Happy holidays from telerik :)

Posted by Stephen Forte, here are some greetings from telerik offices:

http://www.stephenforte.net/PermaLink,guid,d29db13e-a239-49e6-b620-b72e8980c662.aspx?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+StephenFortesBlog+(Stephen+Forte`s+Blog)&utm_content=Google+Reader

:).

Introduction to programming with C#

As Vesko Kolev stated in his blog - a new bulgarian book about C# programming is in progress.
I decided to take part because it seems very interesting. I haven't much experience in publishing so it will be very beneficial for me to work on this.
Actually I was author in a software magazine few years ago (as far as I remember I was about 17 years old so it must have been about 6 years ago). It should help me as I took the first chapter - introduction to programming where I will show the readers how to install Visual Studio 2010, how to start their first project and how to write their first program, some diagrams of the .NET framework 4.0 will also be included in this chapter.

We decided not to include any advanced features in this book, just core programming language, no extensions, no lambda expressions, no var, no automatic properties, no nothing.
This is because this book targets potential software developers and not software developers. It should show the developer how to code, how to think etc. We decided that if a man / lady without any software experience may think that auto property won't take memory after it doesn't involve variables (at least visualy :).
That is why we do only core things.

Wish us luck. We would really love to expand bulgarian software development community with few more people :). After all if even one guy / gal of all the people that will potentiall read the book becomes an expert - our mission would be completed (we are dreaming for more impact ofcourse :).

As Svetlin Nakov and Vesko Kolev said - telerik is sponsor for this book so it should be published easilly than their prеvious book - "Introduction to programming with Java" and would probably joy some more marketing efforts.

That was it about the book.
Now about my motivation to join the project no matter my personal engagements and all the work I have at telerik and at the university.
The first reason is that I am a self - taught (almost) developer.
I never had degree that will help me find my work, join some society of developers that will help me when I hit a difficult problem.
There wasn't even internet in my hometown. A friend of mine gave me a book on programming with Delphi (that Sams 21 days brick :).
The Delphi help also helped me and I also downloaded html files to read later when I was at school.

Then I applied for a job in the city where I was studying (Veliko Tyrnovo).
It was all my collegues that helped me improve my skills.
I don't feel as a worldwide recognised expert or something but getting to the intermediate level from nowhere is achievement to me.
So reason #1 to join this book is to give something back.

Another reason is that I would like to see how a book is written, are there different proccesses than in the software development. It has something to do with the blog posts I guess :)
So reason #2 is to steal some knowledge :)

And some kind of nostalgy would be the last reason to join :).As I said, I was an editor in a software magazine, it was very nice thing to do. The article, then the readers asking for some more information. I miss this a bit :)
Reason #3 - to feel the old days when I was an editor :)

The specified service has been marked for deletion error message when removing a service

If you receive this message while trying to delete a windows service - check if the Services.msc application is open.

You will need to restart in order to delete the service, but you will know to first close the Services.msc application the next time PRIOR uninstalling the service (using installutil /u service_exe_name).

Hope this helps someone outthere...

Edit : I found another scenario when this can happen and it seems to be more .NET specific and common to software developers - if your service creates some worker threads, Windows will attempt to kill the main thread, the main thread will attempt to kill the main thread but the worker threads if not marked as BackgroundThreads via the IsBackgroundThread property will remain. The GC will wait for them to reach a safe point so they can be terminated and the service will most probably be only marked for deletion, requiring you to restart windows.

Please note - if you are using the ThreadPool class you will probably not hit this problem as the ThreadPool internal threads are automatically marked as background threads.

Edit 2: Another case when you will receive The specified service has been marked for deletion error message is when you try to uninstall service which wasn't stopped first or it was marked as unstopable.
This is done if you have this.CanStop = false in your service code.
Windows knows this service shouldn't be stopped and it will only mark it for deletion but will not delete it right away.
Be careful with CanStop property.

Limiting your Internet connection speed with Fiddler.

In some cases you may need to limit your connection for testing purposes.
This is / should be extremely easy using Fiddler.
Here is a simple walkthrough on how to do this:

1. Go to Fiddler site and download Fiddler latest version (http://www.fiddler2.com/fiddler2/)
2. Install it and start it.
3. Click on Rules -> Customize Rules:

4. An instance of notepad should open. Find the line that says something like "oSession["request-trickle-delay"]":

This setting tells Fiddler how much milliseconds should halt the request. (not quite sure how a request halt will help you though)
5. Find the line that says "oSession["response-trickle-delay"]" and change it:


Save the file.
You should have a connection limitation.
Now, when you want your connections slowed down, you will need to check the following option:

6. Rules -> Performance -> Simulate Modem Speeds (should be checked):


Please do not forget to switch off fiddler when you don't need it as you may find yourself wondering why is your connection significantly slower than usual ;).
Hope it helps someone out there.

