将对象属性绑定到组合框

Question

我正在尝试为Combobox 添加绑定class property。该属性是一个枚举。我设法将项目从enum 加载到Combobox 可能有点不正统，但它的工作原理。 （也欢迎改进建议）然后当表单加载时Combobox 显示活动性别，所有选项都在下拉菜单中。

但是当我将 Combobox 的焦点更改为 button 以测试结果时，它会恢复为男性（在我的测试中，我想将性别更改为女性）。

如何确保将新的性别值传递给我的对象？

这是我的代码示例

Public Class Form1

    Private Personobject As Person

    Public Sub New()
        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        Personobject = New Person
        Personobject.Gender = GenderEnum.Male

        Dim enumType As Type = GetType(GenderEnum)
        Dim names() As String = [Enum].GetNames(enumType)

        For Each s As String In names
            ComboBox1.Items.Add(s)
        Next

        ComboBox1.DataBindings.Add("Text", Personobject, "Gender")
    End Sub

    Private Enum GenderEnum
        Male
        Female
    End Enum

    Private Class Person
        Public Property Gender As GenderEnum
    End Class

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Debug.Print(Personobject.Gender.ToString)
    End Sub
End Class

Answer 1

如果您使用数据绑定，则使用ComboBox.DataSource 绑定项目集合以供选择，并使用ComboBox.SelectedValue 作为选定值

Public Class Form1

    Private _Person As Person

    Public Sub New()
        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.

        ' Bound list of enums to the combobox

        Dim genderList As List(Of GenderEnum) = [Enum].GetValues(GetType(GenderEnum))
                                                  .OfType(Of GenderEnum)
                                                  .ToList()
        ComboBox1.DataSource = genderList

        _Person = New Person With { .Gender = GenderEnum.Male }

        // Bound Person.Gender to the ComboBox.SelectedValue
        ComboBox1.DataBindings.Add("SelectedValue", _Person, NameOf(_Person.Gender), True)

    End Sub

    Private Enum GenderEnum
        Male
        Female
    End Enum

    Private Class Person
        Public Property Gender As GenderEnum
    End Class

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Debug.Print(Personobject.Gender.ToString)
    End Sub
End Class

请注意，如果您希望在其他地方更新_person.Gender 时更改组合框选定的值，则Person 类需要实现INotifyPropertyChanged 接口并在Gender 属性的设置器中引发PropertyChanged 事件。