I have a ListBox with various rows of data (items that someone is buying, basically), and when the user clicks on a row it populates a textbox on the side with the quantity of how many of that thing he's buying. For example, one row might be "Pencils, $5, 3" and clicking the row makes "3" appear in the textbox.
If the user changes that 3 to a 7, for example, I want that to be put back into the row, so we now have "Pencils, $5, 7"
How do I do that?
You need to program the Listbox's SelectedIndexChanged event and the Textbox's TextChanged event. Here's your snippet:
Private Sub ListBox1_SelectedIndexChanged( _
ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles ListBox1.SelectedIndexChanged
// Exit if no item is selected
If ListBox1.SelectedItem Is Nothing Then Exit Sub
// Get the item's text
Dim item As String = ListBox1.SelectedItem.ToString
// Keep only the last part
item = item.Substring(item.LastIndexOf(", ") + 2)
// Update the textbox
TextBox1.Text = item
End Sub
Private Sub TextBox1_TextChanged( _
ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles TextBox1.TextChanged
// Exit if no item is selected
If ListBox1.SelectedItem Is Nothing Then Exit Sub
// Get the item's text, removing the last part
Dim item As String = ListBox1.SelectedItem.ToString
item = item.Substring(0, item.LastIndexOf(", ") + 2)
// Add the numerical value of the textbox's text
item &= Val(TextBox1.Text)
// Get the index of the selected item
Dim index As Integer = ListBox1.SelectedIndex
// Remove the old item, add the new one and select it
ListBox1.Items.RemoveAt(index)
ListBox1.Items.Insert(index, item)
ListBox1.SelectedIndex = index
End Sub