Telerik after few days of work

I wasn't blogging for a while but I was concentrated at my new work ;).

Actually I had forgotten that I have blog but few collegues were joking with me that I suddenly put my blog posts (especially those focussed on radControls) on hold. They also asked me if I am going to stop writing about telerik :).
So I decided to write about telerik ;). This time from other prospect.
I was thinking a lot about this post.
If I only praise the company the readers may think I have some interest to do so.
So here is the truth.

I will first start with the interview.
It was held in telerik HQ here in Sofia (my position is also here), the people who was responsible for the interview did their job in a very professional way. The interview was very easy to handle and more like a chat with friends. No stress at all.

The technical questions were handcrafted in a way so the interviewers can get an idea of my technical skills without bothering me with a questions like : "Do you know what is the method in the System.x.y.z.Class which should be used to do access NASA space shuttle chip N1A2322AH". I mean I can remember some of them but I can't know each method in the .NET framework, all the commands in the TFS, all the things in jQuery etc.
No such questions. But real technical questions instead. I will not disclose more on that.

Some processes which I will also skip took place in a matter of week.

The first day
It was a day to get familiar with the company, the collegues etc. telerik HR manager introduced me to all the teams, I met all the people, got some other technical orientation meetings and was ready to go.

The task
I had a challenging task (challenging to me at least, it may be easy to do for other people). Anyway it kept my interest all the time until it was finished. Offcourse I will not disclose more details on this. Just to let you know that I was happy with it.

The meetings
Everything is discussed, each collegue is helpful, there are meeting rooms which are available for longer meetings and you can also go to your collegue desk for shorter discussions.

The people
As I said the people are quite friendly.
Lots of smart guys there. You can learn and teach. Also I have a lot of friends who were collegues of mine from previous companies. They really helped a lot to integrate.

So will I continue to write about radControls
Probably not. At least not that often. When I was at my previous work I had found some problems with the controls because I needed to implement some uncommon scenarios. As I stated in my posts - some of them was because of lack of knowledge in rad products. Now if I have problem I can internally ask someone from the team to help me out or if I find an issue we can discuss if we can address it or find a workaround. That wasn't quite possible before. So I may write a post on how the issue was resolved instead just pointing it out.

Disclaimer :)
The above is my personal opinion based on about a week work.
May or may not change in time. Hope it will not :).

First day at Telerik

Just to update you that tomorrow is my first day at Telerik.
Wish me luck!

A nice sentence I read recently

This one is from the asp.net forums:
"Where there is a will, there is a way. And where there is a team there is more then one way."

Determine if your site is running under IIS or Casini

For the people who don't know - Casini is the built in Visual Studio server which is by default running when you debug ASP.NET project.
You can use the following to check if the site is running under IIS:

bool isUnderIIS = this.Request.ServerVariables["SERVER_SOFTWARE"].IndexOf("IIS") > -1;

Not the most clever thing I've ever done but seems to be the only way at the moment.
If you know a better way - let us know...

To clarify - IIS will return something like : "Microsoft-IIS/5.1", while Casini will let you bump your head with string.Empty.
Anyway, this covers my scenarios 100% so I can use it.

A nice DOM property I bet most of you have missed ...

In my previous post on this topic I mentioned the properties you can use to detect changes in HTML input controls:
http://donchevp.blogspot.com/2009/08/nice-dom-property-i-bet-most-of-you.html

Now I want to inform you that I have found an article which has all the controls included with the property you can use to track for changes:

http://www.codestore.net/store.nsf/unid/DOMM-4UTKE6

The first thing I noticed is that it is kind of inconvenient for the SELECT DOM object for example.
You should iterate through all the items and check their selected property with their defaultSelected property ...

A nice DOM property I bet most of you have missed ...

Have you ever heard about the defaultValue and the defaultChecked properties?
They seems to be a standard DOM properties so the major browsers seem to support them.
What they do?
The defaultValue property is about textboxes (input type="text") and it will contain the value which the textbox has at the time it was rendered on the page.
The defaultChecked property is almost the same, it is about a checkbox and it tells you whether the checkbox was rendered checked or not.

