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La siguiente información incluye la documentación de último minuto y soluciones en Visual Basic 5.0 que no se agregaron al archivo ReadMe.Hlp instalado con Visual Basic 5.0. También se puede encontrar esta información en el archivo Readme.txt que se distribuye con Visual Basic 5.0 en Visual Basic 5.0 CD-ROM. Este archivo no se copia en el equipo como parte de la instalación.
Microsoft Visual Basic 5.0 ReadMe.Txt CONTENTS -------- 1. Unsigned Cabinet Files for Internet Download. 2. Use RichTextBox for Multi-line Capability on the SSTab Control. 3. Converting Replicated Databases. 4. Opening a Replica Database Created Through Visual Basic Code. 5. Removal of Implicit Transaction for SQL DML Statements. 6. GPF When Running Queries on Attached ODBC Data Sources. 7. Machines with More Than 1GB RAM. 8. Opening Jet 2.X File Format MDBs in Exclusive Mode. 9. Download Fails in Components with JET Dependency. 10. Issues with Entry of Non-Latin Characters. 11. Rich Error Handling Suggested in Initialization Code for ActiveX Documents. 12. App.Path Property and CurDir Function May Return UNC Paths, Depending on How the Program/Project is Run. 13. Fix to Excel Sample Code in Programmer's Guide. 14. Print Method Is Not Listed in the Object Browser or with Objects it Applies To. 15. Internet Transfer Control: Error Constants Updates. 16. Component Download Fails for DCOM Projects. 17. Controls that Support DataBindings Property at Design Time. 18. ActiveX Document Internet Download Issues. 19. Download Problems with Multiple VB5-Authored Controls on a Single HTML Page. 20. ActiveX Designers May Not be Used in Unattended Servers. 21. GPFs on Startup of Visual Basic 5.0. 22. Visual Basic 4.0 Event Procedures May Cause Errors in Visual Basic 5.0. DETAILS ------- 1. Unsigned Cabinet Files for Internet Download. In the \Tools\cabinets folder on the Visual Basic 5.0 compact disc, you will find run-time and control .cab files used for Internet component download. These .cab files are not digitally signed so they should only be used for testing Visual Basic 5.0-authored control download. Additionally, these .cab files are not suitable for referencing directly from an HTML page. For example, you can not point to the Comdlg32.cab supplied on the Visual Basic 5.0 compact disc directly from an HTML page using the CODEBASE tag. The latest digitally-signed .cab files are available on the Microsoft Web site. To download these .cab files, go to: http://www.microsoft.com/vbasic/icompdown/ for more information. For more information on the Setup Wizard, digital signing, safety, and licensing, read the file Compdown.doc in the \Tools\docs directory on the Visual Basic 5.0 compact disc. 2. Use RichTextBox for Multi-line Capability on the SSTab Control. Use the RichTextBox control to provide multi-line capability on the SSTab control. The following steps on NT 4.0 may result in an application error and cause Visual Basic to close: A. Open an ActiveX control project. B. Put an SSTab control on the UserControl object. C. Put a TextBox control on the SSTab control. D. Set the TextBox control's Multi-Line property to TRUE. E. Close the UserControl designer. When you're prompted to save changes, click No. F. Open the File menu, choose the Add Project command, and double- click the Standard EXE icon on the New Project dialog. G. Put your ActiveX control on the form. H. Press the F5 key to run the project. I. Click the Stop button on the Visual Basic 5.0 toolbar. The following points are key: - The SSTab control is on the UserControl object. - The TextBox is on the SSTab control. - The TextBox control's Multi-Line property is set to TRUE. 3. Converting Replicated Databases. Visual Basic 5.0 cannot open a replica created with Visual Basic 4.0. You must convert the Design Master to Visual Basic 5.0 and then synchronize with the associated replicas. 4. Opening a Replica Database Created Through Visual Basic Code. If you make a database replicable using Data Access Objects (DAO) through Visual Basic 5.0 and then move the database to a different directory without first opening it, you will receive an error when you try to open the database. If you create a replica using DAO and then try to open the replica before opening the Design Master, you will also get an error. To solve this problem, when you replicate a database using DAO, open the Design Master in Visual Basic 5 and synchronize all replicas before moving the Design Master or opening a replica. 