转载: http://www.kecq.com/artic-10322303.html

以前做了一个数据客户端,不过是直接连数据库的,现在认为这种方式不太好,于是改成服务端RESTful API+客户端,数据处理都在服务端。在编写过程中遇到一些问题,因为之前没有采用分页,所以排序就用DataGrid默认的就行,但是现在需要在服务端分页了,就发现了一些问题,记录下来。

在XAML中有一个名为dataGrid1的DataGrid,点击列头排序只需要在上面加上Sorting属性

<DataGrid  Grid.Row="2" x:Name="dataGrid1" AutoGenerateColumns="False" IsReadOnly="True"  AlternationCount="2" Sorting="dataGrid1_Sorting"  >

初始化的时候可以为某一列指定排序

 ICollectionView view = CollectionViewSource.GetDefaultView(list);
 view.SortDescriptions.Clear();  //先清除所有的排序
 SortDescription sd = new SortDescription("列名",  ListSortDirection.Descending);
 view.SortDescriptions.Add(sd);

也可以在XAML中指定,假设列名是movieName

<DataGrid.Columns>

  <DataGridTextColumn Binding="{Binding Path=movieName}"     SortDirection="Ascending" SortMemberPath="movieName"  Header="名称"   />

</DataGrid.Columns>

下面来看主要排序方法

private void dataGrid1_Sorting(object sender, DataGridSortingEventArgs e)
            e.Handled = true;    //可要可不要  没去仔细研究
            pager.OrderColumn = e.Column.SortMemberPath;
            ICollectionView view = CollectionViewSource.GetDefaultView(dataGrid1.ItemsSource);
            pager.Order = "asc";  //默认升序
            if (view.SortDescriptions.Count>0)
                if(view.SortDescriptions[0].PropertyName== e.Column.SortMemberPath)
                    if (view.SortDescriptions[0].Direction == System.ComponentModel.ListSortDirection.Ascending)
                        pager.Order = "desc";
                    else if (view.SortDescriptions[0].Direction == ListSortDirection.Descending)
                        pager.Order = "asc";
            LoadData();

e.Column.SortMemberPath 为点击列头的列名,问题就在e.Column.SortDirection 这个属性,如果初始化的时候有指定那么第一次点击的时候能获取到,但是再点击这个属性就是null了,没有指定也是null,好了,我在这里为它赋值e.Column.SortDirection=ListSortDirection.Descending    但是下次点击的时候它还是为null 不知为何,网上没有查到。经过好久摸索,用另一个方法来

ICollectionView view = CollectionViewSource.GetDefaultView(dataGrid1.ItemsSource);

可以从view.SortDescriptions 中取得有排序的列,判断它集合大于0并且列名是当前点击的列,如果当前是升序则变为降序同时查询降序的数据,当然最后还得执行清除排序再添加排序

view.SortDescriptions.Clear();  //先清除所有的排序
 SortDescription sd = new SortDescription("列名",  ListSortDirection.Descending);
 view.SortDescriptions.Add(sd);

这样就实现了服务端排序,不知有无更简单的方法。

文中提到:我在这里为它赋值e.Column.SortDirection=ListSortDirection.Descending,。这里实际效果重新绑定数据后会丢失以前的排序。应该在绑定数据后再重新绑定列的排序状态

所以我这里这样处理的,

1、后端记录上次的排序状态 某列名 升序还是降序

2、绑定数据后,再次赋值当前的排序状态。swich记录的当前排序也就是重新绑定数据前的排序,case某列的排序状态,然后gridResult2.Columns[2].SortDirection重新设置此列的排序状态值。这样就能在​DataGridSortingEventArgs e  ​ e.Column.SortDirection 属性中获取到重新设置的排序值。这样重新赋值,也能显示自带的排序小箭头。不明白的可以联系www.kaishanguai.com或qq369628105​

 switch (CurrentOrderByEnum)
                {
                    case (OrderByEnum.OrderByNameAsc):
                        gridResult2.Columns[2].SortDirection = ListSortDirection.Ascending;
                        break;

                    case (OrderByEnum.OrderByNameDesc):
                        gridResult2.Columns[2].SortDirection = ListSortDirection.Descending;
                        break;

