Crystal report export in excel - vb.net

Question

Having problem in my crystal report, exporting to excel. Can somebody help me how to code or any suggestion code that will catch if the file you exported is already exist?
For example, you exported lotinfo the next will be lotinfo2 then lotinfo3 etc, my code is always exporting single file and single name.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Try
Dim CrExportOptions As ExportOptions
Dim CrDiskFileDestinationOptions As New _
DiskFileDestinationOptions()
Dim CrFormatTypeOptions As New ExcelFormatOptions
CrDiskFileDestinationOptions.DiskFileName = _
"c:\Lot Enterprise Information.xls"
CrExportOptions = crypt.ExportOptions
With CrExportOptions
.ExportDestinationType = ExportDestinationType.DiskFile
.ExportFormatType = ExportFormatType.Excel
.DestinationOptions = CrDiskFileDestinationOptions
.FormatOptions = CrFormatTypeOptions
End With
crypt.Export()
MessageBox.Show("LOT ENTERPRISE INFORMATION IS SUCCESSFULLY EXPORTED!, LOCATED AT DRIVE C:", "PLEASE CHECK AT DRIVE C:", MessageBoxButtons.OK, MessageBoxIcon.Information)
Catch ex As Exception
MsgBox("Please Select Specific date to convert!")
'MsgBox(ex.ToString)
End Try
End Sub

Answer 1

I've been using this function for quite some time now. Just fix it up depending on your use.
Private Function fileExists(ByVal path As String, ByVal filename As String) As String
' This function basically adds a counter when the file already exists
' eg filename
' filename(1)
' filename(2)
Dim counter As Integer = 0
Dim orginialFileName As String = System.IO.Path.Combine(path, filename)
Dim newFileName = orginialFileName
Dim extension As String = ""
Dim testIndex As Integer = 0
While File.Exists(newFileName)
counter = counter + 1
extension = newFileName.Substring(newFileName.LastIndexOf("."))
filename = filename.Substring(0, filename.LastIndexOf("."))
testIndex = filename.LastIndexOf("(")
If testIndex <> -1 Then
filename = filename.Substring(0, testIndex)
End If
newFileName = String.Format("{0}({1})", System.IO.Path.Combine(path, filename), counter.ToString())
filename = String.Format("{0}({1})", filename, counter.ToString())
newFileName += extension
filename += extension
End While
Return filename
End Function
example usage
Dim output as string
output = fileExists("C:\test", "file.xls")
MsgBox(output)
This link might also be useful for you.
EDIT:
You can use it before your Try-Catch block
Dim fullPath As String = "C:\fileinfo.xls"
Dim directory, output, filename As String
If File.Exists(fullPath) Then
directory = fullPath.Substring(0, fullPath.LastIndexOf("\"))
filename = fullPath.Substring(fullPath.LastIndexOf("\") + 1)
output = fileExists(directory, filename)
fullPath = path.combine(directory,output)
End If
Then change this part
CrDiskFileDestinationOptions.DiskFileName = _
"c:\Lot Enterprise Information.xls"
To
CrDiskFileDestinationOptions.DiskFileName = _
fullPath