title: Increment character in a string
body: <p>I have a 2 character string composed only of the 26 capital alphabet letters, <code>'A'</code> through <code>'Z'</code>.</p>
  
  <p>We have a way of knowing the "highest" used value (e..g <code>"IJ"</code> in <code>{"AB", "AC", "DD", "IH", "IJ"}</code>). We'd like to get the "next" value (<code>"IK"</code> if <code>"IJ"</code> is the "highest").</p>
  
  <pre><code>Function GetNextValue(input As String) As String
    Dim first = input(0)
    Dim last = input(1)
    If last = "Z"c Then
      If first = "Z"c Then Return Nothing
  
      last = "A"c
      first++
    Else
      last++
    EndIf
  
    Return first &amp; last
  End Function
  </code></pre>
  
  <p>Obviously <code>char++</code> is not valid syntax in VB.NET. C# <a href="https://stackoverflow.com/a/12838589/945456">apparently</a> allows you to do this. Is there something <strike>shorter</strike> less ugly than this that'd increment a letter? (Note: <code>Option Strict</code> is on)</p>
  
  <pre><code>CChar(CInt(char)+1).ToString
  </code></pre>
  
  <p><strong>Edit</strong>: As noted in comment/answers, the above line won't even compile. You can't convert from Char -> Integer at all in VB.NET.</p>