You can apply operator dynamic_cast only to polymorphic objects (a polymorphic object is one that has at least one virtual member function). This is a requirement of the C++ standard.

Question: I have some orphaned Exchange mailboxes that are displayed under Private Information Store/Mailbox Resources. How do I remove them if the object is not defined in the DS? Answer:

The standard DAO Data control is designed to work with the Jet 3.5 Engine, whereas Access 2000 database can be accessed only by the more recent Jet 3.6 engine. For

Date variables store values in floating point format, much like Double variables, with the integer part for dates and the fractional part for the time portion. Being floating point values,

If your ASP pages display strings stored in database fields, you should always process the strings with the Server.HTMLEncode method, otherwise the string won’t be displayed correctly in the user’s

After you install Visual Basic and log on to the machine as a different user (with or without administrator privileges), you cannot see any Add-Ins in the Add-In dialog in

Have you ever read a message like “Dependency file for COMCTL32.OCX is out of date” during the package creation process? The cause of this problem is simple: you have installed

When you assign a reference to a form (or one of its controls) to an object variable which is stored outside the form module, you must set the variable to

If you instantiate an ActiveX component from an ASP script under IIS 4 and previous versions, using the Server.CreateObject command, you might believe that the object is deallocated as soon

A SELECT query returns all the rows for which the WHERE clause returns True. However, many developer – especially those accustomed to other programming languages, such as VB – get

In SQL Server 6.5 and previous versions, the GROUP BY clause in a SELECT statement was carried out by temporarily sorting the resultset before grouping similar rows, therefore the end

One of the resource dispensers that come with MTS is Shared Property Manager (SPM). SPM provides a mechanism by which you can share global memory among all the objects that

Question: According to the stats of my Web site, there are still quite a few users who use old browsers like Netscape 3.0 and Explorer 3.0. If I start using

Question: I am using a disconnected recordset (adOpenStatic, adUseClient) which is obtained by executing a stored procedure using command an object. I tried to delete some fields from the recodset

Question: Can Javascript code be used in XHTML Web pages? Answer: Sure. The only real difference between XHTML and HTML is the consideration for ampersands and less than symbols. Thus,

Question: When I try to send some information to an access database through ASP, I get the following error: [Microsoft][ODBC Microsoft Access 97 Driver] Field ‘tablename.class’ can’t be a zero-length

Question: What is the difference between SOX schemas and XDR schemas? Answer: SOX schemas are more object-oriented (the name in fact means Schemas for Object-Oriented XML), allowing you to assign

Question: Is there any way to do a incremental save using XMLDOMDocument (MSXML parser) and also loading part of the Document tree? Answer: A SaveInto or a LoadFrom command? As

Question: When setting up a recordset, is it possible to get a record when the field contains more than the word that I’m looking for and where the words are

XML has a special set of characters that cannot be used in normal XML strings. These characters are: & – & < - < > – > ” – "

If a user runs a page on our site and has not yet logged in, we can redirect him to the correct login page with the following script: Related Posts

Of course no one ever sees an error on your Web site?but just in case, you can turn off explicit ASP error messages on your live site for better security

Question: How can I pass a member function of a class as a pointer in C (pointer type expected: void *)? Answer: You can’t pass a pointer to a C++

Question: Using Visual C++ 6.0, I recently attempted to create a structure to implement a data message that my application had to process. The following code segment produced unexpected results

Question: What is the “clear screen” function in C++, and which library is it in? Answer: Standard C and C++ don’t define a function that clears the screen. DOS and

Question: On the Indexes tab of Visual FoxPro Table Designer dialog, you can define a Primary Index. How do I do the same thing through code in a FoxPro program?

Question: What are the pros and cons of creating extended stored procedures? Answer: The pros are that you can implement additional functionality and access data from DLLs from within SQL

Question: From a database-efficiency standpoint, which is better for SQL when inserting new rows into a table: issuing ad hoc SQL statements in the form of “Insert Into…” or using

Question: I have a memo field in a table, which has been scattered to memvar. I need to append a standard statement to the field once the user has completed

Question: How do I print out all of the tables, the fields the tables contain, and the datatype of the fields in my accounting database (for report creation)? I am