Custom Calendar Which Can Return Null dates

Hiya,

I hope someone can help me with this.

From what i can see there doesn't seem to be a way to show a Calendar control with a null date.

In my app have a Datalist where there are a number of labels. 2 of these labels are for Start_Date and End_Date. It is possible that there is not a date shown in these labels if there is no date in the database. Upon selecting the edit button on a given record i go to the edititemtemplate section where most of the labels are changed to text boxes. The two date labels however are change for the calendar control. If i want to enter a null date there seems to be no possible way to do this (Although i probably just haven't found it yet).

Firstly, is there a way i can select a null date?

if not could some one help me with some advice on how to customise the calender control, possibly to include a check box that can be selected for null.

I haven't looked into customizing server controls yet and think this would be a good example to do this with.

All help is greatly recieved and appreciated.

Thanks in advance.

Ok.

Just an update. I think from what i've read elsewhere i can create a composite control with both a calendar control and a check box control. i have the following code which as far as i can make out is correct but isn't working correctly:

Code:

---

Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.ComponentModel
Imports System

Namespace myCalendar

    Public Class nullCalendar

        Inherits System.Web.UI.WebControls.Calendar : Implements INamingContainer

        Protected Overrides Sub CreateChildControls()

            Dim cal As New Calendar
            Dim cb As New CheckBox

            Me.Controls.Add(cal)
            Me.Controls.Add(New LiteralControl("<P>"))
            Me.Controls.Add(cb)

        End Sub

    End Class

End Namespace

---

when i add the dll that is created to my app and then drag the control on to the page i get an error stating:

'myCalendar.myCalendar.nullCalendar' does not allow child controls.

Not to sure why this is happening as i thought overriding the createchildcontrols would stop this error.

Does anyone have an idea as to what i may have done wrong.

Cheers

OK,

Solved this problem myself as well.

i was inheriting a "calendar" as apposed to just "control".

This part's now working and the composite control is working basically with the following code.

Code:

---

Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.ComponentModel
Imports System

Namespace myCalendar

    Public Class nullCalendar

        Inherits Control
        Implements INamingContainer

        Dim cal As New Calendar
        Dim cb As New CheckBox

        Public Property dateVal() As Object

            Get

                Select Case cb.Checked
                    Case True : Return DBNull.Value
                    Case False
                        If cal.SelectedDate = "" Then
                            cal.SelectedDate = Today
                        End If

                        Return cal.SelectedDate
                End Select

            End Get

            Set(ByVal Value As Object)

                If Value = "" Then
                    cb.Checked = True
                    cal.Enabled = False
                Else
                    cb.Checked = False
                    cal.SelectedDate = Value
                    cal.VisibleDate = Value
                End If

            End Set

        End Property

        Sub cbChange(ByVal s As Object, ByVal e As EventArgs)

            Select Case cb.Checked
                Case True : cal.Enabled = False
                Case False : cal.Enabled = True
            End Select

        End Sub

        Protected Overrides Sub CreateChildControls()

            Me.Controls.Add(cal)
            Me.Controls.Add(New LiteralControl("<P>"))
            Me.Controls.Add(cb)
            cb.Text = "No Date Required"
            cb.AutoPostBack = True

            AddHandler cb.CheckedChanged, AddressOf cbChange

        End Sub

    End Class

End Namespace

---

I still have one more problem with the custom control. When i have two on the same page and a post back occurs from one control, the other loses its settings.

Can anyone help with how to keep the settings after postbacks.

Thanks