vb：如何一次选择一个列表框中的多个项目？

Question

I have a Listbox with a list of numbers from 1 to 10. Now I want to program to select those numbers greater than 5. But I also want to trigger the SelectedIndexChanged event only once.

I know I can add multiple items into Listbox at once by using addrange() method.

But it seems there isn't a similar solution for select multiple item at once ?

How can i do this ?

Answer 1

youre question is a litle unclear but ...

First you need to set your Listbox SelectionMode to MultySimple.

Then you use ListBox1.SelectedItems.Count < 2 So it trigger the SelectedIndexChanged event only once at the start of the selecting.
Of course you can edit the code to fit your needs and let it trigger whenever you want.

 Private Sub ListBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ListBox1.SelectedIndexChanged
    If ListBox1.SelectedItems.Count < 2 Then
        MsgBox("one")
    End If
End Sub

And to select everything above 5 you need to make a list of integers.
Then use a for each loop to get the items in the list of integers with the values you want.

Then use the list of integers in a for loop to select the items in the listbox.

Dim l As New List(Of Integer)

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    For Each Item As Integer In ListBox1.Items
        If Item > 5 Then
            l.Add(ListBox1.FindString(Item))
        End If
    Next

    For SetItem As Integer = 0 To l.Count - 1
        For i = 0 To ListBox1.Items.Count - 1
            If i = l.Item(SetItem) Then
                ListBox1.SetSelected(i, True)
                Exit For
            End If
        Next
    Next
End Sub