PRB: Datacombo Returns -2147217848 (80040e4e) Change Canceled

ID: Q229272

The information in this article applies to:

Microsoft Visual Basic Professional and Enterprise Editions for Windows, version 6.0

SYMPTOMS

When using a DataCombo control, if the DataField property of the DataCombo is bound to a numeric data type a problem may occur under the following circumstances:

The user clicks the combo box and moves the mouse over the entries in the drop-down portion of the combo box but does NOT choose an item from the list. The user then clicks another control so that the DataCombo loses focus and an attempt is made to update the underlying data source specified in the DataField property.

This action fails because the Text property of the combo is an empty string (non-numeric) and the bound field is a numeric type. In this case the following error message is returned:

-2147217848 (80040e4e) The change was canceled during notification; no columns are changed.

RESOLUTION

To work around this error check the Text property of the Datacombo. If it is blank, cancel the update to the underlying records. This work around is demonstrated in the code sample in the MORE INFORMATION section.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

The following steps will reproduce this problem:

Create a new Visual Basic Standard EXE project.

Choose Components from the Project menu and then add a reference to Microsoft Datalist Controls 6.0 (OLEDB).

Add a regular text box and a Datacombo to the default form.

Paste the following code into the default form:


Private rsRowsource As ADODB.Recordset
Private rsDataSource As ADODB.Recordset
Private Sub DataCombo1_Validate(Cancel As Boolean)
    On Error Resume Next
    
'    Uncomment this code as a workaround 
'---------------------------------------
'    If DataCombo1.Text = "" Then
'        rsDataSource.Cancel
'        rsDataSource.Move 0
'        Exit Sub
'
'    End If

    rsDataSource.Move 0
    MsgBox Err.Number & vbCrLf & Err.Description

End Sub
Private Sub Form_Load()
    
    Set rsRowsource = New ADODB.Recordset
    rsRowsource.Fields.Append "ID", adInteger
    rsRowsource.Fields.Append "Descr", adVarWChar, 255
    rsRowsource.Open
    
    For x = 1 To 5
        rsRowsource.AddNew Array("ID", "Descr"), Array(x, "Descr" & Str(x))
    Next x
    
    Set rsDataSource = New ADODB.Recordset
    rsDataSource.Fields.Append "ID", adInteger
    rsDataSource.Fields.Append "Foreign_ID", adInteger
    rsDataSource.Open
        
    DataCombo1.ListField = rsRowsource(1).Name
    DataCombo1.DataField = rsDataSource(1).Name
    DataCombo1.BoundColumn = rsDataSource(0).Name
    Set DataCombo1.RowSource = rsRowsource
    Set DataCombo1.DataSource = rsDataSource

    rsDataSource.AddNew
    
End Sub

Run the project. Click the DataCombo and move the mouse over the selections, however, do not select one.

Now click the other Textbox control so that the DataCombo loses focus. You will see the preceding error message display. Uncomment the commented lines of code to see the workaround.

REFERENCES

For more information on the DataCombo control, please see the Visual Basic 6.0 On-line help.

Additional query words: datacombo dropdown


Keywords          : kbCtrl kbVBp600 kbGrpVBDB kbGrpMDAC 
Version           : WINDOWS:6.0
Platform          : WINDOWS 
Issue type        : kbprb

Last Reviewed: May 27, 1999