Question

I have a page which lists all the files in a particular folder (all PDFs), using a data-table and gridview.

I’m currently sorting this table by the filename (by using a dataview), which isn’t that helpful, and I want the gridview of files sorted by the file created or file modified date (as recorded in Windows).

If that’s not possible, a second option would be to extract the date from the file name string (no problem doing that), and sort the dataview/datatable or gridview based on that.
Example Filename: DailySalesReport-1-15-2010. My only hangup with this is how do I sort on date, when it’s a string value? Convert to date? How would I sort the whole dataset based on this converted value?

Thanks for any ideas!

Protected Sub PageLoad(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

    If Not IsPostBack Then
        Dim dt As New DataTable()
        dt.Columns.Add("Daily Reports", Type.[GetType]("System.String"))

        For Each name As [String] In System.IO.Directory.GetFiles(Server.MapPath("~\reports\pdf\")) '"
                dt.Rows.Add(New Object() {name})
        Next

        Dim dv As DataView = dt.DefaultView
        dv.Sort = dt.Columns(0).ToString + " " + "desc"
        dt = dv.ToTable

        Me.gvDaily.DataSource = dt
        Me.gvDaily.DataBind()

    End If
End Sub



Protected Sub gvDaily_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)

    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim hl As New HyperLink()
        hl.NavigateUrl = "~\reports\pdfs\" + e.Row.Cells(0).Text '"
        hl.Text = "Daily Report"
        e.Row.Cells(0).Text = ""
        e.Row.Cells(0).Controls.Add(hl)
    End If

End Sub


<asp:GridView ID="gvDaily" runat="server" Height="80px" Width = "180px" CssClass="tableText"    
          OnRowDataBound="gvDaily_RowDataBound">
          <RowStyle HorizontalAlign="center" />                
</asp:GridView>

Answer 1

Try this new page load. With a “FileDate” column.

Private Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    If Not IsPostBack Then
        Dim dt As New Data.DataTable()
        dt.Columns.Add("Daily Reports", Type.[GetType]("System.String"))
        dt.Columns.Add("FileDate", GetType(System.DateTime))

        For Each name As [String] In System.IO.Directory.GetFiles(Server.MapPath("~\reports\pdf\"))

            Dim fi As New System.IO.FileInfo(name)

            dt.Rows.Add(New Object() {name, fi.LastWriteTime})
        Next

        Dim dv As DataView = dt.DefaultView
        dv.Sort = dt.Columns("FileDate").ColumnName & " " & "desc"
        dt = dv.ToTable

        Me.gvDaily.DataSource = dt
        Me.gvDaily.DataBind()

    End If
End Sub

To show just the column you want, use this as your Gridview.

<asp:GridView ID="gvDaily" runat="server" Height="80px" Width = "180px" CssClass="tableText"    
          OnRowDataBound="gvDaily_RowDataBound" AutoGenerateColumns="false">
          <RowStyle HorizontalAlign="center" />
    <Columns>
        <asp:BoundField DataField="Daily Reports" HeaderText="Daily Report" />
    </Columns>               
</asp:GridView>