I'm writing a custom user control for my asp.net site, for storing datetimes. It has two properties:
Private _includeTime As Boolean
Private _value As DateTime = Nothing
Public Property IncludeTime() As Boolean
Get
Return _includeTime
End Get
Set(ByVal value As Boolean)
_includeTime = value
End Set
End Property
Public Property SelectedDateTime() As DateTime
Get
Try
_value = DateTime.Parse(txtDate.Text)
If IncludeTime Then
_value.AddHours(Short.Parse(txtHour.Text))
_value.AddMinutes(Short.Parse(txtMinute.Text))
_value.AddSeconds(Short.Parse(txtSecond.Text))
End If
Catch ex As Exception
_value = Nothing
End Try
Return _value
End Get
Set(ByVal value As DateTime)
_value = value
End Set
End Property
I call my custom control in this way:
<my:DateTimeInput runat="server" includetime="true" ID="txtWhen" />
This sets the includetime property correctly.
In my backend code I also do this on page_load:
txtWhen.SelectedDateTime = now
When I step through with the debugger, I see that the property gets set, BUT when the page_load of the control itself loads, the property value is reset to nothing!
The page_load of the control:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
lbltime.Visible = IncludeTime
If SelectedDateTime().CompareTo(Nothing) > 0 Then
txtDate.Text = SelectedDateTime.Date.ToShortDateString()
txtHour.Text = SelectedDateTime.Hour.ToString("D2")
txtMinute.Text = SelectedDateTime.Minute.ToString("D2")
txtSecond.Text = SelectedDateTime.Second.ToString("D2")
End If
End Sub
Any ideas why this property loses its value?
Best Answer
Your control's Page_Load method uses the SelectedDateTime property rather than the underlying _value field.
The Get method for the SelectedDateTime property rebuilds _value from the contents of txtDate (and txtHour etc...). So regardless of what you set _value to, the SelectedDateTime property will return what was in the text boxes, which I presume is nothing because the page is only just loading.
I suggest you change
to