C# windows application Text Box Enter event problem

Question

2.50/5 (2 votes)

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Hi All,
I m trying to execute the following code in text box enter event

int id;
id = Convert.ToInt32(txtRollNumber.Text);
SqlConnection Con = new SqlConnection(@"Data Source=HORTON-2A5CB16E\SQLEXPRESS;Initial Catalog=Temp;Integrated Security=SSPI;Max Pool Size=100;Connect Timeout=1000");
Con.Open();

but in run time it is showing id = Convert.ToInt32(txtRollNumber.Text); input string is not in correct format
Please help

Thanks & Regards
Indrajit

[added code block for readability]

Posted 12-Apr-11 20:25pm

IndrajitDasgupat

Updated 12-Apr-11 20:29pm

walterhevedeich

v2

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Comments

walterhevedeich 13-Apr-11 2:30am

if your textbox has no value, it will definitely error out.

3 solutions

Solution 2

- check what value u have get on txtRollNumber.Text, it should not be empty

- Use TRIM() to omit the spaces

Posted 12-Apr-11 20:33pm

koolprasad2003

v2

Comments

Sergey Alexandrovich Kryukov 13-Apr-11 2:35am

Trim (not TRIM()) is a good point.
--SA

Tarun.K.S 13-Apr-11 2:53am

Indeed needed but won't solve the problem.

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Sergey Alexandrovich Kryukov · Accepted Answer · 2011-04-12T20:32:00

Solution 1

This is what it is. The text in the text box txtRollNumber should be in integer format: all digits, optional minus, withing the valid range, etc. You need to validate it before converting. Instead of Convert, use int.TryParse(txtRollNumber.Text, out id); this will validate, assign right valued to id in case of success and return Boolean success status.

Use debugger to inspect txtRollNumber.Text before conversion is something is going wrong.

—SA

Posted 12-Apr-11 20:32pm

Sergey Alexandrovich Kryukov

Updated 12-Apr-11 20:34pm

v2

Comments

m@dhu 13-Apr-11 2:38am

This is it. My 5.

Sergey Alexandrovich Kryukov 13-Apr-11 2:41am

Thank you.
--SA

Tarun.K.S 13-Apr-11 2:52am

Совершенный! 5d!

Sergey Alexandrovich Kryukov 13-Apr-11 3:05am

Wow! They finally put charset=utf-8 for a code; I was asking about it so long ago!
The site is certainly improving!
(Recently tried to write something in Chinese but it failed. :-)

Thank you very much for the vote, but...

The word is correct, but the usage is wrong. This word (="perfect", thank you very much) has tens of forms, this is a singular, male gender (matches male gender of the word "Answer" but not "Solution" (middle gender) on the base case (nominative)). Almost there, but in this gender the usage of single word is style stylistically wrong, sounds like Indian accent :-). I suspect it is impossible to learn all that. I can explain and fix each and every case (most Russian people cannot), but would not know how to teach it all.

By the way, the quality of automated translations from/to Russian is a source of permanent jokes. There are collections of the hilarious cases, especially Word "corrections". For example, the Russian word for "multichannel" was not found in the dictionary, the "correction" suggested by Word was: "anal animation". (I can explain why, the Cyrillic spelling of it is really close.) This is not a joke but a real story. When I read about that I checked it up -- exactly so.

--SA

Tarun.K.S 13-Apr-11 3:43am

Ohkay, I think I will learn Russian now!
Lol conversions are quite tough to make considering Russian language.

Sergey Alexandrovich Kryukov 13-Apr-11 4:26am

I once asked one Indian guy who gave who answered a question about Google Translate for English-Hindi. I asked him, you know... is it any serious... he answered: "pretty much acceptable quality". With Russian, it's a rare case, mostly the LOLs.

Hey, did I tell you that story about Russian and Sanskrit?
--SA

Tarun.K.S 13-Apr-11 4:35am

Hehehe! Also its quite tough to pronounce Russian names too.
SA wrote : Hey, did I tell you that story about Russian and Sanskrit?
Nope you didn't. Tell me what is it about?

Sergey Alexandrovich Kryukov 13-Apr-11 5:05am

Yes, yes. We have one specialist in genetics here in Boston, of Russian origin. He is working on haplotype method. Heard about human genome project? The method shows relationships between people and timing with high accuracy. In particular, it confirmed one of several hypotheses of origin of people distributing the languages of so called Indo-European family, some 60000 yr.ago. This scientist insists they should be called arians or pro-arians. The confirmed location turned out to be around modern Serbia, then people moved to south Ural (Arkaim culture) and much later invaded India (Vedic period). Iran was populated by Arian people much later in fact. It was suggested long time ago, that Sanskrit as people know it now is pretty close a much older common "mother language" of all modern languages in the family, including Slavic and Germanic, Latin, etc. As a result, there is noticeable similarity between Russian and Sanskrit (Russian is the least Germanized but most Mongloized from all Slavic languages, has more Ugru and other archaic roots as well). So, this scientist told about his friend from India, a specialist of Sanskrit, who traveled to Moscow for a conference (not speaking Russian) and came to Moscow hotel. The hostess gave him a key and said something like "please, your room 384". The guy was shaken in a shock: he felt she was talking some strange dialect of Sanskrit, but in fact by sheer randomness that phrase was very close to some similar Sanskrit phrase. I don't remember, but is something like Russian 4 ("chetyre") sounded like "chatvari" or like that...
--SA

Tarun.K.S 13-Apr-11 5:33am

Human Genome project yes heard about it a bit. I think they sequenced the whole genetic code and stuff etc. ! I did know that Sanskrit was a very old language and was a base for other languages but this is amazing! WOW!
SA you know so much info about these, truly marvelous!
I have bookmarked this too! :)
Thank you so much for the info, this will be "instilled" in my brain for a long time. :)

Sergey Alexandrovich Kryukov 13-Apr-11 5:51am

:-)

Sergey Alexandrovich Kryukov 13-Apr-11 6:02am

Thank you, but what's so special? I know it from some five articles or so, and they are in popularized form.

