10: ADO.NET in Visual Basic .NET

Printing QR Code 2d barcode in Visual Basic .NET 10: ADO.NET

2. The second step asks, Which data connection should your application use to connect to the database We ll have to create a new connection for the Library database we designed way back in 4. Click the New Connection button. 3. The Choose Data Source dialog appears. Select Microsoft SQL Server from the Data source list, and then click the Continue button. If you have accessed this dialog before and checked the Always use this selection field, it s possible that this dialog will not appear at all. 4. The Add Connection dialog appears to collect the details of the new connection. If the Data source field contains something other than Microsoft SQL Server, click the Change button to alter the connection type using the dialog mentioned in step 3. 5. Back on the Add Connection form fill in the Server name field with the name of your SQL Server instance. Hopefully, this drop-down list already has the instances listed, but if not, you ll have to enter it yourself. The default for SQL Server Express is the name of your computer, with \SQLEXPRESS attached. If your computer name is MYSYSTEM, the instance name would be MYSYSTEM\SQLEXPRESS. 6. Configure your authentication settings in the Log on to the server section. I used standard Windows authentication, but it depends on how you set up the database in 4. 7. In the Connect to a database section, either select or type in Library for the database name. 8. Click the Test Connection button to make sure it all works. When you re finished, click the OK button to create the new connection. 9. OK, we re back on the Data Source Configuration Wizard form. The connection we just created should now appear in the list, as shown in Figure 10-3. Click Next.

10. The next panel asks whether this data source should become part of the configurable settings for this project. We ll get into the settings features of Visual Basic in 14. For now, just accept the default and click Next. 11. We re almost there. Only 27 more steps to go! Just kidding. This is the last step in creating the data source. The final panel shows a list of the data-generating features in the Library database. Open the Tables branch and select Activity, as shown in Figure 10-4. Then click Finish. Check out the Data Sources panel shown in Figure 10-5. It includes the new LibraryDataSet data source with its link to the Activity table.

So, what is this data source anyway It is simply a link to some portion of your database, wrapped up in a typical .NET object. Now that it s part of your project, you can use it to access the data in the Activity table through your project s code, or by drag-and-drop. In the Data Sources panel, you will find that the Activity entry is actually a drop-down list. Select Details from the list, as I ve done in Figure 10-6. (The surface of Form1 must be displayed for this to work.) Finally, drag-and-drop the Activity entry onto the surface of Form1. When you let go, Visual Studio will add a set of controls to the form, plus a few more non-userinterface controls just below the form (see Figure 10-7).

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By just dragging-and-dropping, Visual Studio added all the necessary controls and links to turn your form into a turbo-charged Activity table editor. Try it now by pressing the F5 key. In the running program, you can use the Microsoft Access-style record access VCR control to move between the records in the Activity table. You can also modify the values of each record, add new records, or delete existing records (but please restore things back to their original state when you are done; we ll need all the original records later). Talk about power! Talk about simplicity! Talk about unemployment lines! Who needs highly paid programmers like us when Visual Studio can do this for you