乎是人们在与群体打交道时面临的一个常见问题DataGrid.

唯一的缺点是，当组项目按分组属性以外的任何方式排序时，它会将组的顺序重置为默认值。在尝试了很多代码之后，我一直无法找到解决方案。如果有人找到该部分的解决方案，我很乐意给他们“正确答案”。

一些对我有帮助的资源：

如何在 WPF 中强制 DataGrid 组顺序？ https://stackoverflow.com/a/10365727/2006048
WPF Datagrid 分组和排序 https://stackoverflow.com/a/16054823/2006048

EDIT:

弄清楚了关于组间排序被组内排序重置的最后一部分。这有点乱，因为我没有时间清理它，但我想我应该分享我的代码：

<CollectionViewSource.GroupDescriptions>
    <PropertyGroupDescription PropertyName="Organization"/>
</CollectionViewSource.GroupDescriptions>
<CollectionViewSource.SortDescriptions>
    <scm:SortDescription PropertyName="Organization" Direction="Ascending"/>
    <scm:SortDescription PropertyName="FirstName" Direction="Ascending"/>
    <scm:SortDescription PropertyName="LastName" Direction="Ascending"/>
</CollectionViewSource.SortDescriptions>

private void DataGrid_Sorting(object sender, DataGridSortingEventArgs e)
{
    SortGroupedDataGrid("Organization", sender, e);
}

private void SortGroupedDataGrid(string groupHeader, object sender, DataGridSortingEventArgs e)
{
    // Get the main ListCollectionView and make sure it's not null.
    var source = (sender as System.Windows.Controls.DataGrid).ItemsSource as ListCollectionView;
    if (source == null)
    {
        return;
    }

    // Mark event as handled, so that automated sorting would not take place.
    e.Handled = true;
    // Main header which was used for the grouping.  I'm only using one, but more can be added.
    var headerName = groupHeader;
    // Get the column that was being sorted on.
    var column = e.Column;
    // Check if the column was the same as the one being used for the grouping.
    // I remove spaces so that any properties I use match the headers.  Regex would probably
    // work just as well, but it's an overkill for me at this time.
    var isMainHeader = column.Header.ToString().Replace(" ", "").Equals(headerName);
    // Because I set the initial sorting for all the properties in the XAML to be
    // be sorted in Ascending order, I set these ones to Descending.  One is for
    // the main column and the other is for the secondary column.  This does not account
    // for a case where user Shift + Clicks multiple columns to chain sort.
    var mainSortDirection = ListSortDirection.Descending;
    var secondarySortDirection = ListSortDirection.Descending;

    // If this is a main column sort event...
    if (isMainHeader)
    {
        // Check its sorting direction and set it as opposite.
        mainSortDirection = column.SortDirection == ListSortDirection.Descending ?
            ListSortDirection.Ascending : mainSortDirection;
    }
    else
    {
        // ...else, get the sorting direction of the main column, because we want
        // it to stay the same, and get the opposite sorting direction for the
        // secondary column.
        mainSortDirection = source.SortDescriptions[0].Direction;
        secondarySortDirection = column.SortDirection == ListSortDirection.Descending ?
            ListSortDirection.Ascending : secondarySortDirection;
    }

    // Defer refreshing of the DataGrid.
    using (source.DeferRefresh())
    {
        // Clear any existing sorts.  I've had some issues trying to alter existing ones.
        source.SortDescriptions.Clear();
        // Since we want main column to either alter if its sort event was called, or
        // stay the same if secondary column event was called, we always set it first.
        source.SortDescriptions.Add(new SortDescription(headerName, mainSortDirection));

        // If this was not a main column event...
        if (!isMainHeader)
        {
            // ...then set sorting for that other column. Since it'll be at index 1, 
            // after the main one, it'll only sort within each group, as I wanted.
            source.SortDescriptions.Add(new SortDescription(column.Header.ToString().Replace(" ", ""), secondarySortDirection));
            // Set the header direction as well.
            column.SortDirection = secondarySortDirection;
        }
        else
        {
            // Otherwise, it's a main event and we want to show the error for its header.
            // If you want primary sorting direction to always display, then simply take
            // it outside of else scope, so that it's always assigned.
            column.SortDirection = mainSortDirection;
        }
    }
    // Now we can refresh and post changes.
    source.Refresh();
}