To get the memory usage information you can use the System.Diagnostics.Process class. As I wantet to check the memory usage regularly I kept the reference to the Process object in my class. But the value never changed anymore… Then I tried to get the Process object every time i needed the current memory size – and it worked.

So I read the documentation a little more carefully and got to this part:

The process component obtains information about a group of properties all at once. After the Process component has obtained information about one member of any group, it will cache the values for the other properties in that group and not obtain new information about the other members of the group until you call the Refresh method. Therefore, a property value is not guaranteed to be any newer than the last call to the Refresh method. The group breakdowns are operating-system dependent.

So I changed my code again to not get the Process every time I wanted the current memory size but call the Refresh method.

And what did we learn from this episode?

Michael A. Jackson (“The First Rule of Program Optimization: Don’t do it (…)“) and Donald Knuth (“(…) premature optimization is the root of all evil (…)“) are right. Don’t do optimization, especially not if you don’t really know what you are doing…

Coming from the C++/C#/Java world, the ‘this’ keyword is well known for accessing the instance of the class itself. For accessing members, it is not mandantory but often favored for clearness.

With this background, a first try could look like this (complete html page in the package, file this1.html):

And the output is:

OK, let’s try again!
We call the name property explicit (this2.html):

And the output is, as expected:

So, it’s a piece of cake, we have only to put the this keyword for all members, and we’re done…

Wait, not so fast, youngster!

Let’s try it with a function reference like in the next example (this3.html):

And the output is:

The name is lost again!

This problem occurs because JavaScript doesn’t support implicit binding in a way C++ and others do.

With calling the function through the function reference, the this inside the hello function points not to marc but to the window. To verify this thesis, we just add a name to the window:

And the output is:

But how can we solve this problem? The two easiest solutions are apply and call:

And the output is:

With apply and call, you do an explicit binding. The object you pass as the first argument (in our example marc) does not need to have the function itself, but should of course have the members that are used inside the function.
The difference of apply and call is only in the signature of the function. With apply, the parameter have to be passed inside an array. With call, the parameters are lined up after the explicit binding object.

This should give you some ideas to identify problems coming from the binding and some solutions to solve them.

For further reading i suggest the following articles:

• Getting Out of Binding Situations in JavaScript
• What is this? – OOP in Javascript zähmen (in german)

For an Web Application I needed not only to check the user rights but also to limit the the allowed computers. For this I limited the access with a client certificate that has to be installed on the accessing computer.
At the beginning I used a free client certificate from Thawte, as the server certificate was also from them. This certificate was only valid for one year. So I had to renew this certificate every year and all allowed computers had to be updated.
But as Thawte ended their support for the free certificate I needed an other solution. I chose to use a self signed certificate as the client certificate but keep the server certificate from Thawte as on the server were also running other Web Applications that needed https.
So I created the Certification Authority (CA) certificate and a client certificate signed with this CA certificate with openssl. Testing with this certificates worked as it should. But for Testing purposes I used the default values for the validity length. So I created a new CA and a new client certificate with a longer validity period. After removing the testing certificates and installing the new created certificates I thought it will work as before, but the client certificate was not selectable in the client certificate selection dialog of internet explorer.
I tried several things like restarting IE, clearing the SSL cache and cursing. But nothing helped.
Analyzing the communication between client and server with openssl brought the solution: The Internet Information Server (IIS) was still using the old, already removed CA certificate, probably from his cache, but not the new one, maybe because the were named similar. After restarting the IIS on the server the new client certificate was selectable in the client certificate selection dialog of internet explorer.
Conclusion: After removing a (CA) Certificate from the IIS restart it to clear the cache!

Hold both soft keys (the two keys that represent the options on the screen), push the reset button with the stylus and keep the two keys until the screen shows the options to continue the operation.

Warning: All data (contacts, sms, installed software, pictures etc) wil be ereased!

Imagine you have a database table with a cloumn id of the data type integer that has set the IDENTITY. You use a stored procedure to insert a new entry into this table. Inside this stored procedure you use the SCOPE_IDENTITY() function to get the identifier created for this row. With RETURN SCOPE_IDENTITY() you give the identity to the caller.

You call this stored procedure from a SqlComand with ExecuteReader() that returns you an SqlDataReader object.

From this SqlDataReader you read now the identifier with GetInt32().

Wrong !

This will give you an InvalidCastException. SCOPE_IDENTITY()’s return type is numeric, although your identifier column is an integer. SqlDataReader’s GetXY functions do not convert the data and throw the exception when the data is not already of the right type.

The first solution

You can read the value with GetDecimal() and cast the value to an int:

The second solution

You cast the identifier inside the stored procedure und return it already as an integer:

Whatever solution you choose, take care that you use always the same inside your application.

I had to reformat a date in Javascript. There were all this little nice functions of a date object like

and also

. Every of these functions returned the value as it would also be shown, but not getMonth(). getMonth() returns a value from 0 to 11, so 0 is January, 1 is February and so on untill 11, that is December.

I see a possible reason for this: With values from 0 to 11 you can use the value directly as the index for an array with the month names inside, like

The command ISNULL uses the first parameter, if it is not null, or the second parameter if the first is null. When you pass a value, this value is used, but when you pass null the current value of this column is used, so it overwrites it with the same value.