ASP repeater sorting ItemDataBound - asp.net

Question

I'm having a bit of trouble with ASP Repeaters and trying to sort the data.
So on Page_Load I obtain the datasource as below...
Protected Overloads Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
If Not (Page.IsPostBack) Then
'No need to re-load Occasion because it's done in the PreLoad event
Me.Header.Title = "OCP - " + Occasion.Checklist.name
pnlStatistics.Visible = Not (Occasion.isClosed)
pnlClose.Visible = SecurityHelper.HasRole(SecurityMatchOption.AtLeast, SecurityRole.Manager, _relevantTeam) And Not (Occasion.isClosed)
'initially assume checklist can be closed. any un-signed off task in the item_databound event will disable it.
btnClose.Enabled = True
'Fix Issue 63: rptTask.DataSource = _db.vw_tasklists.Where(Function(o) o.occasionId = Occasion.id).ToList()
rptTask.DataSource = _db.vw_tasklists.Where(Function(o) o.occasionId = Occasion.id).OrderBy(Function(t) t.taskDueDate).ThenBy(Function(t) t.taskDueTime)
However within ItemDataBound we recalculate the task duedate.
Private Sub rptTask_ItemDataBound(sender As Object, e As RepeaterItemEventArgs) Handles rptTask.ItemDataBound
' Get the data relating to this task 'row'
Dim t = CType(e.Item.DataItem, vw_tasklist)
If e.Item.ItemType = ListItemType.Header Then
Dim thDueDate = CType(e.Item.FindControl("thDueDate"), HtmlTableCell)
thDueDate.Visible = Not (Occasion.isClosed)
End If
'securable buttons
If e.Item.ItemType = ListItemType.Item Or e.Item.ItemType = ListItemType.AlternatingItem Then
' Dynamically create a span element named TASKnnnn, which will be referenced from
' 'child page' links back to this page in order to vertically reposition at the selected task
Dim span = New HtmlGenericControl("span")
span.ID = "TASK" & t.taskId
span.ClientIDMode = ClientIDMode.Static ' prevent ASP.NET element ID mangling
e.Item.FindControl("lblTaskName").Parent.Controls.AddAt(0, span) ' hook it into the repeater row
Dim btnSignoff = CType(e.Item.FindControl("btnSignOff"), Button)
Dim btnComment = CType(e.Item.FindControl("btnComment"), Button)
Dim btnAmend = CType(e.Item.FindControl("btnAmend"), Button)
Dim btnView = CType(e.Item.FindControl("btnView"), Button)
Dim lblSoTime = CType(e.Item.FindControl("lblSOTime"), Label)
Dim lblDueDate = CType(e.Item.FindControl("lblDueDate"), Label)
Dim lblTaskId = CType(e.Item.FindControl("lblTaskId"), Label)
Dim lblTaskName = CType(e.Item.FindControl("lblTaskName"), Label)
lblTaskId.Text = CType(t.taskId, String)
lblTaskName.Text = t.taskName
Dim time = (If(t.taskDueTime Is Nothing, New TimeSpan(0, 23, 59, 59), TimeSpan.Parse(t.taskDueTime)))
Dim dueDateTime As DateTime = (Occasion.started.Date + time)
'Setup up due DateTime for Daily Tasks
Select Case DirectCast(t.taskDayTypeId, helpers.Constants.enDayType)
Case helpers.Constants.enDayType.Daily
lblDueDate.Text = dueDateTime.ToString("dd/MM/yyyy HH:mm")
Exit Select
Case Else
'Calculate the actual due date for non-daily tasks
Dim calculator = New Calculator()
Dim calId = t.taskCalendarId
Dim taskMonthDay = "1"
If Not t.taskMonthDayId Is Nothing Then
taskMonthDay = CType(t.taskMonthDayId, String)
End If
Dim monthDay = _db.MonthDays.First(Function(m) m.id = CInt(taskMonthDay))
Dim calendar As Model.Calendar = Nothing
If Not calId is Nothing Then
calendar = _db.Calendars.First(Function(x) calId.Value = x.id)
End If
Dim potDate = calculator.GetActualDueDate(dueDateTime, monthDay.monthDay, t, calendar)
dueDateTime = (potDate.Date + time)
lblDueDate.Text = dueDateTime.ToString("dd/MM/yyyy HH:mm")
Exit Select
End Select
Therefore once the data is displayed in the repeater the sorting is wrong. I need to be able to sort the data after the due date re-calculation. How is this possible?
Thanks

Answer 1

You can to move the ItemDataBound logic up into the original query:
rptTask.DataSource = _db.vw_tasklists.
Where(Function(o) o.occasionId = Occasion.id).
Select(
Function(r)
'Fill in the logic here so the DueProperty has your real Due Date
New With {.Row = r, .DueDate = r.TaskDueDate + r.TaskDueTime}
End Function
OrderBy(Function(t) t.DueDate). ' Now we only need one OrderBy (the time is already included).
Select(Function(r) r.Row) 'But we do want to select back to the original record for the databinding
'And the ToList() was probably NEVER needed or helpful in this situation
Moreover, since this looks like linq-to-sql I might break that up a bit, so we cleanly separate what we expect to execute on the database from what we expect to execute on the web server:
'This runs on the databsae
Dim sqlData = _db.vw_tasklists.
Where(Function(o) o.occasionId = Occasion.id)
'This runs on the web server
rptTask.DataSource = sqlData.
Select(
Function(r)
'Fill in the logic here so the DueProperty has your real Due Date
New With {.Row = r, .DueDate = r.TaskDueDate + r.TaskDueTime}
End Function
OrderBy(Function(t) t.DueDate). ' Now we only need one OrderBy (the time is already included).
Select(Function(r) r.Row) 'But we do want to select back to the original record for the databinding
'And the ToList() was probably NEVER needed or helpful in this situation
Of course, you'll get the best results if you start putting information into the database such that you can effectively sort your data correctly there at the outset.