WinForm：從列表框中的選定項目獲取值

Question

如何獲取列表框中所有選定項目的值（不顯示文本）？

我的意圖是使用值（它代表我的數據庫中的主鍵和外鍵）組裝sql查詢。

規格：使用的WinForm有一個.NET Framework 4節

Answer 1

您也可以使用您在列表框中喜歡的任何對象。下面的小例子，但要測試你必須創建一個帶有ListBox和按鈕的表單。 與字典相同的想法，但這將適用於更復雜的對象。

Public Class Form1 

    Dim tests As New List(Of Test) 

    Class Test 
     Private _Key As Integer 
     Public Property Key() As Integer 
      Get 
       Return _Key 
      End Get 
      Set(ByVal value As Integer) 
       _Key = value 
      End Set 
     End Property 


     Private _value As String 
     Public Property Value() As String 
      Get 
       Return _value 
      End Get 
      Set(ByVal value As String) 
       _value = value 
      End Set 
     End Property 
    End Class 

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load 

     With tests 
      .Add(New Test With {.Key = 1, .Value = "Val1"}) 
      .Add(New Test With {.Key = 2, .Value = "Val2"}) 
      .Add(New Test With {.Key = 3, .Value = "Val3"}) 
     End With 

     ListBox1.SelectionMode = SelectionMode.MultiSimple 
     ListBox1.DisplayMember = "Value" 

     For Each t In tests 
      ListBox1.Items.Add(t) 
     Next 

    End Sub 

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click 
     For Each t As Test In ListBox1.SelectedItems 
      Debug.WriteLine(t.Key) 
     Next 
    End Sub 

End Class