5. Removal of Implicit Transaction for SQL DML Statements. Even with all the work in Jet 3.0 to eliminate transactions in order to obtain better performance, SQL DML statements were still placed in an implicit transaction. This negated some of the performance work and typically resulted in DAO looping code to substantially outperform SQL DML statements. Jet 3.5 has removed that restriction and SQL DML statements are no longer placed in an implicit transaction. This results in a substantial performance benefit when running SQL DML statements that affects many rows of data. While this change provides a substantial performance increase, it also introduces a change to the behavior of SQL DML statements. Previously, the result of an SQL DML statement would roll back if any part of the SQL DML statement could not be completed. This was due to the fact that it was placed in an implicit transaction. It is now possible to have some of the rows affected by a SQL DML statement to be modified while others are not. If this behavior is not desired then the user will need to add explicit transactions around the SQL DML statement and sacrifice the performance gains. 6. GPF When Running Queries on Attached ODBC Data Sources. A GPF occurs if any relationship is defined on an MDB and a subsequent query through attached tables to ODBC data sources is used to do a join. This only occurs with Access 97 and this release of Jet 3.5 corrects that problem. 7. Machines with More Than 1GB RAM. All versions of Jet 3.0 and previous versions of Jet 3.5 would not start if a machine had more than 1GB RAM. This is fixed in this release of Jet 3.5. 8. Opening Jet 2.X File Format MDBs in Exclusive Mode. Certain scenarios when using Access 97 and Jet 3.5 would prevent users from opening a Jet 2.X file format database in shared mode. This issue is addressed in the release of Jet 3.5. 9. Download Fails in Components with Jet Dependency. Code download might fail if your Visual Basic component has a dependency on MSJet35 and is downloading to a machine with Office 97 installed. As with all code download failures, there is no indication to the user as to why the failure occurred. Below are the steps a developer should take to work around this problem: A. Start Setup Wizard, and select Internet Download Setup to create a .cab for component download. B. Open the Support folder of the location where the control's .cab was created. The default location is Win95\Temp\Swsetup or WinNT\Temp\Swsetup. C. Open the control's .inf file. D. Make following changes to the .inf file: 1. Remove this line from the [Add.Code] section: VBAJET32.DLL=VBAJET32.DLL 2. Remove the entire Section [VBAJET32.DLL]. E. Save the .inf file. F. Run Makecab.exe. Makecab.exe is located in \Setupkit\Kitfil32 below the folder where Visual Basic is installed. The /f parameter needs to be used. To do this, follow the steps below: 1. Copy Makecab.exe to the Swsetup folder. 2. Open the Win95 Start menu, select Run, and enter the following string: makecab /f yourcontrolname.ddf. 10. Issues with Entry of Non-Latin Characters. Many Win32 API functions are coded to use the System LCID setting. If the User and System LCID settings don't match, you may see issues in Visual Basic such as dialogs and controls displaying illegible text on entry of characters from non-Latin alphabets. It is possible to fix the problem in NT by checking the "Set as system default locale" check box in the Regional Settings and then rebooting the system. Windows 95, on the other hand, sets the System LCID at install time. It is advisable to install the localized version of Windows 95 with the same language as the User LCID. If using the Pan- European version of Windows 95, it is necessary to perform a Custom Installation and select the correct locale during the setup. However, while Visual Basic controls may behave properly once System and User are synchronized, entry of non-Latin characters will still result in illegible text displaying in Visual Basic's design environment (IDE) dialogs. Functionality is maintained, however. 11. Rich Error Handling Suggested in Initialization Code for ActiveX Documents. When untrapped errors occur in the Initialize event of an ActiveX document, Internet Explorer may display an error message indicating that it is unable to load the .vbd file. It is strongly suggested that you put rich error handling in place in any initialization code for UserDocument objects. 