从 CheckedListBox VB.NET Winform 中检索选中的项目

Retrieved the checked items from a CheckedListBox VB.NET Winform

提问by user2103670

I asked this question before but suggested to provide a more details. Here is the problem:

我之前问过这个问题，但建议提供更多细节。这是问题所在：

1. I have a CheckedListBox called CheckedList_Facility. All items in this CheckedList_Facilityare getting from SQL Server Datasource. All items are loaded properly using the below code

   Dim queryString As String = "SELECT Facility FROM Database.dbo.Facility "
   Dim connection As New SqlConnection(connectionString)
   Dim command As New SqlCommand(queryString, connection)
   connection.Open()
   Dim dataReader As SqlDataReader = command.ExecuteReader()
   Dim source As New BindingSource
   source.DataSource = dataReader
   CheckedList_Facility.DataSource = source
   CheckedList_Facility.ValueMember = "Facility"
   connection.Close()
   

2. I would like to get a list of items that are checked. For example,

   [X] AAA

   [X] BBB

   [ ] CCC

   [ ] DDD

   [X] EEE

1. 我有一个名为的 CheckedListBox CheckedList_Facility。此中的所有项目CheckedList_Facility均来自 SQL Server 数据源。使用以下代码正确加载所有项目

   Dim queryString As String = "SELECT Facility FROM Database.dbo.Facility "
   Dim connection As New SqlConnection(connectionString)
   Dim command As New SqlCommand(queryString, connection)
   connection.Open()
   Dim dataReader As SqlDataReader = command.ExecuteReader()
   Dim source As New BindingSource
   source.DataSource = dataReader
   CheckedList_Facility.DataSource = source
   CheckedList_Facility.ValueMember = "Facility"
   connection.Close()
   

2. 我想获得已检查项目的列表。例如，

   [X] AAA

   [X] BBB

   [ ] CCC

   [ ] 滴滴

   [X] 电子电气设备

then the list should be "AAA", "BBB", "EEE"

那么列表应该是“AAA”、“BBB”、“EEE”

1. To test if the item is retrieved correctly, I using a button call bt_GetItemand when this button is pressed, a msgbox displays the items that are checked. With this code:

   Dim itemChecked As Object
   For Each itemChecked In CheckedList_Facility.CheckedItems
       MsgBox(itemChecked.ToString)
   Next
   

2. However, I only receive this error message

   System.Data.Common.DataRecordInternal

1. 为了测试项目是否被正确检索，我使用了一个按钮调用bt_GetItem，当这个按钮被按下时，一个 msgbox 显示被检查的项目。使用此代码：

   Dim itemChecked As Object
   For Each itemChecked In CheckedList_Facility.CheckedItems
       MsgBox(itemChecked.ToString)
   Next
   

2. 但是，我只收到此错误消息

   System.Data.Common.DataRecordInternal

Technically, this might not be an error but instead of receiving "AAA", I get this

从技术上讲，这可能不是错误，但我没有收到“AAA”，而是收到了这个

System.Data.Common.DataRecordInternal

回答by Winks

Because you bound the checkedlistbox to your datareader, the checked object internally is actually a {System.Data.Common.DataRecordInternal}and not a string or any other native object. You have to access the itemproperty within the object to get to the string you want, like so:

因为您将checkedlistbox 绑定到您的datareader，所以内部的checked 对象实际上是a{System.Data.Common.DataRecordInternal}而不是字符串或任何其他本机对象。您必须访问item对象内的属性才能获得所需的字符串，如下所示：

 MsgBox(itemChecked.item("Facility").ToString)

回答by Alex

In order for your "AAA" (type of string) to be displayed you must access the itemCheckedobject's property. Since you're selecting "Facility" we'll use that. The message you were receiving (System.Data.Common.DataRecordInternal) was the object itemCheckedtype.

为了显示您的“AAA”（字符串类型），您必须访问itemChecked对象的属性。由于您选择了“设施”，我们将使用它。您收到的消息（System.Data.Common.DataRecordInternal）是对象itemChecked类型。

MsgBox(itemChecked.Items("Facility").ToString)

Should output "AAA"

应该输出“AAA”

回答by Mateus Campos

For i As Integer = 0 To lbSit.Items.Count - 1
    If CType(lbSit.Items(i), DataRowView)(lbSit.ValueMember).ToString = "32" Then
        lbSit.SetItemChecked(i, True)
    End If
Next

回答by 15464

Private Sub WhatIsChecked_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles WhatIsChecked.Click
    ' Display in a message box all the items that are checked.
    Dim indexChecked As Integer
    Dim itemChecked As Object
    Const quote As String = """"

    ' First show the index and check state of all selected items.
    For Each indexChecked In CheckedListBox1.CheckedIndices
        ' The indexChecked variable contains the index of the item.
        MessageBox.Show("Index#: " + indexChecked.ToString() + ", is checked. Checked state is:" + _
                        CheckedListBox1.GetItemCheckState(indexChecked).ToString() + ".")
    Next

    ' Next show the object title and check state for each item selected.
    For Each itemChecked In CheckedListBox1.CheckedItems

        ' Use the IndexOf method to get the index of an item.
        MessageBox.Show("Item with title: " + quote + itemChecked.ToString() + quote + _
                        ", is checked. Checked state is: " + _
                        CheckedListBox1.GetItemCheckState(CheckedListBox1.Items.IndexOf(itemChecked)).ToString() + ".")
    Next