GridView isn't paging or sorting when inside a user control

My Gridview won't page or sort. By this I mean that the data in the GridView doesn't change when I try to sort by a column or when I try to page through the GridView.

I have it inside an UpdatePanel on a user control (.ascx). The code below works fine when I try it outside of the user control.

Here's my code:

    <asp:GridView runat="server" ID="grdStats" AutoGenerateColumns="false" Width="100%" AllowSorting="true"
        AllowPaging="true" PageSize="20" PagerSettings-Mode="NumericFirstLast" PagerSettings-Position="TopAndBottom">
        <Columns>
            <asp:BoundField DataField="campaignname" HeaderText="Campaign Name" SortExpression="campaignname" />
            <asp:BoundField DataField="site_name" HeaderText="Outlet" SortExpression="site_name" />
            <asp:BoundField DataField="filename" HeaderText="Media" SortExpression="filename" />
            <asp:BoundField DataField="playinterval" HeaderText="Play Interval" SortExpression="playinterval" />
        </Columns>
    </asp:GridView>

Here's the backend:

Protected Sub grdStats_PageIndexChanging(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewPageEventArgs) Handles grdStats.PageIndexChanging
    grdStats.PageIndex = e.NewPageIndex
    GetCampaignData()
End Sub

Protected Sub grdStats_Sorting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewSortEventArgs) Handles grdStats.Sorting

    If e.SortExpression = ViewState("sortExpr") Then
        ViewState("sortExpr") = e.SortExpression & " desc"
    Else
        ViewState("sortExpr") = e.SortExpression
    End If

    GetCampaignData()

End Sub

' ######## POPULATE DATA #########

Private Sub GetCampaignData(Optional ByVal CompanyID As Integer = 0)
    Dim sql As String = Nothing

    ' Check user access level.
    If Session("userlevel") = 1 Then
        ' Current user is admin.

        ' If a company has been filtered, get it's data, else, get all campaign data.
        If CompanyID <> 0 Then
            sql = "SELECT" & vbCrLf & _
            "   a.campaignid," & vbCrLf & _
            "   a.companyid," & vbCrLf & _
            "   a.campaignname," & vbCrLf & _
            "   a.filename," & vbCrLf & _
            "   startdate," & vbCrLf & _
            "   enddate," & vbCrLf & _
            "   a.playinterval," & vbCrLf & _
            "   a.ActiveStatus," & vbCrLf & _
            "   b.*," & vbCrLf & _
            "   (SELECT COUNT(*)" & vbCrLf & _
            "       FROM campaignstats AS c" & vbCrLf & _
            "       WHERE DAY(date_played) = DAY(CURRENT_DATE)" & vbCrLf & _
            "       AND c.campaignid = a.campaignid" & vbCrLf & _
            "   ) AS today," & vbCrLf & _
            "   (SELECT COUNT(*)" & vbCrLf & _
            "       FROM campaignstats AS d" & vbCrLf & _
            "       WHERE date_played > CURRENT_DATE - INTERVAL 7 DAY" & vbCrLf & _
            "       AND d.campaignid = a.campaignid" & vbCrLf & _
            "   ) AS past_week," & vbCrLf & _
            "   (SELECT COUNT(*)" & vbCrLf & _
            "       FROM campaignstats AS e" & vbCrLf & _
            "       WHERE e.campaignid = a.campaignid" & vbCrLf & _
            "   ) AS playcount" & vbCrLf & _
            "FROM campaigns AS a" & vbCrLf & _
            "INNER JOIN companies AS b ON a.companyid = b.companyid" & vbCrLf & _
            "WHERE a.ActiveStatus = 1" & vbCrLf & _
            "AND a.companyid = " & CompanyID

