Is there an alternative method to using 15 If statements? - vb.net

Question

I have 15 items in my ComboBox and when the user selects an item I want to present something different in my TextBox.
At the moment I have:
If cb_dropdown.SelectedIndex = 0 Then
RTB_Sql.Text = "update access
set accessdesc = 'Less than 5' where accessID < '5'"
Else
If cb_dropdown.SelectedIndex = 1 Then
RTB_Sql.Text = "update access
set accessdesc = 'More than 5' where accessID > '5' and < '10' "
Else
If cb_dropdown.SelectedIndex = 2 Then
RTB_Sql.Text = ""
etc....
Is there a nicer and more methodical way to approach this as it looks quite scruffy?

Answer 1

Yes, it is called select.
Select Case cb_dropdown.SelectedIndex
Case 0 To 4
RTB_Sql.Text = "update access
set accessdesc = 'Less than 5' where accessID < '5'"
Case 5
RTB_Sql.Text = [...]
Case Else
RTB_Sql.Text = [...]
End Case
Although in your case I think what you are looking for is < (less than) and > (greater than).
If cb_dropdown.SelectedIndex < 5 Then
RTB_Sql.Text = "update access set accessdesc = 'Less than 5' where accessID < '5'"
ElseIf cb_dropdown.SelectedIndex < 10 Then
RTB_Sql.Text = "update access set accessdesc = 'More than 5' where accessID > '5' and < '10' "
End If
Not really sure what you are trying to do though. Maybe if you explain in more detail someone can provide a better answer. So let me take a wild guess:
Dim n As Integer = cb_dropdown.SelectedIndex * 5
RTB_Sql.Text = "update access set accessdesc = 'More than " + n + "' where accessID > '" + n + "' and < '" + (n+6) + "' "
This will give you the following result based on SelectedIndex:
0 = from 1 to including 5
1 = from 6 to including 10
etc...
If you want to shift it down one (include 0 and not 5 in first batch) then just change > to >= and 6 to 5.

Answer 2

You can also use something like this if you want to check range of values:
Sub Main()
Dim i As Integer = 6
Select Case True
Case 0 <= i AndAlso i < 5
Console.WriteLine("i is between 0 and 4")
Case 6 <= i
Console.WriteLine("i is 6 or greater")
End Select
Console.ReadLine()
End Sub
Be aware that it stops in the first true condition.