柯于旺 · 更新于 2018-11-28 11:00:43

为 ListView 和 GridView 添加分组

本文承接“为 ListView 和 GridView 添加数据”。

在上一节中我们已经了解了怎样将数据绑定到 ListView 或 GridView,但既然要用到这两个控件往往是因为数据繁多,那么几乎就不可避免的要让其能够分组。我们所绑定的数据源可能是项列表,其中的每个项甚至还有其自己的项,那么问题就来了。

一时不会也想不出什么宏伟的例子,就做一个简单的闹钟的时间表的 ListView 和 GridView 吧。那么先在项目中添加一个类,最好在 Shared 下。内容都是很简易的,闹钟的标题、时间、备注等,为了增加一级目录就加了一个 AlarmMode,就算作学习和生活吧,学习生活两不误……

public class Alarm
{
    public string Title { get; set; }
    public DateTime AlarmClockTime { get; set; }
    public string Description { get; set; }
    public string AlarmMode { get; set; }
}
public class AlarmMode
{
   public AlarmMode()
   {
       alarmMode = new ObservableCollection<Alarm>();
   }
   public string Name { get; set; }
   public ObservableCollection<Alarm> alarmMode { get; private set; }
}

首先,先来定义一个全局的时间,然后在页面加载时加载两个函数(将在下一步定义)。

DateTime globalTime;
protected override void OnNavigatedTo(NavigationEventArgs e)
{
    DateTime.TryParse("1/1/2115", out globalTime);
    AddAlarm();
    AddAlarmMode();
}

一大波数据正在靠近!

private void AddAlarm()
{
    List<Alarm> listAlarm = new List<Alarm>();
    listAlarm.Add(new Alarm()
    {
        Title = "Alarm1",
        Description = "First Alarm",
        AlarmClockTime = globalTime.AddHours(1),
        AlarmMode = "Alarm In Life"
    });
    listAlarm.Add(new Alarm()
    {
        Title = "Alarm2",
        Description = "Second Alarm",
        AlarmClockTime = globalTime.AddHours(11),
        AlarmMode = "Alarm In Life"
    });
    listAlarm.Add(new Alarm()
    {
        Title = "Alarm3",
        Description = "Third Alarm",
        AlarmClockTime = globalTime.AddDays(1),
        AlarmMode = "Alarm In Life"
    });
    listAlarm.Add(new Alarm()
    {
        Title = "Alarm1",
        Description = "First Alarm",
        AlarmClockTime = globalTime.AddHours(12),
        AlarmMode = "Alarm In Study"
    });
    listAlarm.Add(new Alarm()
    {
        Title = "Alarm2",
        Description = "Second Alarm",
        AlarmClockTime = globalTime.AddHours(15),
        AlarmMode = "Alarm In Study"
    });
    listAlarm.Add(new Alarm()
    {
        Title = "Alarm3",
        Description = "Third Alarm",
        AlarmClockTime = globalTime.AddMonths(1),
        AlarmMode = "Alarm In Study"
    });
    ar alarmSetting = from ala in listAlarm
                       group ala
                       by ala.AlarmMode
                       into alaSetting
                       orderby alaSetting.Key
                       select alaSetting;
    collectionVSAlarm.Source = alarmSetting;
}
private void AddAlarmMode()
{
    List<AlarmMode> listAlarmMode = new List<AlarmMode>();
    AlarmMode am1 = new AlarmMode();
    am1.Name = "Alarm In Life";
    am1.alarmMode.Add(new Alarm()
    {
        Title = "Alarm1",
        Description = "First Alarm",
        AlarmClockTime = globalTime.AddHours(1),
    });
    am1.alarmMode.Add(new Alarm()
    {
        Title = "Alarm2",
        Description = "Second Alarm",
        AlarmClockTime = globalTime.AddHours(11),
    });
    am1.alarmMode.Add(new Alarm()
    {
        Title = "Alarm3",
        Description = "Third Alarm",
        AlarmClockTime = globalTime.AddDays(1),
    });
    listAlarmMode.Add(am1);
    AlarmMode am2 = new AlarmMode();
    am2.Name = "Alarm In Study";
    am2.alarmMode.Add(new Alarm()
    {
        Title = "Alarm1",
        Description = "First Alarm",
        AlarmClockTime = globalTime.AddHours(12),
    });
    am2.alarmMode.Add(new Alarm()
    {
        Title = "Alarm2",
        Description = "Second Alarm",
        AlarmClockTime = globalTime.AddHours(15),
    });
    am2.alarmMode.Add(new Alarm()
    {
        Title = "Alarm3",
        Description = "Third Alarm",
        AlarmClockTime = globalTime.AddMonths(1),
    });
    listAlarmMode.Add(am2);
    collectionVSAlarmMode.Source = listAlarmMode;
}

