[RESOLVED] deleting a file

hey guys. If the user chooses to save over an existing file, I want to essentially delete the file first, then re-create it and save to it. Basically, I don't want to append to the file. I want to completely overwrite. However, I am just running into all these snags. It basially deletes the file as soon as the savefiledialog box opens. before, it would simply append. Can anyone spot my problem?

code Code:

Try
            With SaveDataLogDialog
                .FileName = DFileName
                If File.Exists(DFileName) = True Then
                    File.Delete(DFileName)
                End If
 
                
                .Filter = "CSV files (*.csv)|*.csv|" & "All files|*.*"
                .DefaultExt = "csv"
                .AddExtension = True
                .CreatePrompt = True
                .OverwritePrompt = True
                .Title = "Save Data Log As..."
 
            
                If .ShowDialog() = DialogResult.OK Then
                 
                    DFileName = .FileName
 
                End If
 
            End With
        Catch es As Exception
            MessageBox.Show(es.Message)
        Finally
            If Not (sw Is Nothing) Then
                datalogSW.Close()
            End If
        End Try

Hey,

Try putting this code:

Code:

---

    .FileName = DFileName
                If File.Exists(DFileName) = True Then
                    File.Delete(DFileName)
                End If

---

Here:

Code:

---

If .ShowDialog() = DialogResult.OK Then
    .FileName = DFileName
                If File.Exists(DFileName) = True Then
                    File.Delete(DFileName)
                End If               

                    DFileName = .FileName

                End If

---

Gary

that was originally what I had, but it just appends onto the end of the file. I just your method again to make sure and it still functions the same way

Have you tried stepping through your code in the debugger?

If the file isn't getting deleted, then it is because this if statement:

Code:

---

If File.Exists(DFileName) = True Then

---

If not evaluating to true, and the only way that would happen is if the file doesn't already exist. What is the value of DFileName at runtime. Is the file there?

Gary

i see...somehow, DFilename isn't being created when i press ok. It skips right over the delete. But I don't understand because I am picking a file that exists (it opens before runtime), and I get the overwrite prompt telling me the file already exists...hmmmmm...How do I see what values are held by variables with the debugger?

Once you hit a break point, either:

1) hover your mouse over the variable in question
2) Open the Locals Window
3) Drag the variable into the Watch Window

Gary

DFileName stays completely empty the entire time.. hm. the only other time I use DfileName is in a streamwriter that writes data on ever timer_tick in a seperate sub...

Without seeing the rest of your code, it is going to be difficult to suggest anything.

If would search your code for:

Code:

---

DFileName =

---

Find out all the places that that variable is being used. It might be the case that you need to do this step first:

Code:

---

DFileName = .FileName

---

Then delete, but really you have to say exactly what you want your application to do.

Gary

There's no need to delete the file first, by the way. You can always set its length to zero:

Code:

---

Dim fs As New IO.FileStream("filename.ext", IO.FileMode.OpenOrCreate, IO.FileAccess.Write, IO.FileShare.None)
If fs.Length > 0 Then fs.SetLength(0)

' Write your data here

---

Ok, i've tried every method above...but DFileName still stays "Nothing" throughout the test. It never receives a value. Here is all the pertinent code...I tried putting DFileName = .Filename in the FileOK event raised by the savefiledialog, but that didn't work either...I am not good at this stuff so thanks for sticking with me so far.

code Code:

Private DFileName As String
Private DataText1 As String
Private DataText2 As String
Private SFileName As String
Private datalogSW As System.IO.StreamWriter
 
Try
With SaveDataLogDialog
 
 
 
.Filter = "CSV files (*.csv)|*.csv|" & "All files|*.*"
.DefaultExt = "csv"
.AddExtension = True
.CreatePrompt = True
.OverwritePrompt = True
.Title = "Save Data Log As..."
.CheckPathExists = True
 
If .ShowDialog() = DialogResult.OK Then
.FileName = DFileName
If File.Exists(DFileName) = True Then
File.Delete(DFileName)
End If
 
 
End If
 
End With
Catch es As Exception
MessageBox.Show(es.Message)
Finally
If Not (sw Is Nothing) Then
datalogSW.Close()
End If
End Try
 
End Sub
 
Private Sub SaveTimer_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles SaveTimer.Tick
 
'Dim fs As New IO.FileStream(DFileName, IO.FileMode.OpenOrCreate, IO.FileAccess.Write, IO.FileShare.None)
'If fs.Length > 0 Then fs.SetLength(0)
 
datalogSW = My.Computer.FileSystem.OpenTextFileWriter(DFileName, True)
DataText1 = CurrentPositionValue.Text
DataText2 = CurrentForceValue.Text
datalogSW.WriteLine(DataText1 & "," & DataText2)
datalogSW.Close()
 
End Sub

you got this line wrong

If .ShowDialog() = DialogResult.OK Then
.FileName = DFileName

should be inverted

nevermind. got it. should have been

DFileName = .Filename

instead of the other way around...duhhh.....thanks for your help guys

Doh!! I think I saw that, but just never said anything, as I thought you were setting it elsewhere as well.

Glad you got it sorted!

Gary

haha. you did say it in post #8 now that I look back. I don't know why I didn't try it sooner. I think I just figured that's what I did because the way I had it made absolutely no sense. It's alright though--everyone got rep! haha