How can you detect key presses in vb console mode? - vb.net

Question

I wanted to make a program involving a menu at the start but instead of using the typical select case I wanted to do it differently.
I wanted it to give the user some options and then they would use the arrow keys to move a little arrow next to the options.
Finally you press enter and then you would advance to the next screen that you selected. I have been searching the web but I could only find this kind of stuff in form mode, not console. If this isn't possible let me know and I would appreciate any feedback.

Answer 1

One simple way is with a menu class that will print out the menu and highlight the item number passed to it:
Class Menu
Private MenuList As New List(Of String)
Public ReadOnly Property LineCount As Integer
Get
Return MenuList.Count
End Get
End Property
Public Sub CreateNewMenu(strings As IEnumerable(Of String))
MenuList.Clear()
For Each s In strings
MenuList.Add(s)
Next
End Sub
Public Sub PrintMenu(highlight As Integer)
If highlight < 0 OrElse highlight > MenuList.Count - 1 Then
Throw New Exception("Invalid menu index")
End If
For I = 0 To MenuList.Count - 1
If I = highlight Then
SwapColors()
Console.WriteLine(MenuList(I))
Console.ResetColor()
Else
Console.WriteLine(MenuList(I))
End If
Next
End Sub
Private Sub SwapColors()
Dim temp = Console.BackgroundColor
Console.BackgroundColor = Console.ForegroundColor
Console.ForegroundColor = temp
End Sub
End Class
To use it would look like this:
Dim MainMenu As New Menu
MainMenu.CreateNewMenu(
{
"Option A",
"Option B",
"Option C"
})
Dim CurrentItem As Integer = 0
Dim CurrentKey As ConsoleKey
While CurrentKey <> ConsoleKey.Enter
Console.Clear()
MainMenu.PrintMenu(CurrentItem)
CurrentKey = Console.ReadKey(True).Key
If CurrentKey = ConsoleKey.UpArrow Then
CurrentItem -= 1
ElseIf CurrentKey = ConsoleKey.DownArrow Then
CurrentItem += 1
End If
CurrentItem = (CurrentItem + MainMenu.LineCount) Mod MainMenu.LineCount
End While
This will use inverted colors to highlight the selected item, but this can easily be changed to add an indicator when writing the item to the console, if desired.
When the while loop exits CurrentItem will hold the 0-based index of the selected menu item.
One advantage of this approach is that you can have several collections of menus that will allow you to show specific ones based on the selection.