title: VB.net - 'Property Chars: Is ReadOnly' error in replacing letter of a string
body: <p>This private sub keeps telling me that 'Property Chars: Is ReadOnly'.</p>
  
  <p>Where have I gone wrong? StrWord is a string, e.g. 'banana'.</p>
  
  <p>What I was hoping it would do is loop through the word, and if the 'guess' (a single letter) matches any letter in the string (StrWord), it would replace it in the corresponding letter in the textbox of the word.</p>
  
  <p>So hangman, more or less.</p>
  
  <p>Thanks and regards,<br>
  Cameron.</p>
  
  <pre><code>Private Sub Lookup(ByVal Guess)
      Dim Count As Integer = 0
      For Each Character As Char In StrWord
          If Character = Guess Then
              txtResult.Text(Count) = Guess
          Else
              Count += 1
          End If
      Next
  End Sub
  </code></pre>