vb.net 在 SelectedIndexChanged 上从 Listview 检索项目
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vb.net retrieve items from Listview on SelectedIndexChanged
提问by user1532468
I am trying to get the value from a listview in vb.net, but keep getting an error of:
我试图从 vb.net 中的列表视图中获取值，但不断收到以下错误：
'SelectedItem' is not a member of 'System.Windows.Forms.ListView'.
“SelectedItem”不是“System.Windows.Forms.ListView”的成员。
I think I need to change eventargs to some other event type, but am struggling with this. Could someone please point out my error. Thanks
我想我需要将 eventargs 更改为其他一些事件类型，但我正在为此苦苦挣扎。有人可以指出我的错误。谢谢
Sub filllistview()
Try
'creatconn()
cn.Open()
Dim cmd As OleDbCommand = New OleDbCommand("Select * from Customers", cn)
dr = cmd.ExecuteReader()
While dr.Read()
ListView1.Items.Add(dr(0).ToString())
ListView1.Items(ListView1.Items.Count - 1).SubItems.Add(dr(1))
End While
Catch ex As Exception
System.Windows.Forms.MessageBox.Show(ex.Message)
Finally
dr.Close()
cn.Close()
End Try
End Sub
Need to catch here
需要抓住这里
Private Sub ListView1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As EventArgs) Handles ListView1.SelectedIndexChanged
Try
showcontectsinlistview()
str = ListView1.SelectedItem **<--- ERROR**
Catch ex As Exception
MessageBox.Show(ex.Message)
End Try
End Sub
回答by Stefano Bafaro
This is true beacuse it doesn't exist a "SelectedItem" property.
The ListView object has a property "SelectedItems", that is a collection. So you could use something like: listView1.SelectedItems[0].
这是真的，因为它不存在“SelectedItem”属性。ListView 对象有一个属性“SelectedItems”，即一个集合。所以你可以使用类似的东西：listView1.SelectedItems[0].
With this you will have the first of the selected items in the collection given by the "SelectedItems" property. To navigate through all the selected items, you can loop between them in this way:
有了这个，您将拥有“SelectedItems”属性给出的集合中的第一个选定项目。要浏览所有选定的项目，您可以通过以下方式在它们之间循环：
For Each itm As ListViewItem In ListView1.SelectedItems
If itm.Selected Then
For i As Integer = 0 To itm.SubItems.Count - 1
str += itm.SubItems(i).Text
Next
End If
Next
In this way you build a string with all the values of all the selected items. If you have only 1 selected item in the listview, you will have only that value.
通过这种方式，您可以使用所有选定项目的所有值构建一个字符串。如果您在列表视图中只有 1 个选定项目，则您将只有该值。
回答by user2125649
Look at this example
看这个例子
Private Sub lstDirectoryInfo_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles lstDirectoryInfo.SelectedIndexChanged
Dim str As String = String.Empty
For Each itm As ListViewItem In lstDirectoryInfo.SelectedItems
If itm.Selected Then
For i As Integer = 0 To itm.SubItems.Count - 1
str = itm.SubItems(i).Text
Next
End If
Next
MessageBox.Show(str)
End Sub