                                <DataGrid x:Name="gridResult2" SelectionUnit="FullRow"  MinHeight="420"    EnableRowVirtualization ="False" GridLinesVisibility="None"  BorderThickness="0" AlternationCount="2" ItemsSource="{Binding}"  CanUserAddRows="False" HorizontalAlignment="Left"  VerticalAlignment="Top" AutoGenerateColumns="False" Visibility="Hidden"    IsReadOnly="True" SelectionMode="Extended"  Sorting="GridResult2_OnSorting"  MouseMove="GridResult2_OnMouseMove" MouseLeftButtonDown="GridResult2_OnMouseLeftButtonDown"  MouseLeftButtonUp="GridResult2_OnMouseLeftButtonUp" MouseRightButtonUp="ImageGrid_OnMouseRightButtonDown" LoadingRow="GridResult2_OnLoadingRow"   KeyDown="DataView_OnKeyDown" PreviewKeyDown="GridResult2_OnPreviewKeyDown">
                                    <!--SelectionChanged="GridResult2_OnSelectionChanged"  -->
                                    <!-- This is required to handle CTRL + C when something is selected in the DataGrid -->
                                    <DataGrid.CommandBindings>
                                        <CommandBinding Command="Copy" Executed="CopyCommand" />
                                    </DataGrid.CommandBindings>
                                    <!-- This is required to handle CTRL + C when something is selected in the DataGrid -->
                                    <DataGrid.InputBindings>
                                        <KeyBinding Key="C" Modifiers="Control" Command="Copy" />
                                    </DataGrid.InputBindings>
                                    <DataGrid.Columns>
                                        <DataGridTemplateColumn>
                                            <DataGridTemplateColumn.HeaderTemplate>
                                                <DataTemplate>
                                                    <CheckBox  Name="ChkAll" ToolTip="All"  Content="All"   IsChecked="False" Unchecked="UnAll_Checked" Checked="All_Checked"></CheckBox>
                                                </DataTemplate>
                                            </DataGridTemplateColumn.HeaderTemplate>
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <CheckBox   Checked="ItemFile_OnChecked"  Unchecked="ItemFile_OnUnchecked" Tag="{Binding FilePath}" HorizontalAlignment="Center" x:Name="itemFile"   VerticalAlignment="Center" />
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                        <DataGridTemplateColumn  Header="">
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <Image Source="{Binding SnapshotPath}" Height="20" Width="20" />
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                        <DataGridTextColumn Header="Name" Binding="{Binding FileName}" />
                                        <DataGridTemplateColumn  Header="MD5">
                                            <DataGridTemplateColumn.HeaderStyle>
                                                <Style TargetType="DataGridColumnHeader">
                                                    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
                                                </Style>
                                            </DataGridTemplateColumn.HeaderStyle>
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <TextBlock HorizontalAlignment="Center" Text="{Binding FileMD5}"></TextBlock>
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                        <DataGridTemplateColumn  Header="Modified Date" CanUserSort="True" SortMemberPath="FileModifiedTime">
                                            <DataGridTemplateColumn.HeaderStyle>
                                                <Style TargetType="DataGridColumnHeader">
                                                    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
                                                </Style>
                                            </DataGridTemplateColumn.HeaderStyle>
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <TextBlock HorizontalAlignment="Center" Text="{Binding FileModifiedTime}"></TextBlock>
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                        <DataGridTextColumn Header="Path" Binding="{Binding FilePathNoName}" />
                                        <DataGridTemplateColumn  Header="Classify Type"  CanUserSort="True" SortMemberPath="ClassifyType">
                                            <DataGridTemplateColumn.HeaderStyle>
