How to make use of HTTP headers to control the caching of Web pages in ASP and IIS, known to work with Internet Explorer.
How to use #ifdef and #ifndef to check if an identifier has been defined
#ifdef, #ifndef and #endif are preprocessor directives which allow us to check wether or not a value has already been defined using the #define directive. This can be useful when you’re including files that may already have the same value defined using #define. Here’s an example that defines the value Whidbey only if it wasn’t defined before: #ifndef Whidbey#define Whidbey#endif Similarly, what’s between #ifdef and #endif is compiled […]
AutoPostBack – How to submit (PostBack) page when a DropDownList item is selected
Thanks to the AutoPostBack attribute, you can easily submit the form when the user selects an item from a DropDownList. All you need to do is set the AutoPostBack attribute to true inside the DropDownList tag, as seen in the following example:
How to convert C++ variables to other data types using casting
There are several ways to convert C++ variables.Here is one method of converting an integer variable to a bool (boolean) variable: int MyInteger = 0;bool MyBool = (bool)MyInteger; And here is another way: int MyInteger = 0;bool MyBool = static_cast<bool>(MyInteger); In both cases, after the casting has been made, MyBool will contain the value false (since MyInteger was 0). If MyInteger was 1 or any other number […]
How to convert a variable from double to float
A variable of type double can easily be converted to float or any other similar data type, in C#:
Using AI to Detect Anti-Patterns in Code
In the intricate ballet of software development, anti-patterns represent the missteps — the common yet ineffective solutions to recurring design and programming problems. Unlike patterns, which are best practices that developers follow to create maintainable, scalable, and efficient software, anti-patterns are pitfalls that may seem to provide a quick fix but ultimately lead to additional […]
How to detect if the visitor of a website is running Windows Vista
Different languages have different ways of getting information about the visitors. However, most languages can get the User Agent, which provides us, the webmasters, with information about the visitor’s browser, plugins and operating system. For example if the user agent of a visitor is: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322) Windows […]
Object cannot be cast from DBNull to other types
This is a common error that you get when trying to display a field with no value (null), from a table. If for example you have a field where you store the age of the employee, but you don’t know the age of all employees, and thus those fields are set to NULL. Trying to retrieve […]
How to detect if the visitor of a website is using Internet Explorer 7 Beta 1
Looking at the user agent we get information about the visitors, such as the operating systems they are running, browsers they are using, or what version of .NET Framework they have installed. The user agent is retrieved differently depending on the programming language you are using for your website. Since Internet Explorer 6.0 is the dominant browser, […]
A page can have only one server-side Form tag
In ASP.NET 1.1, only one server-side form tag is allowed on a page. This error occurs if you have two or more server-side form tags on your page.A server-side form tag is the tag which has a runat=”server” attribute. If this attribute is missing, then it’s a typical HTML form tag. The conclusion is that you are […]