12. App.Path Property and CurDir Function May Return UNC Paths, Depending on How the Program/Project is Run. In Visual Basic 5.0, App.Path returns a UNC path (\\server\share...) rather than a drive path (E:\folder\folder...) in the following circumstances: - When a project is run after being loaded from a network share, even if the network share is mapped to a drive letter. - When a compiled Exe is run from a network share, but only if the Exe is run using a UNC path. This is a change from Visual Basic 4.0 and may cause problems for some existing code. The problems for compiled programs are different from the problems that occur when running a project in the development environment: COMPILED EXE: Some projects use the following two lines of code in Sub Main to change the current directory (as returned by the CurDir function) to match the startup directory (as returned by App.Path): ChDrive App.Path ChDir App.Path ChDrive cannot handle UNC paths and will raise an error when App.Path returns a UNC path. You can handle this error by placing On Error Resume Next before the ChDrive statement or by testing the first two characters of App.Path to see if they are backslashes: On Error Resume Next ChDrive App.Path ChDir App.Path This modification handles all cases in which the program is started from Windows using a UNC path (for example, in the Run dialog accessed from the Start menu), because Windows sets the current directory to a UNC path. ChDir handles changes between UNC paths correctly. (The failure of ChDrive can be ignored because there is no drive letter for a UNC path.) However, the code above will not work if a user runs the program by typing a UNC path at the command line of a DOS window. This is because a DOS window always has a drive path for the current directory, so CurDir is set to a drive path. ChDir does not raise an error, but it fails to change the directory from a drive path to a UNC path. The only workaround for this is to locate a local drive that's mapped to the share specified in the UNC path or to use network commands to create such a mapping. IN THE DEVELOPMENT ENVIRONMENT: If the project was loaded from a network share, either a UNC path or a mapped drive path, then App.Path will return a UNC path when the project is run. ChDrive will fail and raise an error. ChDir will not raise an error but the directory will not be changed. The only workaround is to set the drive and directory manually, as in the following example: Const PROJECTSHARE = "E:\VBPROJ\MYPROJECT" #Const Debug = True #If Debug Then ChDrive PROJECTSHARE ChDir PROJECTSHARE #Else On Error Resume Next ChDrive App.Path ChDir App.Path #End If If more than one developer might open the project on the network share, a DOS environment variable can be used to allow each developer to have his or her own mapping for the share: #Const Debug = True #If Debug Then ChDrive Environ$("MYPROJECTDIR") ChDir Environ$("MYPROJECTDIR") #Else On Error Resume Next ChDrive App.Path ChDir App.Path #End If The value of MYPROJECTDIR specifies the mapped drive letter and the path. For example: SET MYPROJECTDIR=M:\VBProj\MyProject. Note that the Help topics for the Path property, ChDir statement, ChDrive statement, and CurDir function do not mention this changed behavior. 13. Fix to Excel Sample Code in Programmer's Guide. In Chapter 10 of the Programmer's Guide "Programming with Components," the section "Working with ActiveX Components" contains sample code adding values to Excel. Add the line: xlBook.Close immediately above the statement xlApp.Quit. This ensures that all Sheet objects are released. 14. Print Method Is Not Listed in the Object Browser or with Objects it Applies To. The Print method applies to the Form, Printer, PictureBox, UserControl, UserDocument, PropertyPage, and Debug objects. In Help, the Print method should appear in the Methods lists of all of these objects although, in fact, it only appears for the Debug object. In addition, these objects should all appear in the Applies To list in the Print Method topic although, in fact, only the Debug object appears there. For technical reasons, the Print method does not appear in the Object Browser, even though it is a valid method of the objects listed above. 15. Internet Transfer Control: Error Constants Updates. The Help topic "Trappable Errors for the Internet Transfer Control," contains the following duplicates and errors: A. There are two entries for icnetTimeout (35768). The second can be ignored. B. The value for the constant icIncorrectPassword should be 35780. C. The value for the constant icHttpToHttpsOnRedir should be 35805. D. The value for the constant icHttpToHttpOnRedir should be 35806. E. The description of icFtpDropped (35877) should be "FTP - Connection dropped." 16. Component Download Fails for DCOM Projects. The .cab installation will work if the RemoteReg .cab is located in the same folder as Msracli.cab. If Msracli.cab is located in another location, component download will fail. The workaround is to modify the .inf file so that Msracli.cab is located in the local folder. This means you need access to Msracli.cab and must know how to build a .cab without Setup Wizard. 