Problem downloading a file and saving using a SaveFileDialog!!
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  1. #1
    Join Date
    Oct 2012
    Posts
    7

    Problem downloading a file and saving using a SaveFileDialog!!

    Hi
    I am new to programming. I am trying to download contents from a datatable on to a txt file and also I am trying to save the file using the SaveFileDialog. I am getting errors. The following is the code

    Code:
    Protected Sub ThreadMethod()
    
    
            exportToFile(RadioButtonListDelimiter.SelectedValue)
    
            'Set the Save dialog properties
    
        End Sub
    
    
    
        Protected Sub exportToFile(ByVal delimiter As String)
    
    
            'CREATING A FILE - Open or Create the file
    
            Dim dt As DataTable
            Dim selectedItems As ArrayList
            Dim sb As New StringBuilder()
            Dim delim As String = delimiter
    
            If Session("selectedItems") Is Nothing Then
                selectedItems = New ArrayList
            Else
                selectedItems = CType(Session("selectedItems"), ArrayList)
            End If
            
            'get the store codes from the radgrid into an array list
            For Each item As GridItem In RadGrid3.MasterTableView.Items
                If TypeOf item Is GridDataItem Then
                    Dim dataItem As GridDataItem = CType(item, GridDataItem)
                    Dim id As String = dataItem.OwnerTableView.DataKeyValues(dataItem.ItemIndex)("Store Code").ToString()
                    selectedItems.Add(id)
                End If
            Next
            'iterate the arraylist to get the corresponding store information
            For m = 0 To selectedItems.Count - 1
                dt = (FileManager.GetParentCompanyStoreSearchExportFile(selectedItems(m).ToString))
    
                If m = 0 Then
                    For i As Integer = 0 To dt.Columns.Count - 1
                        sb.Append(dt.Columns(i).ColumnName + delimiter)
                    Next
                End If
                sb.Append(Environment.NewLine)
    
                For j As Integer = 0 To dt.Rows.Count - 1
                    For k As Integer = 0 To dt.Columns.Count - 1
                        sb.Append(dt.Rows(j)(k).ToString() + delimiter)
                    Next
                Next
            Next
            sb.Append(Environment.NewLine)
    
            Response.Clear()
            Response.ContentType = "text/plain"
            Response.AddHeader("content-disposition", "attachment;filename=PCSInfoFile.txt")
            Response.Write(sb.ToString())
    
    
            Dim objSaveFileDialog As New Windows.Forms.SaveFileDialog
    
            With objSaveFileDialog
                '.InitialDirectory = "C:\Documents and Settings\crodnavar\My Documents\Downloads"
                .DefaultExt = "txt"
                .FileName = "PCSInfoFile.txt"
                .Filter = "Text files (*.txt)|*.txt|All files (*.*)|*.*"
                .FilterIndex = 1
                .OverwritePrompt = True
                .Title = "Export File to"
            End With
    
    
            'Show the Save dialog and if the user clicks the Save button,
            'save the file
    
    
            If objSaveFileDialog.ShowDialog() = Windows.Forms.DialogResult.OK Then
    
                Dim FilePath As String
    
                FilePath = System.IO.Path.Combine(My.Computer.FileSystem.SpecialDirectories.MyDocuments, objSaveFileDialog.FileName)
                'Replace the contents of the file
                My.Computer.FileSystem.WriteAllText(FilePath, "C:\Documents and Settings\crodnavar\My Documents\Downloads\PCSInfoFile.txt", True)
    
                Response.Flush()
                Response.End()
                'MsgBox("Please Search for a store to be exported.", MsgBoxStyle.Exclamation, "Alert")
                'Else
    
            End If
            'Try
    
            'Catch fileException As Exception
            '    Throw fileException
            '    'Cleanup()
            '    objSaveFileDialog.Dispose()
            '    objSaveFileDialog = Nothing
            'End Try
        End Sub
    
        Protected Sub BtnOk_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles BtnOk.Click
            RadGrid3.Visible = True
    
            ExportDelimiterDiv.Visible = False
            ExportDelimiterDiv.Style.Add("display", "none")
    
            Dim newThread As Thread = New Thread(New ThreadStart(AddressOf ThreadMethod))
            newThread.ApartmentState = ApartmentState.STA
            newThread.Start()
            '
        End Sub
    I am getting error as Null reference at the response.clear(). Not sure why that is happening. Please Help.
    Last edited by GremlinSA; October 28th, 2012 at 02:23 PM. Reason: added code tags

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