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[英]Binding to TreeView SelectedItem works as ItemsSource but not for custom DependencyProperty
[英]ItemsSource to property of SelectedItem of TreeView
我正在創建我的第一個WPF應用程序(之前已經使用WinForms完成了一些操作),並且我開始喜歡它(即使它有時增加了不必要的復雜性。)。 但是我遇到了一個我無法真正解決的問題。
問題:我有一個TreeView和一個伴隨的GroupBox,具有選定(第二級)項目的屬性。 這些屬性在TextBoxes中可編輯(綁定到SelectedItem。[Property]),並且可以正常工作。 但是屬性之一是一個列表(定義為ObservableCollection),我想在ComboBox中顯示它,因此我將ItemsSource綁定到TreeView的SelectedItem.Modes:
<ComboBox Name="FixtureModesListBox" ItemsSource="{Binding ElementName=FixturesTreeView, Path=SelectedItem.Modes}" ItemTemplate="{StaticResource FixtureModeTemplate}" />
這顯然是行不通的,我得到的錯誤是這樣說的:
BindingExpression path error: 'Modes' property not found on 'object' ''efcFixtureModel' ...
該屬性確實存在,已設置,已公開等。
我當前的解決方案可以通過使用一些代碼隱藏(並引用完全相同的“路徑”)使其工作:
private void FixturesTreeView_SelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
{
if (FixturesTreeView.SelectedItem is efcFixtureModel) // The 1st level/parent items is of a different type
{
FixtureModesListBox.ItemsSource = (FixturesTreeView.SelectedItem as efcFixtureModel).Modes;
}
}
我無法解決為什么此方法不起作用的問題,也無法在網上找到任何好的信息。
編輯以包括更多信息:
<TreeView Name="FixturesTreeView" ItemTemplate="{StaticResource FixtureItemTemplate}" SelectedItemChanged="FixturesTreeView_SelectedItemChanged">
</TreeView>
...
// Assignment of ItemsSource
FixturesTreeView.ItemsSource = mainWin.Companies;
...
public partial class efcMainWindow : Window
{
// Definition of Companies
public ObservableCollection<efcCompany> Companies;
...
// Definition of efcCompany
public class efcCompany
{
public int Id { get; set; }
public string Name { get; set; }
public string Url { get; set; }
public string Logo { get; set; }
public int FixtureCount { get { return Fixtures.Count; } }
public ObservableCollection<efcFixtureModel> Fixtures { get; set; }
public efcCompany(string name = "", int id = -1, string url = "", string logo = "")
{
this.Name = name;
this.Id = id;
this.Url = url;
this.Logo = logo;
this.Fixtures = new ObservableCollection<efcFixtureModel>();
}
public override string ToString()
{
return "#" + Id.ToString() + ": " + Name + " (" + Url + ", " + Logo + ")";
}
}
// Definition of efcFixtureController
public class efcFixtureModel
{
public int Id { get; set; }
public int Manufacturer { get; set; }
public efcFixtureType Type { get; set; }
public string Name { get; set; }
public string Image { get; set; }
public string Description { get; set; }
public byte TotalChannelCount { get; set; }
public ObservableCollection<efcFixtureMode> Modes;
public efcFixtureModel()
{
Modes = new ObservableCollection<efcFixtureMode>();
}
public override string ToString()
{
return "#" + Id.ToString() + ": " + Name + " (" + Type.ToString() + ", " + Image + ", " + Description + ")";
}
}
您需要將efcFixtureModel.Modes從Field轉換為Property:
public ObservableCollection<efcFixtureMode> Modes { get; set; }
如前所述,您需要將FixturesTreeView中的SelectedItem綁定到ViewModel中類型為efcFixtureModel的屬性。
<TreeView Name="FixturesTreeView" ItemTemplate="{StaticResource FixtureItemTemplate}" SelectedItemChanged="FixturesTreeView_SelectedItemChanged"
SelectedItem="{Binding TreeViewSelectedItem}">
</TreeView>
<ComboBox Name="FixtureModesListBox" ItemsSource="{Binding TreeViewSelectedItem.Modes}" ItemTemplate="{StaticResource FixtureModeTemplate}" />
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