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Error message “No exports were found that match the constraint contract name”
...}\AppData\Local
For those who have multiple versions of Visual Studio installed, e.g. 2012 and 2013, it might help to remove the ComponentModelCache for both versions before restarting Visual Studio, e.g. 11.0 and 12.0.
sha...
Why should I use a pointer rather than the object itself?
...
It's very unfortunate that you see dynamic allocation so often. That just shows how many bad C++ programmers there are.
In a sense, you have two questions bundled up into one. The first is when should we use dynamic allocation (using new)? The second is when should w...
Variable length (Dynamic) Arrays in Java
...ou want - which is inefficient and a pain for you.
Fortunately, there are all kinds of built-in classes that implement common data structures, and other useful tools too. You'll want to check the Java 6 API for a full list of them.
One caveat: ArrayList can only hold objects (e.g. Integers), not ...
Why isn't SQL ANSI-92 standard better adopted over ANSI-89?
...n years after it was approved, it's about time people start using it! And all brands of SQL database now support it, so there's no reason to continue to use the nonstandard (+) Oracle syntax or *= Microsoft/Sybase syntax.
As for why it's so hard to break the developer community of the SQL-89 habit...
ASP.NET: Session.SessionID changes between requests
... is the reason
When using cookie-based session state, ASP.NET does not allocate storage for session data until the Session object is used. As a result, a new session ID is generated for each page request until the session object is accessed. If your application requires a static session ID for t...
Why do enum permissions often have 0, 1, 2, 4 values?
... bit corresponds to some permission (or whatever the enumerated value logically corresponds to). If these were defined as 1, 2, 3, ... you would not be able to use bitwise operators in this fashion and get meaningful results. To delve deeper...
Permissions.Read == 1 == 00000001
Permissions.Writ...
When does invoking a member function on a null instance result in undefined behavior?
...) and (b) result in undefined behavior. It's always undefined behavior to call a member function through a null pointer. If the function is static, it's technically undefined as well, but there's some dispute.
The first thing to understand is why it's undefined behavior to dereference a null poin...
Test if string is a guid without throwing exceptions?
...if class identifier was obtained successfully
/// Negative if the call failed
/// </returns>
[DllImport("ole32.dll", CharSet = CharSet.Unicode, ExactSpelling = true, PreserveSig = true)]
public static extern int CLSIDFromString(string sz, out Guid clsid);
}
...
When to use virtual destructors?
...
Virtual destructors are useful when you might potentially delete an instance of a derived class through a pointer to base class:
class Base
{
// some virtual methods
};
class Derived : public Base
{
~Derived()
{
// Do some important cleanup
}
};
Her...
What's the difference between JavaScript and JScript?
...
Just different names for what is really ECMAScript. John Resig has a good explanation.
Here's the full version breakdown:
IE 6-7 support JScript 5 (which is equivalent to ECMAScript 3, JavaScript 1.5)
IE 8 supports JScript 6 (which is equivalent to ECMAScri...