Chapter 5 Question

jltscaa · December 2nd, 2009, 07:55 AM

Built the example code in Chp 5 fine but after running it and attempting to use the "Delete Customer" button, I get an ArgumentException with the message "Cannot remove the specified item because it was not found in the specified Collection." In viewing the contents of "objCustomers" or "oldCustomer" is lists "Nothing" for the fields. Anyone else have an issue with this or have an idea of what my issue is likely caused by? Seems to me that during the SelectedCustomer property, nothing is getting returned.

Driving me mad!

Thearon · December 2nd, 2009, 04:18 PM

Have you downloaded the code for the book and compared the code for this exercise to your code?

Give that a try. It sounds like you might have missed a step somewhere along the way.

Thearon

jltscaa · December 3rd, 2009, 06:46 AM

Don't know how - maybe too early in morning - missed the line for "objCustomers.Add(objNewCustomers)". Thanks for the suggestion - loving the book!

peebeedee · February 28th, 2010, 11:51 PM

Quote:

Originally Posted by jltscaa

Built the example code in Chp 5 fine but after running it and attempting to use the "Delete Customer" button, I get an ArgumentException with the message "Cannot remove the specified item because it was not found in the specified Collection." In viewing the contents of "objCustomers" or "oldCustomer" is lists "Nothing" for the fields. Anyone else have an issue with this or have an idea of what my issue is likely caused by? Seems to me that during the SelectedCustomer property, nothing is getting returned.

Driving me mad!

I had a similar experience and came to the same conclusion. I was able to get things to work by adding an Item property with an index parameter to the CustomerCollection Class.

Code:

Default Public Property Item(ByVal index As Integer) As Customer
        Get
            Return CType(List(index), Customer)
        End Get
        Set(ByVal value As Customer)
            List(index) = value
        End Set
    End Property

I changed the SelectedCustomer property as follows:

Code:

 Public ReadOnly Property SelectedCustomer() As Customer
        Get
            If lstCustomers.SelectedIndex <> -1 Then
                Return objCustomers.Item(lstCustomers.SelectedIndex)
            End If

        End Get

I was unable to detect any difference between my code, before these changes, and the downloaded code.

I hope this helps.

peebeedee · March 1st, 2010, 02:18 AM

My apologies. I seem to have skipped two full pages. The code it took quite a bit of time in help to figure out was right there in the book. I guess it was too early in the morning for me, too.

solacunis.h · March 1st, 2010, 11:06 AM

Question.
With XP comes Microsoft Works, there is a section called Data Base.
If you fill the data base with only the stuff you need to complete a project.
How do you connect to it considering it is internal, my Vis B is on the same machine.
This is self contained and not involving SQL etc.

cheers.

jbinarao · May 18th, 2010, 08:39 PM

Quote:

Originally Posted by solacunis.h

Question.
With XP comes Microsoft Works, there is a section called Data Base.
If you fill the data base with only the stuff you need to complete a project.
How do you connect to it considering it is internal, my Vis B is on the same machine.
This is self contained and not involving SQL etc.

cheers.

Regarding connecting with a Microsoft Works Database (*.wdb), there isn't really a clean way to do this. I tried playing with this some time ago, and the challenge I ran into was that I couldn't find a database driver or a data provider for Works database files.

Just a few thoughts...

I understand you don't have Access, so what you might try and do is export the *.wdb file as a flat *.csv file, and then import that into SQL Express (free).

You can create an ODBC connection to a *.csv or *.txt file by creating an ODBC connection with the Microsoft Text Driver. With that, there is a System.Data.ODBC database connection method in Visual Studio, which you could use to then tap into that *.csv file.

If you plan on using smaller databases, it might be worth the investment in Access, or maybe better, a Microsoft TechNet subscription (Windows and Office), or a pricier an MSDN subscription (Windows, Office, Visual Studio).

A bit more complicated, and certainly way more involved: you can create a blank Access *.mdb file when trying to create an Access ODBC connection within Windows (Control Panel, Administrative Tools, Data Sources, System DSN, Add, Microsoft Access Driver, Finish, Create...). If you created a blank Access file, you would then need to build an application in Visual Studio to populate the database (I know, ouch!).