String Manipulation with no delimiter - vb.net

Question

I have a string where I need to replace every character in that string with another value. That string has no delimiter. Is it possible to step through that string and replace every value with a set of predetermined values? I would like to keep it to one function as it is going to live within SSRS
Dim stringToChange As String = "123456ALWRYA"
I would then have to step through the string and replace all off the current values with new ones.
i.e. A=001, B=002, 1=101, 2=102, etc.
Is this possible if the string does not have a delimiter?
Thanks in advance!

Answer 1

SSRS Custom code has a pretty limited dialect, but this worked for me.
Add the following to the report Custom Code:
Function SingleReplace (SingleChar As String) As String
Select Case SingleChar
Case "A"
SingleReplace = "001"
Case "B"
SingleReplace = "002"
Case Else
SingleReplace = SingleChar
End Select
End Function
Function CustomReplace (BaseString As String) As String
Dim NewString As New System.Text.StringBuilder
For Each SingleChar As Char in BaseString
NewString.Append(SingleReplace(SingleChar))
Next
Return NewString.ToString()
End Function
Call this in a report expression with:
=Code.CustomReplace(Fields!MyString.Value)
Works for me in a simple report/table:

Answer 2

This is basically what Styxxy suggested...with a Dictionary for the looking up the values:
Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
Dim stringToChange As String = "123456ALWRYA"
Debug.Print(stringToChange)
Dim changedString = ConvertString(stringToChange)
Debug.Print(changedString)
End Sub
Private Function ConvertString(ByVal inStr As String) As String
Static dict As New Dictionary(Of Char, String)
If dict.Count = 0 Then
dict.Add("A"c, "001")
dict.Add("B"c, "002")
dict.Add("1"c, "101")
dict.Add("2"c, "102")
' ... etc ...
End If
Dim sb As New System.Text.StringBuilder
For Each c As Char In inStr.ToUpper
If dict.ContainsKey(c) Then
sb.Append(dict(c))
Else
' ... possibly throw an exception? ...
sb.Append(c)
End If
Next
Return sb.ToString
End Function