Replace a text with all alphabet VB.NET - vb.net

Question

I just stopped by this error
System.NullReferenceException was unhandled HResult=-2147467261
Message=Object reference not set to an instance of an object.
Source=System.Windows.Forms StackTrace:
at System.Windows.Forms.RichTextBox.StreamIn(String str, Int32 flags)
at System.Windows.Forms.RichTextBox.set_SelectedText(String value)
at Novania_JAV_Viewer_EncDec.Form1.Button1_Click(Object sender, EventArgs ef) in c:\users\toshiba\documents\visual studio
2010\Projects\Novania JAV Viewer EncDec\Novania JAV Viewer
EncDec\Form1.vb:line 91
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr
dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32
reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32
reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(ApplicationContext context)
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[]
commandLine)
at Novania_JAV_Viewer_EncDec.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext
executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean
preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart() InnerException:
and this is my whole code, I am trying to replace all alphabet in one word, and it needs to replace one by one, and one by one variable.
the error is located here ("title") word
Do Until RichTextBox1.Find("titelz") = -1
RichTextBox1.Find("titelz")
RichTextBox1.SelectedText = titel
and this is my whole form class code
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
RichTextBox1.LoadFile("template.rtf")
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal ef As System.EventArgs) Handles Button1.Click
Dim A As String
Replace(TextBox1.Text, "A", "5TY5")
Console.WriteLine(A)
Dim B As String
Replace(A, "B", "WEE")
Console.WriteLine(B)
Dim C As String
Replace(B, "C", "23RW")
Console.WriteLine(C)
Dim D As String
Replace(C, "D", "RW4R")
Console.WriteLine(D)
Dim E As String
Replace(D, "E", "DFS")
Console.WriteLine(E)
Dim F As String
Replace(E, "F", "R5")
Console.WriteLine(F)
Dim G As String
Replace(F, "G", "QWEDQ")
Console.WriteLine(G)
Dim H As String
Replace(G, "H", "ZDCZ")
Console.WriteLine(H)
Dim I As String
Replace(H, "I", "VGHN")
Console.WriteLine(I)
Dim J As String
Replace(I, "J", "ZSC")
Console.WriteLine(J)
Dim K As String
Replace(J, "K", "ZSD")
Console.WriteLine(K)
Dim L As String
Replace(K, "L", "WER")
Console.WriteLine(L)
Dim M As String
Replace(L, "M", "GN")
Console.WriteLine(M)
Dim N As String
Replace(M, "N", "xfv")
Console.WriteLine(N)
Dim O As String
Replace(N, "O", "DAASAD")
Console.WriteLine(O)
Dim P As String
Replace(O, "P", "WET")
Console.WriteLine(P)
Dim Q As String
Replace(P, "Q", "DFCV")
Console.WriteLine(Q)
Dim R As String
Replace(Q, "R", "ADSDA")
Console.WriteLine(R)
Dim S As String
Replace(R, "S", "SGFDG")
Console.WriteLine(S)
Dim T As String
Replace(S, "T", "SFSFD")
Console.WriteLine(T)
Dim U As String
Replace(T, "U", "AWDAD")
Console.WriteLine(U)
Dim V As String
Replace(U, "V", "RERE")
Console.WriteLine(V)
Dim W As String
Replace(V, "W", "GBGDBB")
Console.WriteLine(W)
Dim X As String
Replace(W, "X", " AWDAW ")
Console.WriteLine(X)
Dim Y As String
Replace(X, "Y", "AWDEAVA")
Console.WriteLine(Y)
Dim Z As String
Replace(Y, "Z", "AWEDWADW")
Console.WriteLine(Z)
Dim titel As String = Z
Do Until RichTextBox1.Find("titelz") = -1
RichTextBox1.Find("titelz")
RichTextBox1.SelectedText = titel
Loop
RichTextBox2.Text = RichTextBox1.Text
RichTextBox1.Clear()
RichTextBox1.LoadFile("template.rtf")
End Sub
End Class