So doing something like:

function hasTextBoxChanged(textBox) {
return textBox.defaultValue == textBox.value;
}

would tell you whether the textbox passed as an argument has changed its value since it was rendered on the page.

Same function for checkbox would be something like:

function hasCheckBoxChanged(checkbox) {
return checkbox.defaultChecked == checkbox.checked;
}

I find those properties very helpful. If you play a bit with jQuery you can find a real life application of them.
I am however wondering if there are such properties for dropdowns and some other controls.
If I find - I'll definatelly post again.

Hope it helps someone outthere ...

P.S. if the control is a part of update panel and it was udpated in the code behind it will not be counted as a change as the defaultValue / defaultChecked properties will be set again (those properties are taken to be the value of the control when it was rendered).

Join the W3C feature suggestions group in Facebook!

You want to see a feature as a part of the W3C standard?
Join the W3C feature suggestions group in facebook:

http://www.facebook.com/srch.php#/group.php?gid=111306074563

You may find the feature already included or find a workaround ...

Work in a cooperation with your compiler. Always tell the truth about your datatypes!

When you have a cast you should avoid asking the compiler to figure out what kind of data should be returned. This is more about objects and the string data type.
For example I've seen (and to be honest I myself did the following mistake when getting data from DataSet. Don't laugh in .NET 1.1 and 2.0 there was no Linq :)

foreach (DataRow row in dsReportSource.Tables[0].Rows)
{
string strName = row["name"].ToString();
}

The compiler will let you think that it knows how to do the fastest transformation from object (in the dataset all the columns in a row are objects) to the destination type (in our case - string). But it will only let you think so. What will actually happen is that the compiler will slow down the data acquisition due to some internal checks and conversions ...

Instead do the following (as you are more than sure that this column is string):

foreach (DataRow row in dsReportSource.Tables[0].Rows)
{
string strName = (string)row["name"];
}

This way you tell the compiler - "Look, don't even bother to try to infer the type for me. I am telling you this is a string, so please just treat it as string). And it makes sense - after you have a column of type NVARCHAR in the database it will always come to you as a string (masked as object :).

Now there are even worse cases like:

foreach (DataRow row in dsReportSource.Tables[0].Rows)
{
int iId = int.Parse(row["id"].ToString());
}

As you can see you are parsing the id column. You know it's int. But int.Parse can only work on strings, so you are required to turn this object to string, calling its .ToString() method. This will slow down your code insignifficantly on few rows and signifficantly on more rows (few thousands for example).

The following is also wrong:

foreach (DataRow row in dsReportSource.Tables[0].Rows)
{
int iId = Convert.ToInt32(row["id"]);
}

Here you are telling your compiller that you are sure the parameter (row["id"]) will cast to Int32 without problems.
But here you are telling your compiller only 50% of the truth. After you KNOW it is int, just be honest and say:

foreach (DataRow row in dsReportSource.Tables[0].Rows)
{
int iId = (int)row["id"];
}

This applies not only to DataSets but everywhere you have a fixed datatype and you know what the type is.


Don't let your compiler do the work.
Just look at your project and try to find places where you are uncertain about fixed datatype.
Change it to be a direct cast and I am pretty sure you will experience speed improvements.

W3C Zoom CSS property. I really want this feature included!!!

Lot's of people are discussing this.
And the designers are often saying something like:
"I cannot imagine a scenario where you will need to use the Zoom CSS property."
To the readers that haven't yet hit this problem - the CSS Zoom property seems to be proprietary and to be working for IE (I think version 6 and above).

To all those designers - there ARE scenarios where you will want to let the user zoom everything proportionally without using the browser buttons / sliders / shortcuts, but with CSS / JS only.
I will give you few examples:

1. I needed to create an overview control of page. It should represent the page in a smaller percentage and, upon scroll, the page should scroll proportinally. I can have a div with the same DOM tree (or even an IFrame loading the same page or something). In this case I URGENTLY need the CSS Zoom property.
2. Telerik radReporting - the ReportViewer has a dropdown to let the user choose a zoom level to preview the page (web based and not after clicking print preview or something). Actually the Print Preview browser command isn't an option as the report viewer may be on the page with other controls and the user SHOULD BE ABLE to zoom in and out only the portion of the page where the report is (it is an IFrame with the data rendered as HTML, I believe). In telerik case - there seems to be some browser detection and when the browser isn't capable of zooming in / out - the dropdown with the zooming levels is simply hidden (they have no other choice unfortunatelly and I support them for this decision).

