How do I get the object to perform the method on itself? 1

[AndyInNC]

Well, I've got this object based on clsAttachment. This class reads from the Attachments table in the database and tracks the links to the files stored on the server. One of the data fields is IsMissing. If the database says the file is there, but it's really not, IsMissing needs to be set to TRUE.

So I created a method called SetAsMissing().

Here's the calling code:
[tt]
Dim oAttachment As New clsAttachment(ID)
[/tt]
This populates the object so everything is there (LinkName, ID, Title, etc). It seems really dumb to add parameters to SetAsMissing(ID As Integer) when I already have the ID. How can I write it as
[tt] oAttachment.SetAsMissing[/tt]
and not
[tt] oAttachment.SetAsMissing(ID)[/tt] ?

Thanks.

 

[SkipVought]

Hi,

There are several IS FUNCTIONS in MS languages. IsMissing is on of them. I would AVOID using IsMissing, unless you are using this function.

If this is you own field, as it appears to be, your logic must assign the value accordingly. HOWEVER, storing such a value in a database is suspect, as it is only as good at the moment it is loaded. At some subsequent time, your file may go away and the data will be 'out of synch!'

Skip,

_{Just traded in my old subtlety...
for a NUANCE!}

 

[RiverGuy]

You don't need a SetAsMissing method. Consider the code below:

Public Class clsAttachment
    Private mID As Integer
    Private mIsMissing As Boolean = False

    Sub New(ByVal ID As Integer)
        Me.mID = ID
    End Sub

    Public Property IsMissing()
        Get
            Return Me.mIsMissing
        End Get
        Set(ByVal value)
            Me.mIsMissing = value
        End Set
    End Property
End Class

Your constructor takes the ID and assigns it to the mID class-level variable. Looking at your example, I assume you also have something like this.

Similarly, I have created the mIsMissing class-level variable which is exposed via the IsMissing property. This property takes the place of your SetAsMissing method. You do not need to pass in the ID -- it's already part of the object instance.

Now, you could go a couple of ways with this. You could create a .Save method in your class which would save all of your "fields" back to the database. Or, you could create a method to update your database table for the IsMissing value, and call that method in the Set portion of your property. I would advise against this because it could make for a poor user interface experience due to network latency.

 

[AndyInNC]

Thanks for the input.

Skip, good point about the IsMissing name. I'll fix that.

RiverGuy, you're dead on. That's my code exactly except, in the constructor, all the properties of the object are populated. Yes, flagging the record with a SetAsMissing() function could cause response problems for the user, but we expect the circumstances to be so rare the impact will be minimal. At this point in the UI, all the user is doing is looking at the attachment -- no other saving going on -- so if it's not there, we want to flag it and keep on going. The user is in no position to solve it anyway.

What you included in your sample is
[tt]
Me.mID = ID
[/tt]
I didn't include Me, but when I added that, it found the reference. I need to read-up on Me inside a class.

Thanks for the help.