[vb.net] Removing items from a ListBox in VB.net

I have two ListBox1 and ListBox2. I have inserted items into a ListBox2 with the following code by selecting ListBox1 item:

da6 = New SqlDataAdapter("select distinct(component_type) from component where   component_name='" & ListBox1.SelectedItem() & "'", con)
da6.Fill(ds6, "component")
For Each row As DataRow In ds6.Tables(0).Rows
    ListBox2.Items.Add(row.Field(Of String)("component_type"))
Next

But when I reselect another item of ListBox1 then ListBox2 shows preloaded items and now loaded item together. I want only now loaded item to be displayed in listbox. I used this code but problem not solved:

For i =0 To ListBox2.items.count - 1
    ListBox2.Items.removeAt(i)
Next

OR listbox2.items.clear() is also not working..

How can I clear all items in the ListBox2?

Already tested by me, it works fine

For i =0 To ListBox2.items.count - 1
ListBox2.Items.removeAt(0)
Next

There is a simple method for deleting selected items, and all these people are going for a hard method:

lstYOURVARIABLE.Items.Remove(lstYOURVARIABLE.SelectedItem)

I used this in Visual Basic mode on Visual Studio.

This worked for me.

Private Sub listbox_MouseDoubleClick(sender As Object, e As MouseEventArgs) 
        Handles listbox.MouseDoubleClick
        listbox.Items.RemoveAt(listbox.SelectedIndex.ToString())
    End Sub

   Dim ca As Integer = ListBox1.Items.Count().ToString
    While Not ca = 0
        ca = ca - 1
        ListBox1.Items.RemoveAt(ca)
    End While

Use simply:

ListBox2.Items.Clear()

• To take your last edit into account: Do that before you add the new items

MSDN: ListBox.ObjectCollection.Clear

Removes all items from the collection.

Note that the problem with your approach is that RemoveAt changes the index of all remaining items.

When you remove an item from the list, the indexes change for subsequent items in the list. All information about the removed item is deleted. You can use this method to remove a specific item from the list by specifying the index of the item to remove from the list. To specify the item to remove instead of the index to the item, use the Remove method. To remove all items from the list, use the Clear method.

If you want to use RemoveAt anyway, you can go backwards, for example with:

a for-loop:

For i As Int32 = ListBox2.Items.Count To 0 Step -1
    ListBox2.Items.RemoveAt(i)
Next

or a while

While ListBox2.Items.Count > 0
    ListBox2.Items.RemoveAt(ListBox2.Items.Count - 1)
End While

old C# code

for (int i = ListBox2.Items.Count - 1; i >= 0; i--)
    ListBox2.Items.RemoveAt(i);

while(ListBox2.Items.Count > 0)
    ListBox2.Items.RemoveAt(ListBox2.Items.Count - 1);

This code worked for me:

ListBox1.Items.RemoveAt(ListBox1.SelectedIndex)

If you only want to clear the list box, you should use the Clear (winforms | wpf | asp.net) method:

ListBox2.Items.Clear()

Here's the code I came up with to remove items selected by a user from a listbox It seems to work ok in a multiselect listbox (selectionmode prop is set to multiextended).:

Private Sub cmdRemoveList_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmdRemoveList.Click
    Dim knt As Integer = lstwhatever.SelectedIndices.Count
    Dim i As Integer
    For i = 0 To knt - 1
        lstwhatever.Items.RemoveAt(lstwhatever.SelectedIndex)
    Next
End Sub

I think your ListBox already clear with ListBox2.Items.Clear(). The problem is that you also need to clear your dataset from previous results with ds6.Tables.Clear().

Add this in your code:

da6 = New SqlDataAdapter("select distinct(component_type) from component where   component_name='" & ListBox1.SelectedItem() & "'", con)
    ListBox1.Items.Clear()    ' clears ListBox1
    ListBox2.Items.Clear()    ' clears ListBox2
    ds6.Tables.Clear()        ' clears DataSet  <======= DON'T FORGET TO DO THIS
da6.Fill(ds6, "component")
For Each row As DataRow In ds6.Tables(0).Rows
    ListBox2.Items.Add(row.Field(Of String)("component_type"))
Next