Deleting a txt file

For example I have a open file dialog, which opens a txt file.

When I press a specific button, it clears the whole text file.

How do I do that?

What application do you open the text file with? If it's displayed in a textbox or richtextbox in your own application then you just clear the textbox (or richtextbox).

I did not show any of the content from the text file in any controls. The result is that the text file is now blank.

So you don't actually want to delete the whole file, just remove it's contents?

vb.net Code:

Dim OFD As New OpenFileDialog
        OFD.Filter = ".txt Files (*.txt)|*.txt" 'might have done the filter wrong, i always forget :P
 
        If OFD.ShowDialog = Windows.Forms.DialogResult.OK Then
            Dim finfo As New IO.FileInfo(OFD.FileName)
            If finfo.Extension.ToLower = ".txt" Then
                IO.File.Delete(OFD.FileName)
                IO.File.Create(OFD.FileName)
            End If
        End If

There are numerous ways to do this, this one just deletes the existing file and creates a new one in place of it. You could also use streamreader set on "append - False" and write nothing to the file or whatever you want really.

Will I be able to write that file afterwards?

Im afraid the error "file being used by other" will show up.

yes you will be able to write to the file, just try it out and see!

Code:

---

Dim OFD As New OpenFileDialog
OFD.Filter = ".txt Files (*.txt)|*.txt"

        If OFD.ShowDialog = Windows.Forms.DialogResult.OK Then
            Dim finfo As New IO.FileInfo(OFD.FileName)
            If finfo.Extension.ToLower = ".txt" Then
                IO.File.Delete(OFD.FileName)
                IO.File.Create(OFD.FileName)
            End If
        End If

Dim Write As New System.IO.Streamwriter(OFD.Filename)

Write.WriteLine("Test Line")

---

I typed that in and it gave me the "file is being used in other process" error. :confused:

Code:

---

Dim Write As New System.IO.Streamwriter(OFD.Filename)

Write.WriteLine("Test Line")

Write.Close()

---

Dont forget to close the stream! :)

ah ok it seems I've resolved the question.

Thanks guys!

Code:

---

Dim OFD As New OpenFileDialog
OFD.Filter = ".txt Files (*.txt)|*.txt"

        If OFD.ShowDialog = Windows.Forms.DialogResult.OK Then
            Dim finfo As New IO.FileInfo(OFD.FileName)
            If finfo.Extension.ToLower = ".txt" Then
                IO.File.Delete(OFD.FileName)
                IO.File.Create(OFD.FileName)
                Using sWrite As New IO.Streamwriter(OFD.Filename)
                      sWrite.WriteLine("Test Line")
                End Using
            End If
        End If

---

Try that out, I changed up some stuff and moved your streamwriter argument. Are you sure you dont have the txt file open somewhere at the time you're trying to delete it?

Ps: that is too complicated :)

Here I simplified a little so that you can learn from it:

Code:

---

        Dim OFD As New OpenFileDialog

        OFD.Filter = ".txt Files (*.txt)|*.txt"

        If OFD.ShowDialog = Windows.Forms.DialogResult.OK Then
            Dim finfo As New IO.FileInfo(OFD.FileName)
            If finfo.Extension.ToLower = ".txt" Then
                'If File exists, delete it.
                If FileIO.FileSystem.FileExists(OFD.FileName) = True Then
                    Kill(OFD.FileName)
                End If
                'Write your data
                Dim Write As New System.IO.StreamWriter(OFD.FileName)
                Write.WriteLine("Test Line")
                Write.Close()

            End If
        End If

---

Okay fixed it so much easier!

vb.net Code:

Dim OFD As New OpenFileDialog
            OFD.Filter = ".txt Files (*.txt)|*.txt"
 
            If OFD.ShowDialog = Windows.Forms.DialogResult.OK Then
                Dim fInfo As New IO.FileInfo(OFD.FileName)
                If fInfo.Extension.ToLower = ".txt" Then
 
                    Dim fStream As New IO.FileStream(OFD.FileName, IO.FileMode.Truncate)
                    fStream.Close()
                    Using sWrite As New IO.StreamWriter(OFD.FileName)
                        sWrite.WriteLine("Test Line")
                    End Using
                End If
            End If

Oh yeah, if what you're trying to do is clear the text file so that you can start adding lines from scratch, the simplest way to do this is very simple:

vb.net Code:

Dim OFD As New OpenFileDialog
        OFD.Filter = ".txt Files (*.txt)|*.txt"
 
        If OFD.ShowDialog = Windows.Forms.DialogResult.OK Then
            Dim fInfo As New IO.FileInfo(OFD.FileName)
            If fInfo.Extension.ToLower = ".txt" Then
                Using sWrite As New IO.StreamWriter(OFD.FileName, False)
                    '//write here
                End Using
            End If
        End If