[RESOLVED] [2005] User Control Question

[s2002h69]

Hello,

I put together a user control with two date pickers and labels. I am to set the labels text property and get the number of days between the date ranges. I have the code to do this, but when I test the control, the labels do not have the new text property. I haven't tested the date range portion yet. I have followed the steps in the text book on building the solution so that the control is available when using the form. Could someone let me know what I'm doing wrong with setting the label text? Here is my control code:

Public Class DateRange
 
    Public WriteOnly Property PickUp() As String
        Set(ByVal value As String)
            Label1.Text = "PickUp Day"
        End Set
    End Property
 
    Public WriteOnly Property DropOff() As String
        Set(ByVal value As String)
            Label2.Text = "DropOff Day"
        End Set
    End Property
 
    Public ReadOnly Property GetDays() As String
        Get
            'Declare variables 
            Dim DayCount As Integer
 
            'Determine number of days
            DayCount = CInt((DateDiff(DateInterval.Day, DateTimePicker1.Value, DateTimePicker2.Value)))
 
            Return CStr(DayCount)
 
        End Get
    End Property
End Class

Thanks

[jmcilhinney]

You're setting the Text of the Labels to a predefined string no matter what the caller passes. The 'value' argument contains the string the the caller is trying to set, so you have to assing that to the Label's Text property:

Public WriteOnly Property PickUp() As String
        Set(ByVal value As String)
            Label1.Text = [U]value[/U]
        End Set
    End Property
 
    Public WriteOnly Property DropOff() As String
        Set(ByVal value As String)
            Label2.Text = [U]value[/U]
        End Set
    End Property

[s2002h69]

Hello,

Sorry, I'm a little confused. Where does "Value" come from? Do I set this through the controls property window (the label text field) for each label then use the Get and Set portion in the public property? I don't see where else "Value" would come from.

Thanks

[jmcilhinney]

You don't do anything. It's is the parameter passed to the Set method:

Public WriteOnly Property PickUp() As String
        Set(ByVal [U]value[/U] As String)
            Label1.Text = [U]value[/U]
        End Set
    End Property

When you use a property you are implicitly calling either the Get or Set method from the property definition. Your properties are WriteOnly so they only have a setter. When someone assigns a value to your property like this:

myDateRange.PickUp = SomeValue

They are implicitly calling this method:

Set(ByVal value As String)
            Label1.Text = value
        End Set

and SomeValue is passed as the 'value' parameter.

[s2002h69]

Ok, I understand now, I think. I use the generic "Value" in the control, then when I use the control on the form I set the value for the label text by using:

myDateRange.PickUp = SomeValue

Thank you very much!

[s2002h69]

Just got it to work. Thanks again. I'm sure I'll have more control questions in the near future.