信息系统开发平台OpenExpressApp － 支持列表分组(Group)

　　在《内置支持的列表编辑方式》中介绍了OpenExpressApp内置的列表编辑方式。由于在列表显示过程中，经常会遇到需要分组显示的需求，所以OEA也内置了列表分组功能（暂时还不支持多对象树分组），与框架结合起来，完成这个功能更简单友好。本篇介绍一下OEA对列表分组的支持。

界面

　　设置分组后，AutoUI自动生成如下所示界面：每一组之上显示一条记录，左边为上下箭头，点击后可以展开和折叠分组的内容，右边显示分组依据属性和当前分组的条目数目。

类库编写

　　只需要在显示对象类型定义的BusinessObjectAttribute加上属性PropertyGroup，系统支持多个分组， 属性值为一个带分隔符‘；’的属性名称字符串列表，AutoUI会自动根据分组属性来构建列表界面，显示结果如上图所示，以下为代码片段：

    [BusinessObject(ModuleType = ModuleType.List, PropertyGroup= "ProjectName"), Label("清单查询")]
    public partial class SingleBq : GBusinessBase<SingleBq>
    {
        public string ProjectName
        {
            get
            {
                return ProjectInfo.Name;
            }
        }
        
    }

分组样式文件

　　参考了《WPF － DataGrid 相关收集》中的WPF DataGrid Practical Examples，这个例子列举了很多微软DataGrid的使用，分组是参考Style完全版的那个页面中的Group样式而完成的。如果想学习这个，大家必须先对样式文件、WPF的分组有所了解，网上这类文章也很多，这里也不重复了。以下为样式：

<ResourceDictionary 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <!-- style the expander toggle button -->
    <ControlTemplate x:Key="ExpanderToggleButton" TargetType="ToggleButton">
        <Border>
            <Path Name="Arrow" Fill="Black" HorizontalAlignment="Center" VerticalAlignment="Center"
                      Data="M 0 0 L 6 8 L 12 0 Z"/>
        </Border>
        <ControlTemplate.Triggers>
            <Trigger Property="IsChecked" Value="true">
                <Setter TargetName="Arrow" Property="Data" Value="M 0 8 L 6 0 L 12 8 Z" />
            </Trigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>
    <!-- expander styled to give a full width header and to provide access to the toggle button -->
    <Style  TargetType="Expander">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="Expander">
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Name="ContentRow" Height="0"/>
                        </Grid.RowDefinitions>
                        <Border Name="Border" Grid.Row="0">
                            <Grid>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="20" />
                                    <ColumnDefinition Width="*" />
                                </Grid.ColumnDefinitions>
                                <ToggleButton IsChecked="{Binding Path=IsExpanded,Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"
                                            OverridesDefaultStyle="True" Template="{StaticResource ExpanderToggleButton}" />
                                <ContentPresenter Grid.Column="1" Margin="4" ContentSource="Header" RecognizesAccessKey="True" />
                            </Grid>
                        </Border>
                        <Border Name="Content"  Grid.Row="1" Background="Transparent" BorderThickness="0">
                            <ContentPresenter Margin="3,0,0,0" />
                        </Border>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger Property="IsExpanded" Value="True">
                            <Setter TargetName="ContentRow" Property="Height" Value="{Binding ElementName=Content, Path=DesiredHeight}" />
                        </Trigger>
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

    <!-- a grouping style that uses an expander to render the rouped data -->
    <Style x:Key="GroupContainerStyle" TargetType="{x:Type GroupItem}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type GroupItem}">
                    <Expander IsExpanded="True">
                        <Expander.Header>
                            <Grid>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="Auto"/>
                                    <ColumnDefinition />
                                </Grid.ColumnDefinitions>
                                <Grid.RowDefinitions>
                                    <RowDefinition/>
                                </Grid.RowDefinitions>
                                <StackPanel Orientation="Horizontal"  Margin="0,0,10,0">
                                    <TextBlock Text="{Binding Path=Name}" FontWeight="Bold" />
                                    <TextBlock FontWeight="Bold" Text="{Binding Path=ItemCount, StringFormat=(共{0}条)}"/>
                                </StackPanel>
                                <Line Grid.Column="1" SnapsToDevicePixels="true"  X1="0" X2="1" Stretch="Fill"  StrokeThickness="1"/>
                            </Grid>
                        </Expander.Header>
                        <ItemsPresenter />
                    </Expander>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>

OpenExpressApp对分组支持的实现

1. 元信息支持分组支持
   
       [AttributeUsage(AttributeTargets.Class)]
       public class BusinessObjectAttribute : Attribute
       {
           //默认分组
           public string PropertyGroup { get; set; }
           
       }
2. 业务模型增加GroupDescriptions  
       /// <summary>
       /// 业务对象模型
       /// </summary>
       public class BusinessObjectInfo
       {
           /// 默认分组属性值
           public string[] GroupDescriptions;
   
           public BusinessObjectInfo(Type boType)
           {
               this.BOType = boType;
               BusinessObjectAttribute = boType.GetSingleAttribute<BusinessObjectAttribute>();
   
               if (!String.IsNullOrEmpty(BusinessObjectAttribute.PropertyGroup))
                   GroupDescriptions = BusinessObjectAttribute.PropertyGroup.Split(';');
               
           }
       }     
   
   
   
3. 把上面的样式存为文件Resource.xaml，在系统模块ExpressAppWPFModule的初始化方法中增加装载样式文件，代码如下：
   
               resouceDic = Application.LoadComponent(new Uri("OpenExpressApp.Module.WPF;component/Resources/Resource.xaml", UriKind.Relative)) as ResourceDictionary;
               Application.Current.Resources.MergedDictionaries.Insert(0, resouceDic);
4. 增加以前的AutoUI.CreateListControl代码，设置GroupStyle
         public static object CreateListControl(Type boType, ListObjectView view)
           {
               DataGrid dg = new SelectionDataGrid()
                   {
                       CanUserAddRows = false,
                       AutoGenerateColumns = false,
                       VerticalGridLinesBrush = new SolidColorBrush(Colors.Gray),
                       HorizontalGridLinesBrush = new SolidColorBrush(Colors.Gray),
                   };
               GroupStyle gs = new GroupStyle();
               gs.ContainerStyle = Application.Current.TryFindResource("GroupContainerStyle") as Style;
               dg.GroupStyle.Add(gs);
   　　　　 ...
   　　　}
   
5. 修改ListEditor.OnSetData，设置collectionView.GroupDescriptions
           public virtual void OnSetData()
           {
               ICollectionView collectionView = CollectionViewSource.GetDefaultView(View.Data);
               if (null != collectionView)
               {
                   string[] groups = ApplicationModel.GetBusinessObjectInfo(BOType).GroupDescriptions;
                   if (null != groups)
                   {
                       foreach (string propertyName in groups)
                           collectionView.GroupDescriptions.Add(new PropertyGroupDescription(propertyName));
                   }
               }
               dg.ItemsSource = collectionView;
           }

更多内容： 开源信息系统开发平台之OpenExpressApp框架.pdf