        Else
            sql = "SELECT" & vbCrLf & _
            "   a.campaignid," & vbCrLf & _
            "   a.companyid," & vbCrLf & _
            "   a.campaignname," & vbCrLf & _
            "   a.filename," & vbCrLf & _
            "   startdate," & vbCrLf & _
            "   enddate," & vbCrLf & _
            "   a.playinterval," & vbCrLf & _
            "   a.ActiveStatus," & vbCrLf & _
            "   b.*," & vbCrLf & _
            "   (SELECT COUNT(*)" & vbCrLf & _
            "       FROM campaignstats AS c" & vbCrLf & _
            "       WHERE DAY(date_played) = DAY(CURRENT_DATE)" & vbCrLf & _
            "       AND c.campaignid = a.campaignid" & vbCrLf & _
            "   ) AS today," & vbCrLf & _
            "   (SELECT COUNT(*)" & vbCrLf & _
            "       FROM campaignstats AS d" & vbCrLf & _
            "       WHERE date_played > CURRENT_DATE - INTERVAL 7 DAY" & vbCrLf & _
            "       AND d.campaignid = a.campaignid" & vbCrLf & _
            "   ) AS past_week," & vbCrLf & _
            "   (SELECT COUNT(*)" & vbCrLf & _
            "       FROM campaignstats AS e" & vbCrLf & _
            "       WHERE e.campaignid = a.campaignid" & vbCrLf & _
            "   ) AS playcount" & vbCrLf & _
            "FROM campaigns AS a" & vbCrLf & _
            "INNER JOIN companies AS b ON a.companyid = b.companyid" & vbCrLf & _
            "WHERE a.ActiveStatus = 1"


        End If
    Else
        ' User is not an admin. 
        sql = "SELECT" & vbCrLf & _
        "   a.campaignid," & vbCrLf & _
        "   a.companyid," & vbCrLf & _
        "   a.campaignname," & vbCrLf & _
        "   a.filename," & vbCrLf & _
        "   startdate," & vbCrLf & _
        "   enddate," & vbCrLf & _
        "   a.playinterval," & vbCrLf & _
        "   a.ActiveStatus," & vbCrLf & _
        "   b.*," & vbCrLf & _
        "   (SELECT COUNT(*)" & vbCrLf & _
        "       FROM campaignstats AS c" & vbCrLf & _
        "       WHERE DAY(date_played) = DAY(CURRENT_DATE)" & vbCrLf & _
        "       AND c.campaignid = a.campaignid" & vbCrLf & _
        "   ) AS today," & vbCrLf & _
        "   (SELECT COUNT(*)" & vbCrLf & _
        "       FROM campaignstats AS d" & vbCrLf & _
        "       WHERE date_played > CURRENT_DATE - INTERVAL 7 DAY" & vbCrLf & _
        "       AND d.campaignid = a.campaignid" & vbCrLf & _
        "   ) AS past_week," & vbCrLf & _
        "   (SELECT COUNT(*)" & vbCrLf & _
        "       FROM campaignstats AS e" & vbCrLf & _
        "       WHERE e.campaignid = a.campaignid" & vbCrLf & _
        "   ) AS playcount" & vbCrLf & _
        "FROM campaigns AS a" & vbCrLf & _
        "INNER JOIN companies AS b ON a.companyid = b.companyid" & vbCrLf & _
        "WHERE a.ActiveStatus = 1" & vbCrLf & _
        "AND a.companyid = " & CInt(Session("companyid"))
    End If

    grdCampaigns.DataSource = get_data(sql)
    grdCampaigns.DataBind()

    For i As Integer = 0 To grdCampaigns.Rows.Count - 1
        grdCampaigns.Rows(i).Cells(2).Text = Microsoft.VisualBasic.Left(grdCampaigns.Rows(i).Cells(2).Text, 10)
        grdCampaigns.Rows(i).Cells(3).Text = Microsoft.VisualBasic.Left(grdCampaigns.Rows(i).Cells(3).Text, 10)
    Next
End Sub

Public Function get_data(ByVal SQLStatement As String) As DataView

    'Populates the datatable
    Dim dt As Data.DataTable

    dt = db.GetDataTable(SQLStatement)

    Dim dv As System.Data.DataView = New System.Data.DataView(dt)

    If Not ViewState("sortExpr") Is Nothing Then
        dv.Sort = ViewState("sortExpr")
    Else
        dv = dt.DefaultView
    End If

    Session("dv5") = dv
    Return dv
End Function

Any help would be greatly appreciated.

My apologies the code I pasted in the question, although correct for it's purpose, was not the right code relevant to this question. That said, I'd like to thank you Icarus for taking the time to look over my code.

The paging/sorting works. What I did to fix it was to replace the call to GetCampaignData() within the PageIndexChanging and Sorting event handlers to the SQL code and data binding methods required to give me the results I needed.