17. Controls that Support DataBindings Property at Design Time. The online Visual Basic Help documents the following controls as having a DataBindings property that can be accessed at design time. Some of them, however, do not, in fact, support accessing their DataBindings property during design time even though they have a DataBindings property. The following list clarifies which controls support the DataBinding property at design time: DBList - Yes DBCombo - Yes DBGrid - No Toolbar - No TabStrip - No MaskedEdit - Yes MSChart - No MSFlexGrid - No MCI - No RichTextBox - Yes Slider - No SSTab - No 18. ActiveX Document Internet Download Issues. The sample HTML page created by the Setup Wizard for ActiveX Document- based projects will download and register the Visual Basic 5.0-created EXE or DLL and then jump to the .vbd file. The jump from the HTML page to the .vbd file will prevent any merged menus from displaying. Additionally, the DataChanged method will not operate correctly. The workaround is to replace the Setup Wizard-generated HTML Window_Onload event code with the following (where Userdocument1.vbd refers to your vbd filename): Sub Window_OnLoad Window.Navigate "userdocument1.vbd" End Sub NOTE: You can bypass the HTML page altogether and navigate directly to the .vbd file after the Visual Basic 5.0-created .exe or .dll has been successfully downloaded to the client. For the latest information on the Setup Wizard and ActiveX Document Internet download, go to http://www.microsoft.com/vbasic/icompdown/ and read the file Compdown.doc in the \Tools\docs directory on the Visual Basic 5.0 compact disc. 19. Download Problems with Multiple VB5-Authored Controls on a Single HTML Page. If a single HTML page will contain multiple Visual Basic-authored ActiveX controls, put all of the controls into a single Visual Basic project and run the Setup Wizard on that project. The Setup Wizard will create a single CAB file for all the controls. The containment of all controls within a single CAB file minimizes download time and removes the possibility of files being downloaded more than once. 20. ActiveX Designers May Not Be Used in Unattended Servers. Visual Basic 5.0 does not support the use of ActiveX designers in multi- threaded (unattended) components. The UI prevents this in most cases, but there is a small loophole present that allows you to build a Visual Basic component containing ActiveX designers and mark the server as "unattended-execution," which in turn registers that component as "Apartment-Threaded." Doing this is unsupported and does not produce favorable results. For example, marking a project that contains a UserConnection designer as "unattended execution" and using it in a multi-threaded environment, such as the Microsoft Transaction Server, results in "Out of Memory" errors or more severe problems. The workaround is to always compile projects containing ActiveX designers as single-threaded. In other words, in these cases do not check "Unattended Execution." 21. GPFs on Startup of Visual Basic 5.0. If you get a GPF during startup of Visual Basic 5.0, it is probably caused by an incompatible add-in. You should edit the Vbaddin.ini and set all entries to zero. Once the entries are set to zero, Visual Basic 5.0 will not load any add-ins on start-up. You can then use the Add-In Manager to add back add-ins that are working properly. If you get a GPF on start-up of the Visual Basic Learning Edition, it may be caused by add-ins installed by the Visual Basic Control Creation Edition Beta. The workaround is the same as above. Also, you should install the released version of the Control Creation Edition. 22. Visual Basic 4.0 Event Procedures May Cause Errors in Visual Basic 5.0. Visual Basic 4.0 did not recognize some typelib-defined data types, such as OLE_HANDLE. When these types were used in event arguments, Visual Basic 4.0 would replace them with the corresponding native type (in this case, Long). Thus, Visual Basic 4.0 would produce the following event procedure for an event with an argument of type OLE_HANDLE: Private Sub SomeControl1_SomeEvent(ByVal oh As Long) End Sub If this same event procedure prototype is created in Visual Basic 5.0, the correct data type will be used: Private Sub SomeControl1_SomeEvent(ByVal oh As stdole.OLE_HANDLE) End Sub If code generated in Visual Basic 4.0 is imported into Visual Basic 5.0, the event types will not match and the code will not compile. The solution is to cut the code from the existing event procedure, delete the event procedure prototype and recreate it in Visual Basic 5.0, and then paste the code back into the event procedure.
Id. de artículo: 167167 - Última revisión: martes, 18 de noviembre de 2003 - Versión: 2.0
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