各位大师：
在Application 中定义了一个”ObservableCollection<Person>“类型的变量，姑且称为”Companys“，并且在其填充了数据，在Window中有一个”TreeView“类型的控件需要绑定这个”Companys“变量，如何实现呢？
类Application是这样定义的：
public partial class App : Application
{
public ObservableCollection<Company> Companys { get; set; }
public App()
{
this.Companys = new ObservableCollection<Company>();
}
private void Application_Startup(object sender, StartupEventArgs e)
{
//information for Company-1
Company dataCompany1 = new Company() { Name = "北京XX公司", Description = "系统销售商" };
this.Companys.Add(dataCompany1);
Department dataDepartment11 = new Department() { Name = "工程部", Description = "负责施工和售后服务的部门" };
dataCompany1.Departments.Add(dataDepartment11);
dataDepartment11.Persons.Add(new Person() { Name = "张三", Description = "经理" });
dataDepartment11.Persons.Add(new Person() { Name = "李四", Description = "工程师" });
dataDepartment11.Persons.Add(new Person() { Name = "王五", Description = "工程师" });
Department dataDepartment12 = new Department() { Name = "开发部", Description = "负责产品开发的部门" };
dataCompany1.Departments.Add(dataDepartment12);
dataDepartment12.Persons.Add(new Person() { Name = "张三", Description = "经理" });
dataDepartment12.Persons.Add(new Person() { Name = "李四", Description = "工程师" });
dataDepartment12.Persons.Add(new Person() { Name = "王五", Description = "工程师" });
Department dataDepartment13 = new Department() { Name = "产品部", Description = "负责产品整合的部门" };
dataCompany1.Departments.Add(dataDepartment13);
dataDepartment13.Persons.Add(new Person() { Name = "张三", Description = "经理" });
dataDepartment13.Persons.Add(new Person() { Name = "李四", Description = "工程师" });
dataDepartment13.Persons.Add(new Person() { Name = "王五", Description = "工程师" });
//information for Company-2
Company dataCompany2 = new Company() { Name = "北京YY公司", Description = "系统应用整合商" };
this.Companys.Add(dataCompany2);
Department dataDepartment21 = new Department() { Name = "工程部", Description = "负责施工和售后服务的部门" };
dataCompany2.Departments.Add(dataDepartment21);
dataDepartment21.Persons.Add(new Person() { Name = "张三", Description = "经理" });
dataDepartment21.Persons.Add(new Person() { Name = "李四", Description = "工程师" });
dataDepartment21.Persons.Add(new Person() { Name = "王五", Description = "工程师" });
Department dataDepartment22 = new Department() { Name = "开发部", Description = "负责产品开发的部门" };
dataCompany2.Departments.Add(dataDepartment22);
dataDepartment22.Persons.Add(new Person() { Name = "张三", Description = "经理" });
dataDepartment22.Persons.Add(new Person() { Name = "李四", Description = "工程师" });
dataDepartment22.Persons.Add(new Person() { Name = "王五", Description = "工程师" });
Department dataDepartment23 = new Department() { Name = "产品部", Description = "负责产品整合的部门" };
dataCompany2.Departments.Add(dataDepartment23);
dataDepartment23.Persons.Add(new Person() { Name = "张三", Description = "经理" });
dataDepartment23.Persons.Add(new Person() { Name = "李四", Description = "工程师" });
dataDepartment23.Persons.Add(new Person() { Name = "王五", Description = "工程师" });
}
public ObservableCollection<Company> GetCompanys()
{
//return the list for all companys
return this.Companys;
}
}
Window所对应的”XAML“文件是这样定义的：
<Window x:Class="Sample.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:Sample="clr-namespace:Sample"
Title="Window1" Height="500" Width="300" Background="Gray" Loaded="Window_Loaded">
<Grid>
<Grid.Resources>
<ObjectDataProvider x:Key="allCompanys" ObjectInstance="{x:Type Sample:App}" MethodName="GetCompanys"/>
</Grid.Resources>
<Grid.RowDefinitions>
<RowDefinition Height="30"/>
<RowDefinition/>
</Grid.RowDefinitions>
<Label Grid.Row="0" Margin="2" Content="示范数据:" VerticalContentAlignment="Bottom"/>
<TreeView Grid.Row="1" Name="tvCompany" Margin="2" Background="DarkBlue" ItemsSource="{Binding Source={StaticResource allCompanys}}">
<TreeView.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Departments}">
<TextBlock Text="{Binding Path=Name}"/>
<HierarchicalDataTemplate.ItemTemplate>
<HierarchicalDataTemplate ItemsSource="{Binding Path=Persons}">
<TextBlock Text="{Binding Path=Name}"/>
<HierarchicalDataTemplate.ItemTemplate>
<DataTemplate>
<TextBlock Text="{Binding Path=Name}"/>
</DataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</HierarchicalDataTemplate.ItemTemplate>
</HierarchicalDataTemplate>
</TreeView.ItemTemplate>
</TreeView>
</Grid>
</Window>
在上面的代码中，类Company, Department以及Person都是彼此嵌套的关系，每个类中只有两个变量，即"Name"和”Description“。
但是结果就是不对，在TreeView中没有任何数据显示。
是什么地方不对呢？渴望那位大仙给指点一下，郁闷死了！
先谢了。
一派胡言
如何将TreeView绑定到“Application”中的一个“ObservableCollection<> “类型变量中？
