SelectedItem 不會綁定到屬性

Question

我有以下組合框：

    <ComboBox
      ItemsSource="{  Binding RclTypes }"
      DisplayMemberPath = "Key" SelectedValuePath = "Value"
      SelectedItem="{ Binding RclTypeSelected, Mode=TwoWay }"/>

我關聯的 ViewModel 文件：

    private Dictionary<string, ProjectDto> _rclTypes;

    public Dictionary<string, ProjectDto> RclTypes
    {
        get => _rclTypes;
        set => SetProperty(ref _rclTypes, value);
    }

    private ProjectDto _rclTypeSelected;

    public ProjectDto RclTypeSelected
    {
        get => _rclTypeSelected;
        set => SetProperty(ref _rclTypeSelected, value);
    }
    public myConstructor()
    {
        PopulateRclTypes();
    }

    public void PopulateRclTypes()
    {
       _rclTypes = new Dictionary<string, ProjectDto>();

            foreach (ProjectDto runType in Enum.GetValues(typeof(ProjectDto)))
            {
                string firstThreeLettersOfRunTypeName = runType.ToString().Substring(0, 3);

                if (firstThreeLettersOfRunTypeName == "Rcl" && runType.ToString().Length > 3)
                {
                    string displayRunTypeName = runType.ToString().Substring(3, runType.ToString().Length - 3);
                    _rclTypes.Add(displayRunTypeName, runType);
                }
             }
      }
        

ComboBox 下拉列表被正確填充，但 RclTypeSelected 屬性沒有填充正確的對象並且始終為空。 為什么以及如何糾正？

Answer 1

SelectedValuePath旨在與SelectedValue結合使用，而不是SelectedItem ：

<ComboBox ItemsSource="{Binding RclTypes}"
          DisplayMemberPath="Key"
          SelectedValuePath="Value"
          SelectedValue="{Binding RclTypeSelected}"/>