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Hi,
Im using C# and MS Access,
I was wondering if someone could tell me how to store an object of a class into the database, with an sql query.
My class is variable length so i cant separate its members into columns.
i tried to do this with th ebinary formatter, but it gives an error
Type 'Billing_Module.Bill' in Assembly 'Billing Module, Version=1.0.2924.30808, Culture=neutral, PublicKeyToken=null' is not marked as serializable.
MemoryStream fs = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();
formatter.Serialize(fs, (object)newBill);
fs.Close();
aConnection = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source="+path);
string queryCommand= "insert into BillHistory values ("+newBill.billNumber.ToString()+","+fs.ToString()+")";
can someone help me?
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You need to implement ISerializable[^].
You might want to consider that if your class is changed, will it cause any problems for the saved objects.
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Marking the classes with Serializable attribute should be enough.
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i've had problems in the past where there are events on the object they need to be marked as nonserializable or the app tries to serialise anything that is hooked up to the event.
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You can mark those fields as NonSerialized that you don't want to be serialized.
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This kind of thing always seems like a good idea until you try to maintain it. It would be much better from a normalisation view point to create a database structure to store your data as things like version changes could get you in an absolute mess otherwise.
Failing that implement a custom xmlserialiser for your class so that you can import older versions of the code with just the new properties missing.
Russell
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We can add various controls either using the designer of VS or thru programming/coding.
I want to know:
a) which one is good practice to carry out ?
b) what the difference between them ?
c) Even though we have VS, somtime we design/use control thru coding, why ?
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humdumof wrote: a) which one is good practice to carry out ?
It depends on what you want to do. Adding controls through the designer is great for controls that will always be there (it makes it much easier to modify the controls). Adding controls via code is great if they are dynamic. (Also note that when the designer creates controls it is just writing code for them also)
humdumof wrote: b) what the difference between them ?
There is none. The designer will just write code for you. See the designer.cs file that goes along with your form. You will see that your form is a partial class. You get control over one file, visual studio gets the other.
humdumof wrote: c) Even though we have VS, somtime we design/use control thru coding, why ?
VS cannot do everything. The developers that created it do not (cannot) know everything that you might want to do with forms.
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My best suggestion:
Look at Visual Studio as a productivity tool. If you lean on the designer very heavily, your ability to grasp several concepts might be stunted(delegate registration comes to mind)
I would suggest using Visual Studio to get yourself up and moving....learn the syntax of the language, and then step back a little bit and figure out what exactly it is that the IDE generates for you. Learn the concepts of explicitly declaring your own controls(will probably help you along your way to learning how to develop custom user controls, should you ever need to)....learn how to explicitly register and de-register event handlers.(This is usually your first exposure to delegates in the language) ....and once you get the concepts down, you will realize that the code that VS generates for you is generally very trivial and you can go back to letting it do its thing for you...with the knowledge of what it is doing, you will be able to tweak it if it's "canned" generation is ever not what you actually needed it to do.
"I need build Skynet. Plz send code"
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Is there a IN operator in c#
I need to perform an operation like below:
if (item in Array[]/Arraylist[])
delete item
Regards,
Pavas
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try to use if(array.Contains(item))
My small attempt...
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Ohh yeh, thanks a lot.
Regards,
Pavas
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uhhh......why not just suggest that he use the "in" keyword?
"I need build Skynet. Plz send code"
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Alaric_ wrote: uhhh......why not just suggest that he use the "in" keyword?
What "in" keyword can be used in an if statement?
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I think he's talking about the IN keyword (that he didn't bother reading the docs on) used in Linq.
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Hi all,
I'm using a DateTimePicker Control to select a day (01/01/2008 for example)
is there a way to customise the Date Format so that I can use Relative Date ?
for example today is 03/01/2008 and I want to select 01/01/2008 so I just write -2d (relative date from today)
thanks for any ideas
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that you can simply achieve thru code right?
My small attempt...
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I can't enter (-2D) because the Date format is fixed ("MM dd yyyy" for example)
is there a way to enable editing the Date value without checking the format
or is there a way to create a relative format 
sure when I get -2D in the Value property I can achieve thru code
thanks
modified on Thursday, January 03, 2008 7:13:19 AM
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I am developing a windows application which needs automatic update. Any idea on how to implement this ?
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ClickOnce does that, doesn't it ?
Christian Graus - Microsoft MVP - C++
"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )
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Christian Graus wrote: ClickOnce does that, doesn't it
Thanks, I checked and it does. But I am just trying other way. I will keep a web service which gives update notifications to the windows application. Windows application will download updates and invoke update program(a separate program I will make). This new program will close current running application and update the exe's with new one downloaded, and restarts the application. Do you think it's a fair idea ?
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it's not going to work under vista. It is however how i used to do stuff prior to things like ClickOnce.
I guess even on vista you could call an update exe in your install root requesting elevated priviledges and then quit. This would leave the update exe able to copy over your old exe. You'd also need to think of a way of replacing the updater if the code in there needed replacing.
What will you do about things like host file redirects to ensure that malicious software doesn't use your update service to get a payload onto the machine?
The app i'm currently working on is the kind of app that the network admins would go nuts if we caused an update without telling them so we provide a message in program telling them to run an update at their own convenience.
It's such a shame that user's can't add repositories to windows update like you can in yum or aptitude, it would be so good to have a central updating system that could be controlled by net admins etc; on the plus side we got a round start button and glass effect windows so i suppose we shouldn't complain.
Russell
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Thanks Russel. So ultimately you suggest ClickOnce ?
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Vasudevan Deepak K wrote: http://windowsclient.net/articles//appupdater.aspx[^]
Thanks Vasudevan. That was helpful.
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