绑定不更改组合框的选定值

Question

我有ComboBox

  <ComboBox Height="23" Name="DriveSelection" Width="120"
                              ItemsSource="{Binding Path=FixedDrives}"
                              DisplayMemberPath="Name"
                              SelectedItem="{Binding DriveSelection_SelectionChanged }"
                              IsSynchronizedWithCurrentItem="True"
                              IsEnabled="{Binding DriveIsEnabled}"
                              />

在我的viewModel它看起来像这样：

    public PathSelectionPageViewModel(PathSelectionPage _page)
    {
        this.page = _page;
        this.root = Path.GetPathRoot(App.Instance.PathManager.InstallRoot).ToUpperInvariant();
        this.DriveSelection = this.root;
        this.DriveSelection_SelectionChanged = new DriveInfo(this.root);
        this.DriveIsEnabled = App.Instance.PathManager.CanModify;
        this.RunText = App.Instance.InstallationProperties.InstallationScript.Installer.Name;

    }
public ObservableCollection<DriveInfo> FixedDrives
{
     get
        {
            if (this.fixedDrives != null)
                return this.fixedDrives;
            this.fixedDrives = new ObservableCollection<DriveInfo>(Enumerable.Where<DriveInfo>((IEnumerable<DriveInfo>)DriveInfo.GetDrives(), (Func<DriveInfo, bool>)(driveInfo => driveInfo.DriveType == DriveType.Fixed)));
            return this.fixedDrives;
        }
    }

     public DriveInfo DriveSelection_SelectionChanged
    {
        get
        {
           return this.driveSelection;
        }
        set
        {
            if (value == this.driveSelection)
                return;
            this.driveSelection = value;
            UpdatePathManager();
            this.OnPropertyChanged("DriveSelection_SelectionChanged");
        }
    }

如您所见，我将hardrives列表作为itemSource绑定到组合框。 然后，如果需要，我将在此行中更改所选项目：

this.DriveSelection_SelectionChanged = new DriveInfo(this.root);

例如。 this.root指向驱动器E因此组合框选择应更改为E，但现在它仍挂在C 。 我的绑定错误或其他地方有错误？

Answer 1

您在这一行用new创建的对象

this.DriveSelection_SelectionChanged = new DriveInfo(this.root);

数据绑定到ItemsSource的FixedDrivers列表中未包含。 如果您选择了FixedDrivers中的一项，则将选择正确的项

var selectedItem = this.FixedDrives.FirstOrDefault(d => d.Name == this.Root);
this.DriveSelection_SelectionChanged = selectedItem;