Gridview not maintaining sort after paging

[Cineno]

All the help I've been able to find from similar posts regarding this issue isn't working for how I set up my GridView.

I've gotten my Gridview to have dynamically created columns, and was able to get sorting to work on it. My paging works also, but if I sort first and then go to another page, it loses the sort.

What do I need to change in my Paging method to remember the sort?

Here is the code for the GridView:

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


    If Not IsPostBack Then

        Dim curLastName As New BoundField
        curLastName.HeaderText = "Last Name"
        curLastName.DataField = "LastName"
        curLastName.SortExpression = "LastName"
        GridView1.Columns.Insert(0, curLastName)

        Dim curFirstName As New BoundField
        curFirstName.HeaderText = "First Name"
        curFirstName.DataField = "FirstName"
        curFirstName.SortExpression = "FirstName"
        GridView1.Columns.Insert(1, curFirstName)

        Dim dt As DataTable = GetData().Tables(0)

        Dim dv As New DataView(dt)



        GridView1.DataSource = dv

        GridView1.DataBind()
    End If
End Sub

Private Function GetData() As DataSet

    Dim connectionstr As String

    connectionstr = ConfigurationManager.ConnectionStrings("dbConnectionString").ConnectionString.ToString()

    Dim myConnection As New SqlConnection(connectionstr)

    Dim ad As New SqlDataAdapter("SELECT * FROM EmployeeList where lastname like 'wil%'", myConnection)

    Dim ds As New DataSet()

    ad.Fill(ds)

    Return ds

End Function

Public Property GridViewSortDirection() As SortDirection


    Get


        If ViewState("sortDirection") Is Nothing Then

            ViewState("sortDirection") = SortDirection.Ascending
        End If


        Return DirectCast(ViewState("sortDirection"), SortDirection)
    End Get

    Set(ByVal value As SortDirection)
        ViewState("sortDirection") = value
    End Set
End Property


Protected Sub GridView1_Sorting(ByVal sender As Object, ByVal e As GridViewSortEventArgs)


    Dim sortExpression As String = e.SortExpression

    If GridViewSortDirection = SortDirection.Ascending Then


        GridViewSortDirection = SortDirection.Descending


        SortGridView(sortExpression, "DESC")
    Else



        GridViewSortDirection = SortDirection.Ascending


        SortGridView(sortExpression, "ASC")
    End If

End Sub

Private Sub SortGridView(ByVal sortExpression As String, ByVal direction As String)

    Dim dt As DataTable = GetData().Tables(0)

    Dim dv As New DataView(dt)

    dv.Sort = sortExpression & " " & direction

    GridView1.DataSource = dv

    GridView1.DataBind()

End Sub



Protected Sub GridView1_PageIndexChanging(ByVal sender As [Object], ByVal e As GridViewPageEventArgs)


    GridView1.PageIndex = e.NewPageIndex


    Dim dt As DataTable = GetData().Tables(0)

    Dim dv As New DataView(dt)



    GridView1.DataSource = dv

    GridView1.DataBind()



End Sub

The sorting and paging work, I'm just not sure what I have to change in my paging method to remember the sort. Thanks for any help!

 

[Rhys666]

As you're fetching the data every time the sort is lost. Either capture the fact that a sort has been applied, what it is and re-apply it when changing pages, or cache the data behind the grid and update the cached data with it's sorted equivalent when a sort is applied. That when when the page is changed you don't need to re-fetch the data from source, you need to r5e-fetch it from the cache.

Rhys

"Technological progress is like an axe in the hands of a pathological criminal"
"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe"
Albert Einstein

 

[jbenson001]

Make sure viewstate is enabled on the gridview

 

[Cineno]

Thank you both. I got it working now. I appreciate the help!