В момента работя върху някакъв код, който се грижи за сортирането и странирането на данни в изглед на мрежата. Сега се опитвам да внедря стрелка за сортиране (стрелки нагоре/надолу до заглавките на колоните), но нямам успех. Кодът за прилагане на стрелките за сортиране се намира в подпрограмата *GridView1_RowCreated*. Точно сега, когато стартирам кода, изобщо не виждам стрелките за сортиране. Проблемният ред е следният: „If tblAdministrators.SortExpression = lnk.CommandArgument Then“ Не мога да разбера какво не е наред с този ред. Винаги е False, поради което стрелките не се показват.
Private Function GetData(sort As SortDirection) As Data.DataView
Dim connection As OracleDBConnect = DAL.GetOracleDBConnection()
Dim request As OracleDBRequest = Nothing
Dim result As OracleDBResult = Nothing
Dim trace As OracleDBChronoTrace = Nothing
Dim status As DBStatus
Dim sb As New StringBuilder
Dim dv As DataView
With sb
.Append("SELECT * FROM USERS")
End With
request = New OracleDBRequest(sb.ToString, CommandType.Text)
status = connection.Execute(request, result, trace)
dv = New DataView(result.DataSet.Tables(0))
If (ViewState("sortExp") IsNot Nothing) Then
dv = New Data.DataView(result.DataSet.Tables(0))
If (GridViewSortDirection = SortDirection.Ascending) Then
GridViewSortDirection = SortDirection.Descending
dv.Sort = CType(ViewState("sortExp").ToString() & DESCENDING, String)
Else
GridViewSortDirection = SortDirection.Ascending
dv.Sort = CType(ViewState("sortExp").ToString() & ASCENDING, String)
End If
Else
dv = result.DataSet.Tables(0).DefaultView
End If
Return dv
End Function
Public Property GridViewSortDirection() As SortDirection
Get
If ViewState("sortDir") Is Nothing Then
ViewState("sortDir") = SortDirection.Ascending
End If
Return CType(ViewState("sortDir"), SortDirection)
End Get
Set(ByVal value As SortDirection)
ViewState("sortDir") = value
End Set
End Property
Protected Sub GridView1_PageIndexChanging(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewPageEventArgs) Handles tblAdministrators.PageIndexChanging
tblAdministrators.PageIndex = e.NewPageIndex
GridViewSortDirection = If(GridViewSortDirection = SortDirection.Descending, SortDirection.Ascending, SortDirection.Descending)
tblAdministrators.DataSource = GetData(GridViewSortDirection)
tblAdministrators.DataBind()
End Sub
Protected Sub GridView1_Sorting(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewSortEventArgs) Handles tblAdministrators.Sorting
ViewState("sortExp") = e.SortExpression
tblAdministrators.DataSource = GetData(GridViewSortDirection)
tblAdministrators.DataBind()
End Sub
Protected Sub GridView1_RowCreated(sender As Object, e As GridViewRowEventArgs) Handles tblAdministrators.RowCreated
If e.Row.RowType = DataControlRowType.Header Then
For Each tc As TableCell In e.Row.Cells
If tc.HasControls() Then
Dim lnk As LinkButton = DirectCast(tc.Controls(0), LinkButton)
If lnk IsNot Nothing Then
Dim img As New System.Web.UI.WebControls.Image()
img.ImageUrl = "/images/" & (If(GridViewSortDirection = SortDirection.Ascending, "asc", "desc")) & ".gif"
If tblAdministrators.SortExpression = lnk.CommandArgument Then
tc.Controls.Add(New LiteralControl(" "))
tc.Controls.Add(img)
End If
End If
End If
Next
End If
End Sub
ASPX код:
<asp:GridView ID="tblAdministrators" runat="server" AutoGenerateColumns="false" EmptyDataText="No records found" PageSize="25" AllowPaging="True" AllowSorting="True" OnRowCreated="GridView1_RowCreated">
<Columns>
<asp:BoundField HeaderText="Name" DataField="Name" SortExpression="NAME"></asp:BoundField>
</Columns>
<Columns>
<asp:BoundField HeaderText="City" DataField="City" SortExpression="CITY"></asp:BoundField>
</Columns>
</asp:GridView>