                                                <Style TargetType="DataGridColumnHeader">
                                                    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
                                                </Style>
                                            </DataGridTemplateColumn.HeaderStyle>
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <TextBlock HorizontalAlignment="Center" Text="{Binding ClassifyType}"></TextBlock>
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                        <DataGridTemplateColumn  Header="Type">
                                            <DataGridTemplateColumn.HeaderStyle>
                                                <Style TargetType="DataGridColumnHeader">
                                                    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
                                                </Style>
                                            </DataGridTemplateColumn.HeaderStyle>
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <TextBlock HorizontalAlignment="Center" Text="{Binding FileExtension}"></TextBlock>
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                        <DataGridTemplateColumn  Header="Size(KB)" CanUserSort="True"  SortMemberPath="FileSize">
                                            <DataGridTemplateColumn.HeaderStyle>
                                                <Style TargetType="DataGridColumnHeader">
                                                    <Setter Property="HorizontalContentAlignment" Value="Center"></Setter>
                                                </Style>
                                            </DataGridTemplateColumn.HeaderStyle>
                                            <DataGridTemplateColumn.CellTemplate>
                                                <DataTemplate>
                                                    <TextBlock HorizontalAlignment="Center" Text="{Binding FileSize, StringFormat={}{0:N0}}"></TextBlock>
                                                </DataTemplate>
                                            </DataGridTemplateColumn.CellTemplate>
                                        </DataGridTemplateColumn>
                                    </DataGrid.Columns>
                                </DataGrid>
//绑定数据后,重新设置排序状态     
gridResult2.ItemsSource = bindDataList; //设置排序图标 if (IsClickSort) switch (CurrentOrderByEnum) case (OrderByEnum.OrderByNameAsc): gridResult2.Columns[2].SortDirection = ListSortDirection.Ascending ; break; case (OrderByEnum.OrderByNameDesc): gridResult2.Columns[2].SortDirection = ListSortDirection.Descending; break; case (OrderByEnum.OrderByModifiedDateAsc): gridResult2.Columns[4].SortDirection = ListSortDirection.Ascending ; break; case (OrderByEnum.OrderByModifiedDateDesc): gridResult2.Columns[4].SortDirection = ListSortDirection.Descending; break; case (OrderByEnum.OrderByClassifyAsc): gridResult2.Columns[6].SortDirection = ListSortDirection.Ascending; break; case (OrderByEnum.OrderByClassifyDesc): gridResult2.Columns[6].SortDirection = ListSortDirection.Descending ; break; case (OrderByEnum.OrderBySizeAsc): gridResult2.Columns[8].SortDirection = ListSortDirection.Ascending; break; case (OrderByEnum.OrderBySizeDesc): gridResult2.Columns[8].SortDirection = ListSortDirection.Descending; break; gridResult2.Columns[4].SortDirection = ListSortDirection.Descending;
 
//排序事件
private void GridResult2_OnSorting(object sender, DataGridSortingEventArgs e) ListSortDirection direction = (e.Column.SortDirection != ListSortDirection.Ascending) ? ListSortDirection.Ascending : ListSortDirection.Descending; bool sortAscending = direction == ListSortDirection.Ascending; switch (e.Column.SortMemberPath) case ("FileName"): if (sortAscending) CurrentOrderByEnum = OrderByEnum.OrderByNameAsc; CurrentOrderByEnum = OrderByEnum.OrderByNameDesc; break; case ("FileModifiedTime"): if (sortAscending) CurrentOrderByEnum = OrderByEnum.OrderByModifiedDateAsc; CurrentOrderByEnum = OrderByEnum.OrderByModifiedDateDesc; break; case ("ClassifyType"): if (sortAscending) CurrentOrderByEnum = OrderByEnum.OrderByClassifyAsc; CurrentOrderByEnum = OrderByEnum.OrderByClassifyDesc; break; case ("FileSize"): if (sortAscending) CurrentOrderByEnum = OrderByEnum.OrderBySizeAsc; CurrentOrderByEnum = OrderByEnum.OrderBySizeDesc; break; IsClickSort = true; Search();