我有两个简单的Model类和一个ViewModel...
public class GridItem
{
public string Name { get; set; }
public int CompanyID { get; set; }
}
public class CompanyItem
{
public int ID { get; set; }
public string Name { get; set; }
}
public class ViewModel
{
public ViewModel()
{
GridItems = new ObservableCollection<GridItem>() {
new GridItem() { Name = "Jim", CompanyID = 1 } };
CompanyItems = new ObservableCollection<CompanyItem>() {
new CompanyItem() { ID = 1, Name = "Company 1" },
new CompanyItem() { ID = 2, Name = "Company 2" } };
}
public ObservableCollection<GridItem> GridItems { get; set; }
public ObservableCollection<CompanyItem> CompanyItems { get; set; }
}
...以及一个简单的窗口:
<Window x:Class="DataGridComboBoxColumnApp.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="350" Width="525">
<Grid>
<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding GridItems}" >
<DataGrid.Columns>
<DataGridTextColumn Binding="{Binding Name}" />
<DataGridComboBoxColumn ItemsSource="{Binding CompanyItems}"
DisplayMemberPath="Name"
SelectedValuePath="ID"
SelectedValueBinding="{Binding CompanyID}" />
</DataGrid.Columns>
</DataGrid>
</Grid>
</Window>
在App.xaml.cs中,将ViewModel设置为MainWindow的DataContext
:
public partial class App : Application
{
protected override void OnStartup(StartupEventArgs e)
{
base.OnStartup(e);
MainWindow window = new MainWindow();
ViewModel viewModel = new ViewModel();
window.DataContext = viewModel;
window.Show();
}
}
如您所见,我将DataGrid的ItemsSource
设置为ViewModel的GridItems
集合。 这部分是有效的,单个名称为"Jim"的网格行列被显示出来。
我还想将每一行中ComboBox的ItemsSource
设置为ViewModel的CompanyItems
集合,但这部分不起作用:ComboBox仍然为空,并且在调试器输出窗口中我看到了一个错误消息:
System.Windows.Data Error: 2 : Cannot find governing FrameworkElement or FrameworkContentElement for target element. BindingExpression:Path=CompanyItems; DataItem=null; target element is 'DataGridComboBoxColumn' (HashCode=28633162); target property is 'ItemsSource' (type 'IEnumerable')
我认为WPF希望CompanyItems
是GridItem
的属性,但实际上并非如此,这就是绑定失败的原因。
我已经尝试使用RelativeSource
和AncestorType
进行工作,如下所示:
<DataGridComboBoxColumn ItemsSource="{Binding CompanyItems,
RelativeSource={RelativeSource Mode=FindAncestor,
AncestorType={x:Type Window}}}"
DisplayMemberPath="Name"
SelectedValuePath="ID"
SelectedValueBinding="{Binding CompanyID}" />
但这会在调试器输出中给我另一个错误:
System.Windows.Data Error: 4 : 找不到绑定的源,引用为'RelativeSource FindAncestor, AncestorType='System.Windows.Window', AncestorLevel='1''。 BindingExpression:Path=CompanyItems; DataItem=null; target element is 'DataGridComboBoxColumn' (HashCode=1150788); target property is 'ItemsSource' (type 'IEnumerable')
问题:如何将DataGridComboBoxColumn的ItemsSource绑定到ViewModel的CompanyItems集合?是否可能?
提前感谢您的帮助!