Error Handling: load text file into TextBox

25 Apr 2006 5:35 AM

jzheng22

Hi all,

I am new to VB .NET. I am currently wring a simple GUI, a TextBox
(multilined),
a button and an OpenFileDialog. When user click the button, the
OpenFileDialog
fired and after user select a file, the content of the text file would
be loaded
(appended) into the TextBox.
Note: I am not using RichTextBox.Loadfile() method.

My code is working, however, when i tested it by loading large .exe
file into the
textbox, the program freezes. I wondered if anyone could help me with
these:
1) check if the selected file is a text file
2) if user choose a very large file, no matter what format it is, the
code should
report an exception and keep running.

Many thanks.

P.S. My current error handlers using "Try" are not working, code
attached below:

Try
    If OpenFileDialog1.ShowDialog() =
System.Windows.Forms.DialogResult.OK _
            And (OpenFileDialog1.FileName.Length) > 0 Then

            Dim objReader As New StreamReader(OpenFileDialog1.FileName)
            Dim sLine As String = ""
            Do
                    sLine = objReader.ReadLine()
                    If Not sLine Is Nothing Then
                             TextBox1.Text = TextBox1.Text & "; " &
sLine
                    End If
                End If
            Loop Until sLine Is Nothing
            objReader.Close()
      End If
Catch ex As Exception
                    MessageBox.Show("Error when open files." & vbCrLf &
ex.Message)
                    TextBox1.Clear()
                    TextBox1.Focus()
                    Exit Sub
End Try

25 Apr 2006 6:19 AM

Cor Ligthert [MVP]

JsHeng,

There is a size bug in the Version Net 1.1 in the textbox

Can it be that you are using a version from before 2005?

Cor

<jzhen***@gmail.com> schreef in bericht
Show quoteHide quote

news:1145943343.806444.161840@v46g2000cwv.googlegroups.com...
> Hi all,
>
> I am new to VB .NET. I am currently wring a simple GUI, a TextBox
> (multilined),
> a button and an OpenFileDialog. When user click the button, the
> OpenFileDialog
> fired and after user select a file, the content of the text file would
> be loaded
> (appended) into the TextBox.
> Note: I am not using RichTextBox.Loadfile() method.
>
> My code is working, however, when i tested it by loading large .exe
> file into the
> textbox, the program freezes. I wondered if anyone could help me with
> these:
> 1) check if the selected file is a text file
> 2) if user choose a very large file, no matter what format it is, the
> code should
> report an exception and keep running.
>
> Many thanks.
>
> P.S. My current error handlers using "Try" are not working, code
> attached below:
>
> Try
>    If OpenFileDialog1.ShowDialog() =
> System.Windows.Forms.DialogResult.OK _
>            And (OpenFileDialog1.FileName.Length) > 0 Then
>
>            Dim objReader As New StreamReader(OpenFileDialog1.FileName)
>            Dim sLine As String = ""
>            Do
>                    sLine = objReader.ReadLine()
>                    If Not sLine Is Nothing Then
>                             TextBox1.Text = TextBox1.Text & "; " &
> sLine
>                    End If
>                End If
>            Loop Until sLine Is Nothing
>            objReader.Close()
>      End If
> Catch ex As Exception
>                    MessageBox.Show("Error when open files." & vbCrLf &
> ex.Message)
>                    TextBox1.Clear()
>                    TextBox1.Focus()
>                    Exit Sub
> End Try
>

25 Apr 2006 6:30 AM

Peter Proost

Hi you can use the openfiledialog filter property to allow only textfiles,
see code below

Dim myReader As StreamReader
OpenFileDialog1.Filter = "Text files|*.txt"
OpenFileDialog1.CheckFileExists = True
OpenFileDialog1.CheckPathExists = True
OpenFileDialog1.Multiselect = False
If OpenFileDialog1.ShowDialog = DialogResult.OK Then
            try
                myReader = New StreamReader(OpenFileDialog1.FileName)
                TextBox1.Text = myReader.ReadToEnd
                myReader.Close()
            catch ex As Exception
                messageBox.show(ex.ToString)
            end try
End If

Hope this helps,

Greetz Peter

--
Programming today is a race between software engineers striving to build
bigger and better idiot-proof programs, and the Universe trying to produce
bigger and better idiots. So far, the Universe is winning. (Rich Cook)

<jzhen***@gmail.com> schreef in bericht

Show quoteHide quote

news:1145943343.806444.161840@v46g2000cwv.googlegroups.com...
> Hi all,
>
> I am new to VB .NET. I am currently wring a simple GUI, a TextBox
> (multilined),
> a button and an OpenFileDialog. When user click the button, the
> OpenFileDialog
> fired and after user select a file, the content of the text file would
> be loaded
> (appended) into the TextBox.
> Note: I am not using RichTextBox.Loadfile() method.
>
> My code is working, however, when i tested it by loading large .exe
> file into the
> textbox, the program freezes. I wondered if anyone could help me with
> these:
> 1) check if the selected file is a text file
> 2) if user choose a very large file, no matter what format it is, the
> code should
> report an exception and keep running.
>
> Many thanks.
>
> P.S. My current error handlers using "Try" are not working, code
> attached below:
>
> Try
>     If OpenFileDialog1.ShowDialog() =
> System.Windows.Forms.DialogResult.OK _
>             And (OpenFileDialog1.FileName.Length) > 0 Then
>
>             Dim objReader As New StreamReader(OpenFileDialog1.FileName)
>             Dim sLine As String = ""
>             Do
>                     sLine = objReader.ReadLine()
>                     If Not sLine Is Nothing Then
>                              TextBox1.Text = TextBox1.Text & "; " &
> sLine
>                     End If
>                 End If
>             Loop Until sLine Is Nothing
>             objReader.Close()
>       End If
> Catch ex As Exception
>                     MessageBox.Show("Error when open files." & vbCrLf &
> ex.Message)
>                     TextBox1.Clear()
>                     TextBox1.Focus()
>                     Exit Sub
> End Try
>