DOCUMENT:Q172101 18-JUN-2001 [vbwin] TITLE :PRB: "Data Type Conversion Error" When Using a Data Control PRODUCT :Microsoft Visual Basic for Windows PROD/VER: OPER/SYS: KEYWORDS:kbGrpDSVBDB ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 - Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 - Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 - Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 - Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 ------------------------------------------------------------------------------- SYMPTOMS ======== Deleting the data from a text box bound to certain data types, such as an integer or date, causes Error 3421: "Data Type Conversion Error." NOTE: If you are using a dbGrid, it's Error Method will produce Error 16389. CAUSE ===== This is designed behavior of DAO. The data control is sending a NULL string to DAO and DAO attempts to coerce it to a number and fails. This is not a problem with the Data Control: The same behavior can be observed without the use of a Data Control, using only code. For example: Set db = OpenDatabase("nwind.mdb", False, False) Set rs = db.OpenRecordset("select shipvia from orders", dbOpenDynaset) rs.Edit rs(0) = "" RESOLUTION ========== Use the following code in the Data Controls Validate method to allow the edit to occur as expected by user: Private Sub Data1_Validate(Action As Integer, Save As Integer) If Text1.DataChanged Then Text1.DataChanged = False 'So this data is not saved Data1.UpdateRecord ' This saves the data that ' may have changed in the other controls ' Now clear the numeric field Data1.Recordset.Edit Data1.Recordset![Year Born] = Null Data1.Recordset.Update End If End Sub STATUS ====== This behavior is by design. MORE INFORMATION ================ Steps to Reproduce Behavior --------------------------- 1. Place a data control and a textbox on a form. 2. Bind the textbox to an integer column of a table. 3. Delete the data from the text box. 4. Move off the record. Note that you get the "data type conversion error in the error event of the data control. This happens with Jet 3.5, 3.0, or 2.5, but does not happen in 16-bit Visual Basic. Additional query words: kbVBp500 kbVBp600 kbVBp kbdse kbDSupport kbVBp400 kbVS97 ====================================================================== Keywords : kbGrpDSVBDB Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVB500 kbVB600 kbVB400Search kbVB400 Issue type : kbprb ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.