Now, as you may expect - in my scenario I cannot simply hide the overview control as the page heavilly depends on it.
Should I now have my revenge now? I've seen all those messages accross the web telling you that there are better browsers to use than IE.
Should I now display a message like:
"Sorry, your browser isn't capable of zooming in and out, only IE supports this, so please switch to IE."

I really hate those browser wars and if you really want to know my opinion - yes, IE may be harder to design. It may be messing up the containers, it may not be passing the ACID N test.
But it is the only browser that is suitable for my scenario (at least from my search in IE all the posts were following the same line - "zoom is IE proprietary, it won't work under other browsers").
Why are all other browsers sleeping then?


P.S. I have found something like -moz-zoom or something but wasn't able to make it work under FireFox (if it works under Firefox it should also probably work under Google Chrome as they are using the same engine I think).
P.P.S. - haven't tested but I think the zoom CSS property should also be available under Opera as they (as far as I know) use the IE core.

P.P.P.S - if anyone know how can we ask W3C to reconsider this for at least the next revision of CSS I would be glad to give my vote. I also advice telerik to do the same. Not only the reporting will work in all browsers but they may be able to do some other great controls using this property.

Really annoying ...

Why your HttpHandler has the Session set to NULL?

I was in a need to create HttpHandler. I also needed to use the session.
Here is my first attempt:

   public class ChbHandler : IHttpHandler
   {
     #region IHttpHandler Members

     public bool IsReusable
     {
        get { return true; }
     }

     public void ProcessRequest(HttpContext context)
     {
        HttpRequest req = context.Request;
        HttpResponse resp = context.Response;
        resp.Write("HttpHandler: Hello World!");
     }
     #endregion
   }

In Here if you try to use the Session object you will not it is null. Why is that?
I googled a bit and found that in order to support session, your HttpHandler should inherit the

IRequiresSessionState or IReadOnlySessionState in order to have the session state in the context parameter (the one that is passed to the ProcessRequest() routine.
Luckilly both interfaces are just marker interfaces, meaning you are not required to implement any additional methods.
So something like this:

   public class ChbHandler : IHttpHandler, IRequiresSessionState
   {
     #region IHttpHandler Members

     public bool IsReusable
     {
        get { return true; }
     }

     public void ProcessRequest(HttpContext context)
     {
        HttpRequest req = context.Request;
        HttpResponse resp = context.Response;
        resp.Write("HttpHandler: Hello World!");
     }
     #endregion
   }

Should work just fine for you.
The only change is : IRequiresSessionState in the list of Interfaces that the class will inherit.

Insignifficant inconvience in telerik radReports

This one is not a big deal but it would be good if there is a workaround.
When you create a new report and choose to create a new datasouce (Database in my case) - the classes will be created in the project root and not where the report is created.
I tried to find some option or something in order to be able to place the datasource in a different folder in my project but with no luck. The datasource was always created in the root of the project.
Here comes the Microsoft part - when you then try to move the classes in another folder (by dragging them in the solution explorer), Visual Studio seems to mess up the namespaces (although I am 99% sure I have moved classes accross the project and the result was I need to manually change the class namespace in order to reflect its path - for example I have been able to move classes from the root folder of the project to let's say a folder named Helpers and I needed to manually change the namespace from ProjectName.SomeClass to ProjectName.Helpers.SomeClass), just can't get it.

It may ofcourse be some of the endless options in the Visual Studio not checked :)
It's kind of pain when you have a large project and want to separate different files according to their role in the project.

radTextBox - get the client ID of the TextBox ...

As the radTextBox should be changing its behaviour depending on the mode in which the developer put it. It doesn't return the ID of the TextBox (I mean the input type="text" id) when you call something like:

rtb.ClientID.

So if you have a radTextBox with the name of

rtbName

You will need to say:

string.Format("{0}_text", rtbName.ClientID);

At least I couldn't find a property to return this information for me.
You can also write a simple extension to do the work for you. Something like:


public static string GetTextBoxID(this RadTextBox rtb)
{
return string.Format("{0}_text", rtb.ClientID);
}

So you can then call it like:

rtb.GetTextBoxID();

Hope it helps ...

telerik radReporting, am I missing something?