No, what I'm talking about is a different part of it, very remotely related to main generics. They found a part on the chromosome which is like a digital signature of a person (inherited by male line). The key is: this info is never translated to phenotype, so it is neutral and not related to any features, hence not to survival. As a result, the mutation speed in this haplotype part is very uniform. There is a criterion of close values in this signature, so if you have two people, one can calculate how many generations ago they had a common ancestor, statistically, of course, but with good accuracy. If one can get many signatures representative in wide range of people of different origin, the history of many ethnic groups and motion of their geographic distribution can be reconstructed. Many facts were already dug out.

--SA

Tarun.K.S 13-Apr-11 6:24am

Wow got to read more about all these stuff. I studied about genes when I was in 10th!
The genes made up of proteins that contains the code which helps for the development of a human being. Man its a very advanced stuff!
But this is amazing, tracing the ancestors to find a common one, cool!
Thanks again for the heads-up!

Sergey Alexandrovich Kryukov 13-Apr-11 6:28am

Now, here is the tough part of it: the articles I mentioned are written in... Russian. Would you like the references? :-)
--SA

Tarun.K.S 13-Apr-11 6:39am

Hahahahhaa! Well once I learn Russian I will surely ask for it! :D

Sergey Alexandrovich Kryukov 13-Apr-11 6:52am

Верной дорогой идете, товарищ!
(I specially tested on Google Translate to English: almost adequate.)
--SA

Tarun.K.S 13-Apr-11 6:58am

Lol it meant : Right way go, comrade!

Sergey Alexandrovich Kryukov 13-Apr-11 7:01am

More exactly, it means "You go the right way, comrade!" This is a memetic one.
--SA

Tarun.K.S 13-Apr-11 7:07am

Роджер что!

Sergey Alexandrovich Kryukov 13-Apr-11 7:49am

First word makes no much sense (transliteration of the name Roger).
--SA

Sergey Alexandrovich Kryukov 13-Apr-11 6:32am

Interesting phenomena: modern biology tends to become informatics. As a result, people with "standard" University education in biology... do not understand biology. I know this by my son and some friends. But I have some better chances to understand it. (But frankly, I don't understand much: what my son tells me about his biochemical matter is like a dark forest for me.)
--SA

Tarun.K.S 13-Apr-11 6:47am

Hmmm Biology is tough too! One has to remember weird names, I as a child liked nature. I used to look under rocks to find earthworms, insects etc. Lol.
So is your son studying Biology in University?

Sergey Alexandrovich Kryukov 13-Apr-11 6:59am

Yes. Some other knowledge they know is my less then I remember from my ordinary school though. I'm the one who remembers maybe many... hundreds of taxons, all those worms and insects... They don't learn it here. But genetics and biochemistry look serious. It also depends on how many courses you can pick.
--SA

Tarun.K.S 13-Apr-11 7:12am

Yeah right!
Cool that you know many things!

Tarun.K.S 13-Apr-11 4:58am

Hey what was the story?!!

Tarun.K.S 13-Apr-11 4:00am

Yesterday was a proud moment for Russia for celebrating the anniversary for Soviet sending the First Man in Space also winning the Space Race! :)
Yuri also visited India 6 months after this remarkable event!

Sergey Alexandrovich Kryukov 13-Apr-11 4:22am

I know, this is great!
--SA

girish sp 13-Apr-11 2:59am

SAK-tryparse is the best one!!my 5..

Sergey Alexandrovich Kryukov 13-Apr-11 3:07am

Thank you, Girish.
--SA

Pong D. Panda · Accepted Answer · 2011-04-12T20:35:00

Solution 3

Hi use this instead,

MIDL

int id = 0;
Int32.TryParse(txtRollNumber.Text, out id);

Posted 12-Apr-11 20:35pm

Pong D. Panda

Comments

Sergey Alexandrovich Kryukov 13-Apr-11 2:36am

Didn't I just said that? Maybe we did at the same time, my 5.
--SA

m@dhu 13-Apr-11 2:37am

How does your answer make any difference with SA's?

Pong D. Panda 13-Apr-11 2:42am

I posted my answer a little too late. Both our solution has the same principle.

Sergey Alexandrovich Kryukov 13-Apr-11 2:42am

Less letters :-) May be it was at the same time?
--SA

IndrajitDasgupat 13-Apr-11 2:41am

Now it is showing "implicitly convert type bool to int"

Pong D. Panda 13-Apr-11 2:42am

What do you have on your textbox?

Sergey Alexandrovich Kryukov 13-Apr-11 2:45am

Add Boolean variable to your answer so OP could understand what's going on!
--SA

Sergey Alexandrovich Kryukov 13-Apr-11 2:44am

Read carefully, look at the signature. The method returns boolean (true if correct format, false if is not, id is out parameter). See my answer.
--SA

Pong D. Panda 13-Apr-11 2:48am

I see, maybe your doing something like this.
id = Int32.TryParse(txtRollNumber.Text, out id);
which is terribly WRONG!
try to use the code above just the way it is.