这些数据都是乱七八糟啦,大家凑合着看。这是两个函数,数据我都是用 List<> 来定义的,将数据通过 Add 函数添加到 listAlarm 和 listAlarmMode 中即可。最后再从 listAlarm 中根据 AlarmMode 挑出数据到 alaSetting,同时还要根据 Key 值进行排序最后选出并连接到collectionVSAlarm的 Source 属性中。这个是需要在 MainPage.xaml 中定义的哦,就像 <Page.Resource/> 一样。还需要 ItemsPath 属性来定义其的子对象哟。

    <UserControl.Resources>
        <CollectionViewSource x:Name="collectionVSAlarm"     IsSourceGrouped="True"/>
        <CollectionViewSource x:Name="collectionVSAlarmMode"     IsSourceGrouped="True" ItemsPath="alarmMode"/>
    </UserControl.Resources>

然后我们还需要创建一个 ListGridGroupStyle 类来继承 GroupStyleSelector,重载它的 SelectGroupStyleCore 方法,并且返回 ListGridGroupStyleResource 资源,这个资源在博客后文中有定义,其定义在 App.xaml 中。相应的代码如下咯:

    public class ListGridGroupStyle : GroupStyleSelector
    {
        protected override GroupStyle SelectGroupStyleCore(object group, uint level)
        {
            return (GroupStyle)App.Current.Resources["ListGridGroupStyleResource"];
        }
    }

方法重载好之后就需要在前面的 UserControl.Resources 中加上以下这条代码啦。

    <local:ListGridGroupStyle x:Key="ListGridGroupStyleResource"/>

然后我们来一系列的基本样式到 App.xaml 中就好啦,关于资源文件的使用我们在后面会系统的来学习。这里的 DataTemplate 和 GroupStyle 都在资源字典中,前者是 Template 模板,后者是 Style 风格。内容的排版大家都随意啦,记得设置好 Key 值。

    <Application.Resources>
        <ResourceDictionary>
            <DataTemplate x:Key="dataTemplateListView">
                <StackPanel Width="700" Margin="10">
                    <StackPanel Orientation="Horizontal">
                        <TextBlock Text="{Binding Title}" FontWeight="Bold" Margin="12"/>
                        <TextBlock Text="{Binding AlarmClockTime}" TextWrapping="NoWrap" Margin="12"/>
                        <TextBlock Text="{Binding Description}" TextWrapping="NoWrap" Margin="12"/>
                    </StackPanel>             
                </StackPanel>
            </DataTemplate>
            <GroupStyle x:Key="ListGridGroupStyleResource">
                <GroupStyle.HeaderTemplate>
                    <DataTemplate>
                        <Grid Background="LightGray"  >
                            <TextBlock Text='{Binding Key}' Foreground="CornflowerBlue" Margin="12"  />
                        </Grid>
                    </DataTemplate>
                </GroupStyle.HeaderTemplate>
            </GroupStyle>
        </ResourceDictionary>
    </Application.Resources>

那么这些各种资源都定义好了之后就在 MainPage.xaml 把下面这些敲进去。各种资源的调用在这里尤其需要注意,其实对于稍微复杂一丁点的程序而言,名称就已经变得让人崩溃了。所以拥有一个良好的命名习惯很重要。

    <Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="auto"/>
            <ColumnDefinition Width="auto"/>
        </Grid.ColumnDefinitions>
        <GridView Grid.Column="0" ItemsSource="{Binding Source={StaticResource collectionVSAlarmMode}}"        
                  Margin="12,120,12,12" MaxHeight="600" >
            <GridView.ItemTemplate>
                <DataTemplate>
                    <StackPanel Margin="18">
                        <TextBlock Text="{Binding Title}" FontWeight="ExtraBold"   />
                        <TextBlock Text="{Binding AlarmClockTime}"  FontWeight="Light" TextWrapping="NoWrap"  />
                        <TextBlock Text="{Binding Description}" TextWrapping="NoWrap"  />
                    </StackPanel>
                </DataTemplate>
            </GridView.ItemTemplate>
            <GridView.ItemsPanel>
                <ItemsPanelTemplate>
                    <ItemsWrapGrid MaximumRowsOrColumns="2"/>
                </ItemsPanelTemplate>
            </GridView.ItemsPanel>
            <GridView.GroupStyle>
                <GroupStyle>
                    <GroupStyle.HeaderTemplate>
                        <DataTemplate>
                            <Grid Background="Green" Margin="12">
                                <TextBlock Text='{Binding Name}' 
                                           Foreground="Bisque" Margin="36"/>
                            </Grid>
                        </DataTemplate>
                    </GroupStyle.HeaderTemplate>    
                </GroupStyle>
            </GridView.GroupStyle>
        </GridView>
        <ListView Grid.Column="1" ItemsSource="{Binding Source={StaticResource collectionVSAlarm}}"     
                  ItemTemplate="{StaticResource dataTemplateListView}"    
                  GroupStyleSelector="{StaticResource ListGridGroupStyleResource}"          
                  Margin="120" />       
    </Grid>

这里写图片描述

我这写的真是太丑了哎,做产品的时候可得好好调调了。