PRB: DataEnvironment: DataReport Moves Form To EOF

• Microsoft Visual Basic Enterprise Edition for Windows, version 6.0

SYMPTOMS

When you have a DataReport and Form with controls bound to the same DataEnvironment, opening the report causes the form to be blank.

CAUSE

When the report steps through the records, it is moving the current position for the DataEnvironment and stops when it reaches EOF (end-of- file). This becomes the current position for the form, which displays blank fields.

RESOLUTION

• Open a second copy of the DataEnvironment in code and set the DataReport's DataSource property to this variable instead of the global DataEnvironment object.


-or-


• Reset the record pointer from a timer event.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a new Visual Basic EXE project and add a form (Form1), DataEnvironment (DataEnvironment1), and DataReport (DataReport1).



2. In the DataEnvironment designer, add a connection (Connection1) to a database, such as Microsoft SQL Server.



3. Off the connection, create a command (Command1) that selects records from a table, such as SELECT * FROM Authors.



4. Save the DataEnvironment.



5. In the DataReport designer, set the following properties:

   
         DataSource: DataEnvironment1
         DataMember: Command1 




6. Add some fields from the table and save the report.



7. Add some textboxes to the form and set the following properties:

   
         DataSource: DataEnvironment1
         DataMember: Command1
         DataField: choose from the fields in the table 




8. Run the project. The form opens and displays the first record in the table.



9. Close the form and add the following code to it:

   
         Option Explicit
   
         Sub Form_Load ()
           DataReport1.Show
         End Sub 




10. Run the project again. The DataReport opens and shows the records. When you switch to the form, it is blank. The DataReport has moved the cursor to the EOF position, so the form has not record to display.

Workaround 1

1. Modify the form code as follows:

   
         Option Explicit
   
         Sub Form_Load ()
           Dim de As DataEnvironment1
           Set de = New DataEnvironment1
           Set DataReport1.DataSource = de
            DataReport1.Show
         End Sub 




2. Run the project. The form is now correctly positioned to the first record because the DataReport is using a different instance of the DataEnvironment.

Workaround 2

1. Add a Timer (Timer1) to the form and set the Interval property to 0.



2. Modify the form code as follows:

   
         Option Explicit
   
         Sub Form_Load ()
           DataReport1.Show
           Timer1.Interval = 1
         End Sub
   
         Sub Timer1_Timer ()
           DataEnvironment1.rsCommand1.MoveFirst
           Timer1.Interval = 0
         End Sub 




3. Run the project. The form is now correctly positioned to the first record. The timer event does not fire until the DataReport has finished stepping through the records and so safely resets the record pointer. This does not affect the DataReport.

Additional query words: kbDSupport kbdse kbvbp600 kbVBp kbDataBinding

Keywords : kbGrpVBDB
Version :
Platform : WINDOWS
Issue type : kbprb