Need help editing a file in vb.net

[chrrox]

I have got my program to lead the file into the rich text box and I can also paste a short amount of values into it and save the file and it works as expected. But If I click load and then edit a larger file my program hangs when I go to save. Is there a better way to do this code?


Public Class HeaderChange
Public Shared Function ReadAllBytes( _
ByVal path As String _
) As Byte()

End Function



Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim OpenFileDialog As New Windows.Forms.OpenFileDialog



OpenFileDialog.Filter = "All Files (*)|*|All Files (*.*)|*.*"

If (OpenFileDialog.ShowDialog(Me) = System.Windows.Forms.DialogResult.OK) Then



Dim FileName As String = OpenFileDialog.FileName

Dim s As String = System.IO.File.ReadAllText(OpenFileDialog.FileName)

Dim encoding As New System.Text.ASCIIEncoding()

Dim b As Byte() = encoding.GetBytes(s)

Dim sb As New System.Text.StringBuilder()

For Each singleByte As Byte In b


sb.AppendFormat("{0:x2}", singleByte)
Next
RichTextBox1.Text = sb.ToString()
MsgBox("File Loaded!")

End If
End Sub

Private Sub RichTextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles RichTextBox1.TextChanged

End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click

Dim FILE_NAME As String

If SaveFileDialog1.ShowDialog() = Windows.Forms.DialogResult.OK Then

FILE_NAME = SaveFileDialog1.FileName

Dim a As String = RichTextBox1.Text

Dim b As String = ""

Dim i As Integer



For i = 0 To a.Length - 2 Step 2

b = b & Chr(CInt("&H" & a.Substring(i, 2)))

Next





Dim objWriter As System.IO.StreamWriter

objWriter = New System.IO.StreamWriter(FILE_NAME)

objWriter.Write(b)

objWriter.Close()

End If
End Sub

Private Sub HeaderChange_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

End Sub

Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click

End Sub
End Class
thanks in advance :)