Win8中GridVIew千变万化——绑定分组数据

sdchy

　　今天和大家探讨下GridView如何绑定分组数据的例子。
　　要实现分组绑定数据主要两个步骤：
1、创建创建CollectionViewSource并且绑定（这里可以使用两种类型的数据作为数据源，一种使用Linq，另一种使用的时集合中包含集合数据）；
2、设置GroupStyle的相关属性和样式。
　　第一步：创建集合数据源



public sealed partial class Group : Page
{
CollectionViewSource cvsActivities;//, cvsProjects;
DateTime startDate;//一个界定时间
public Group()
{
this.InitializeComponent();
}
protected override void OnNavigatedTo(NavigationEventArgs e)
{
DateTime.TryParse("1/1/2014", out startDate);//初始化一个界定时间

cvsActivities = new CollectionViewSource();
InitActivities();
//cvsActivities.Source = InitActivities();
cvsActivities.IsSourceGrouped = true;
listView.ItemsSource = cvsActivities.View;
CollectionViewSource cvsProjects = new CollectionViewSource();
cvsProjects.Source = InitProjects();
cvsProjects.IsSourceGrouped = true;
cvsProjects.ItemsPath = new PropertyPath("Activities");//这里需要指定每组数据子项目的路径
gridView.ItemsSource = cvsProjects.View;
}
private void InitActivities()
{
List Activities = new List();
Activities.Add(new Activity()
{
Name = "Activity 1",
Complete = true,
DueDate = startDate.AddDays(4),
Project = "Project 1"
});
Activities.Add(new Activity()
{
Name = "Activity 2",
Complete = true,
DueDate = startDate.AddDays(5),
Project = "Project 1"
});
Activities.Add(new Activity()
{
Name = "Activity 3",
Complete = false,
DueDate = startDate.AddDays(7),
Project = "Project 1"
});
Activities.Add(new Activity()
{
Name = "Activity 4",
Complete = false,
DueDate = startDate.AddDays(9),
Project = "Project 1"
});
Activities.Add(new Activity()
{
Name = "Activity 5",
Complete = false,
DueDate = startDate.AddDays(14),
Project = "Project 1"
});
Activities.Add(new Activity()
{
Name = "Activity A",
Complete = true,
DueDate = startDate.AddDays(2),
Project = "Project 2"
});
Activities.Add(new Activity()
{
Name = "Activity B",
Complete = false,
DueDate = startDate.AddDays(4),
Project = "Project 2"
});
Activities.Add(new Activity()
{
Name = "Activity C",
Complete = true,
DueDate = startDate.AddDays(5),
Project = "Project 2"
});
Activities.Add(new Activity()
{
Name = "Activity D",
Complete = false,
DueDate = startDate.AddDays(9),
Project = "Project 2"
});
Activities.Add(new Activity()
{
Name = "Activity E",
Complete = false,
DueDate = startDate.AddDays(18),
Project = "Project 2"
});
//自己创建分组 使用Linq查询的分组数据
var result = from act in Activities
group act by act.Project into grp
orderby grp.Key
select grp;
cvsActivities.Source = result;
//return result.ToList();//这个方法不能使用
        }
private List InitProjects()
{
List Projects = new List();
//第一个Project
Project newProject = new Project();
newProject.Name = "Project 1";
newProject.Activities.Add(new Activity() { Name = "Activity 1", Complete = true, DueDate = startDate.AddDays(4) });
newProject.Activities.Add(new Activity() { Name = "Activity 2", Complete = true, DueDate = startDate.AddDays(5) });
newProject.Activities.Add(new Activity() { Name = "Activity 3", Complete = false, DueDate = startDate.AddDays(7) });
newProject.Activities.Add(new Activity() { Name = "Activity 4", Complete = false, DueDate = startDate.AddDays(9) });
newProject.Activities.Add(new Activity() { Name = "Activity 5", Complete = false, DueDate = startDate.AddDays(14) });
Projects.Add(newProject);
//第二个Project
newProject = new Project();
newProject.Name = "Project 2";
newProject.Activities.Add(new Activity() { Name = "Activity A", Complete = true, DueDate = startDate.AddDays(2) });
newProject.Activities.Add(new Activity() { Name = "Activity B", Complete = false, DueDate = startDate.AddDays(3) });
newProject.Activities.Add(new Activity() { Name = "Activity C", Complete = true, DueDate = startDate.AddDays(5) });
newProject.Activities.Add(new Activity() { Name = "Activity D", Complete = false, DueDate = startDate.AddDays(9) });
newProject.Activities.Add(new Activity() { Name = "Activity E", Complete = false, DueDate = startDate.AddDays(18) });
Projects.Add(newProject);
//第三个Project没有子项
newProject = new Project();
newProject.Name = "Project 3";
Projects.Add(newProject);
return Projects;
//这里每一个子项目都包含一个子项集合数据
//cvsProjects.Source = Projects;
//cvsProjects.ItemsPath = new PropertyPath("Activities");
        }
}
public  class Activity
{
public string Name { get; set; }
public DateTime DueDate { get; set; }
public bool Complete { get; set; }
public string Project { get; set; }
}
public  class Project
{
public Project()
{
Activities = new ObservableCollection();
}
public string Name { get; set; }
public ObservableCollection Activities { get; private set; }
}
public class ListGroupStyleSelector : GroupStyleSelector
{
protected override GroupStyle SelectGroupStyleCore(object group, uint level)
{
// Group g = new Group();
return (GroupStyle)App.Current.Resources["listViewGroupStyle"];//(GroupStyle)g.Resources["listViewGroupStyle"]; //(GroupStyle)App.Current.Resources["listViewGroupStyle"];
    }
}
}
　　下面讲解下代码和我遇到的问题：
a、里面有两个类Activity和Project;Activity类主要包括一些基本属性，所以在InitActivities方法里面使用的时Linq查询返回的集合数据，Project类里面还包含一个集合数据;
在InitActivities方法中我本来想直接返回List，但是当我调用ToList方法的时候报错了;貌似在Win8中不能用还是什么，大家指点下;
b、在创建CollectionViewSource的时候主要注意问题的我们必须设置IsSourceGrouped为true、并且必须制定ItemsPath（Linq查询的可以不需要）；在设置数据源的时候我们需要用的是View属性（例： listView.ItemsSource = cvsActivities.View）
　　
第二步：设置GroupStyle






























































　　在XAML页面我们需要设置：
　　GridView.ItemTemplate:每一个组里子项目的样式，相当于没有分组前的每一个Item的模板
GridView.ItemsPanel:每个组的布局方式
GridView.GroupStyle:分组模版样式包括Head和Container
GroupStyle.HeaderTemplate:头模板
GroupStyle.ContainerStyle:每一组的样式
GroupStyle.Panel:每组里面每一个子项的布局方式
在这里遇到问题是：我将ListView的GroupStyleSelector写在当前页面通过当前页面实例去获取资源的时候会产生一个StackOverFlow异常，放在App.xaml页面就不会，请指点下;
运行结果

在运行结果上面为什么会出想默认就选择了第一项;难道是使用了CollectionViewSource的缘故吗？因为我没有设置默认选择,求指点。
详细代码大家可以参考MSDN