I was playing with the radReporting tool. I had a datasource with 1 master item, which has about 2500 child data items.
I was trying to generate a master / detail report with the telerik radReporting.

Here is what I have so far.
First of all - using their videos is a great help. I had everything I needed in order to start.
Second - the designer is really great. I am not designer and it really pisses me off when I had to do any kind of design but with the deep Visual Studio integration and all those little yellow overlap indicators even a guy like me can do the report design.

But then the ultimate test came - the speed.
I want to clarify that I am in the begining and I am more like rookie in the telerik reporting and the reporting at all so it may be my mistake and not their. But I did follow a video to show me how to do the master / details report and I feel I did everything as it was on the video so I was expecting some performance.

Unfortunatelly with the configuration above - 1 master item and about 2500 detail items I had to wait about 5-6 minutes for the report being generated as HTML in the report viewer.
It's OK, I can live with that. There is a lot of data, their matrixes are complex and it takes time to do all the calculations. So 5-6 minutes are OK. Then I selected Rich Text format from the export type dropdown to export my report to an RTF. I was expecting it to pass with the same speed or a bit slower but it took about 25 minutes to load. And sometimes the system was going in out of memory exception...

I wrote my own RTF epxort, which wasn't using telerik radReporting designer but some generations I did instead. I was the one to care about the overall layout. And guess what?
With the remakrs made above (that I need to manually create a class for the report and do the matrixes my way) it took about 10 - 15 SECONDS to load the report. This is about 150 TIMES faster.
When I managed to get a report from the telerik radReportViewer (I needed few tries until the server was in a good enough mood to provide me with one :) it was about 10 MB, while mine which is minimized and set up for just that layout was about 1 MB.

Again - I don't blame telerik as I am not quite sure if I did everything right when I was generating the reports with their designer. I am just learning how to walk in the field of reporting so I may be missing way too much things.
I can only check that my data is comming in 2-3 seconds (so it is not a slow DB issue I guess).
If I am right I may be having an idea that may be considered by them to speed up the performance. I am also now looking if I can connect to some event or override some method that will let me inject my reporting solution instead using their.
If I find a way to do this I will write another post.
If not - I will use telerik radReporting only to open the HTML report in the report viewer and replace the RTF generation with mine so the user can be happy.


Anyone who has some remarks / ideas / help is welcome to comment this post.

Nice example on the Sieve of Eratosthenes algorithm

On the following address you can find a good example on how the Sieve of Eratosthenes works on the first 100 numbers.

http://en.wikipedia.org/wiki/File:Animation_Sieve_of_Eratosth-2.gif

Brief Explanation of the picture:


1. Take the first number (2), it has 2 divisors - 1 and 2 itself. So mark all the numbers that divide by 2 (the red color).
2. Take the next number (3), that is not marked by the previous step (number 3). It has 2 divisors - 1 and 3 itself, mark all the numbers that divide by 3 (green color).
3. Take the next number that is not marked by the previous steps and check if it had exactly two divisors - 1 and the number itself (the chance this number to be prime number is bigger as all the numbers that may be divisors to this number are already marked). Mark all the numbers that divide by the number choosen.
4. Repeat step 3 until the number choosen is less than or equal to the limit you want to find the prime numbers for.


Note : I would like to excuse for my poor scientific english :).

Telerik Style Builder

It is available, yes.
You can test it on the following address:

Telerik Style Builder



I think this is a great service, that will help the collaboration between designers and developers a lot.
Currently only few of the controls have the fine tune interface implemented but I think it is a very good start.

radGrid - check if there was a row selected, before selecting another one [2]

The previous post on this topic was about pointing some solution, which doesn't always work.
I think I was able to identify the problem for this issue.

It is becasue the chain of events is the following when you select a new row:

1. RowDeselected.
2. RowSelecting.
3. RowClick.
3. RowSelected.

I am not quite able to find the logic here.
I think in normal english I should be able to say:

"I am clicking on a row."
"I am in a process of selecting a row." (if not canceled)
"I am deselecting the old row."
"I have selected the new row."

At least the RowClick in my opinion should be fired prior the events described above as it occurs before everything else. You are initiating the above chain of events by clicking on a row so all of them should follow in my opinion.

To me the fact that RowDeselected is before RowSelecting is not such a bad solution. I just can't get why the RowClick is between RowSelecting and RowSelected events.

Any clues?