Answer 1

In order to do the replace, I'd try the following code...
It uses a Dictionary type variable. They are used in .NET quite a lot as some sort of associative array.
' First, create dictionary that you can loop through.
' This variable is created on form level (so only once)
' and contains all the "words" as key-value pairs.
' So you can search for key and replace with value.
Dim replaceDictionary As New Dictionary(Of String, String) From {{"A", "5TY5"}, _
{"B", "WEE"}, _
{"C", "23RW"}, _
{"D", "RW4R"}, _
{"E", "DFS"}, _
{"F", "R5"}, _
{"G", "QWEDQ"}, _
{"H", "ZDCZ"}, _
{"I", "VGHN"}, _
{"J", "ZSC"}, _
{"K", "ZSD"}, _
{"L", "WER"}, _
{"M", "GN"}, _
{"N", "xfv"}, _
{"O", "DAASAD"}, _
{"P", "WET"}, _
{"Q", "DFCV"}, _
{"R", "ADSDA"}, _
{"S", "SGFDG"}, _
{"T", "SFSFD"}, _
{"U", "AWDAD"}, _
{"V", "RERE"}, _
{"W", "GBGDBB"}, _
{"X", " AWDAW "}, _
{"Y", "AWDEAVA"}, _
{"Z", "AWEDWADW"}
}
Private Sub btnReplace_Click(sender As System.Object, e As System.EventArgs) Handles btnReplace.Click
' Declare temporary variable to store text
Dim tmpText As String = txtTitel.Text
' Loop through dictionary
For Each replaceItem In replaceDictionary
' Replace key ("A" etc.) with value ("5TY5" etc.)
' and store in temporary variable
tmpText = Replace(tmpText, replaceItem.Key, replaceItem.Value)
Next
'Display text
txtTitel.Text = tmpText
End Sub
Now for your "find" part... nothing like "titelz" is going to be changed with above code (only caps), so if it was in there, it stays in there.
So I have no idea what to do with that...
Edit
For the record: this goes for a long line of replaces... Once you've replaced all the A's in your string, the T from "5TY5" will also be replaced.
If you don't want this, you'll have to split the original text into characters and start checking them one by one.
Checking title string one letter at a time
There are a few changes to above code:
Dictionary is now of type (Char, String) instead of 2 strings.
The title is stored in a seperate variable in order to keep working with the orignal title text.
Instead of looping through the dictionary, you loop through the title text one letter at a time.
The code is documented with comments and should be pretty self-explanatory.
Good luck!
' First, create dictionary that you can loop through.
' This variable is created on form level (so only once)
' and contains all the "words" as key-value pairs.
' So you can search for key and replace with value.
Dim replaceDictionary As New Dictionary(Of Char, String) From {{"A", "5TY5"}, _
{"B", "WEE"}, _
{"C", "23RW"}, _
{"D", "RW4R"}, _
{"E", "DFS"}, _
{"F", "R5"}, _
{"G", "QWEDQ"}, _
{"H", "ZDCZ"}, _
{"I", "VGHN"}, _
{"J", "ZSC"}, _
{"K", "ZSD"}, _
{"L", "WER"}, _
{"M", "GN"}, _
{"N", "xfv"}, _
{"O", "DAASAD"}, _
{"P", "WET"}, _
{"Q", "DFCV"}, _
{"R", "ADSDA"}, _
{"S", "SGFDG"}, _
{"T", "SFSFD"}, _
{"U", "AWDAD"}, _
{"V", "RERE"}, _
{"W", "GBGDBB"}, _
{"X", " AWDAW "}, _
{"Y", "AWDEAVA"}, _
{"Z", "AWEDWADW"}
}
Private Sub btnReplace_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnReplace.Click
' Declare temporary variable to store text
Dim tmpTitle As String = txtTitel.Text
Dim tmpText As String = ""
Dim tmpLetter As Char
' Loop through title string
Dim i As Integer = 0
Do While (i < tmpTitle.Length)
' Increase counter
i += 1
' Save next letter in tmpLetter
tmpLetter = Mid(tmpTitle, i, 1)
' Check for key in dictionary
If replaceDictionary.ContainsKey(tmpLetter) Then
' When found, append associated value to tmpText
tmpText &= replaceDictionary(tmpLetter)
Else
' Not found: use letter from title string
tmpText &= CStr(tmpLetter)
End If
Loop
'Display text
txtTitel.Text = tmpText
End Sub