title: Conversion from string "a" to type 'Boolean' is not valid
body: <p>This one's really got me confused. I'm trying to do a visual basic console application that if the user enters 'A' or 'a' then the program should do 'x', but that's not working. The error I get is:</p>
  <p><strong>Conversion from string &quot;a&quot; to type 'Boolean' is not valid.</strong></p>
  <p>Here's my code:</p>
  <p>Module Module1</p>
  <pre><code>Sub Main()
      Dim Selection As String
  
      Console.WriteLine(&quot;Please select your function:&quot;)
      Console.WriteLine(&quot;* To convert binary to decimal, press A,&quot;)
      Console.WriteLine(&quot;* Or to convert decimal to binary, press B&quot;)
  
      Selection = Console.ReadLine
  
      If Selection = &quot;A&quot; Or &quot;a&quot; Then
          Console.WriteLine(&quot;This will be A&quot;)
      ElseIf Selection = &quot;B&quot; Or &quot;b&quot; Then
          Console.WriteLine(&quot;This will be B&quot;)
      ElseIf Selection = Not &quot;A&quot; Or &quot;a&quot; Or &quot;B&quot; Or &quot;b&quot; Then
          Console.WriteLine(&quot;Please try again&quot;)
          Do Until Selection = &quot;A&quot; Or &quot;a&quot; Or &quot;B&quot; Or &quot;b&quot;
          Loop
      End If
  
  
  End Sub
  </code></pre>
  <p>What should be the correct usage of the Or in this piece of code to make it function correctly?</p>