DropDownList retain selected value when navigating between pages

Question

User-1797368610 posted

I have DropDownLists on my page to select "Year" and when i am selecting the drop down value its displaying information into gridview.  I am binding data in Page_Load event when (Not Page.IsPostBack). Users will select Year from the DropDownLists and then will click on view or Edit link from the gridview go to a view/edit page. If they then select to 'Go Back' to the initial page from View/Edit page, the DropDownLists year always reset to the top of their alphabetical list or top value.

Is there any way this can be amended to remember the last values the user entered?

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load        
        If Not IsPostBack() Then
            fillddlyear()
            filldatagriddetail("0", "0")            
        End If       

    End Sub


 Private Sub fillddlyear()
        Dim query As String
        Dim lDataSet As System.Data.DataSet
        Try
            query = " select distinct to_char(maint_end_date,'yyyy') year " & _
           " from maintenance_schedule  " & _
           " order by year "
            lDataSet = PassDataSet("DBTS", query)
            DdL_maintyear.DataSource = lDataSet
            DdL_maintyear.DataTextField = "year"
            DdL_maintyear.DataValueField = "year"
            DdL_maintyear.DataBind()
        Catch ex As Exception
            'Lblexception.Text = ex.Message
        End Try
    End Sub
    Private Sub filldatagriddetail(ByVal memberkey As String, ByVal transcnt As Integer)
        Dim query, projno, bld_id As String
        Dim lDataSet As System.Data.DataSet
        Dim mytable As System.Data.DataTable
        Dim totamt As Decimal = 0
        Dim fnd As Boolean = False
        Dim searchchar As String
        searchchar = ":"   ' Search for ":".
        Try
            
            query = "select rownum num,item_description, decode(vendor_id,null,' ',vendor_id) vendor_id, " & _
            " decode(status,null,' ',status) status, estimated_amount, renewal_type, " & _
            " to_char(maint_end_date,'dd-MON-yyyy') mntdate , to_char(status_date,'dd-MON-yyyy') status_date  " & _
            " from maintenance_schedule " & _
            " where to_char(maint_end_date,'YYYY') = '" & DdL_maintyear.SelectedValue & "'" & _
            " order by item_description "

            lDataSet = PassDataSet("DBTS", query)
            Session("projds") = lDataSet
            mytable = lDataSet.Tables("ResultTable")
            Dim dv As DataView = mytable.DefaultView

            'if the user has elected to sort the gridview
            If Not String.IsNullOrEmpty(Me.SortBy("GVdetail")) Then
                'get the sort expression and apply it to our dataView
                Dim sortExpr As String = Me.SortBy("GVdetail") & " " & IIf(Me.SortDirection("GVdetail") = WebControls.SortDirection.Ascending, "ASC", "DESC").ToString()
                dv.Sort = sortExpr
            End If

            Me.GVdetail.DataSource = dv
            Me.GVdetail.DataBind()
            'Lblexception.Text = " "

        Catch ex As Exception
            If Trim(Mid(ex.Message, 1, 9)) = "ORA-01840" Then
                'Lblexception.Text = "** Please enter a valid date. "
            Else


            End If
        End Try


    End Sub