WilsonDotNet Forums : C# Specific

The 'Default' column is a keyword in C#

Mon, 26 Mar 2007 19:34:16 GMT

Is the problem with the ORHelper or CodeSmith templates that are generating C# code, or with the ORMapper itself? I can imagine that the ORHelper, and maybe even the CS templates, don't handle this situation, but I don't think the ORMapper would have an issue with this. If it is the generated code, then you can either change the generated code to not be using the keyword (or put it in []), or you can change the database field to avoid the problem. You can also change the code generation of the ORHelper or the CS templates without too much effort. But if the problem is the ORMapper itself then please provide me with more details as I'm not sure how this would be a problem.

Thanks, Paul Wilson

The 'Default' column is a keyword in C#

Mon, 26 Mar 2007 19:30:15 GMT

Hi guys,

I'm trying out the ORM mapper on a small application. However I've come up my first obstacle and that is default (the column of one of my tables) is a keyword in C#. Is there a way around this? Does this I mean I need to change the column name in my table?

Thanks guys

.Net Remoting

Tue, 31 Oct 2006 14:56:19 GMT

Hi Hari:

You have misunderstood. A MarshalByRefObject is a reference to the actual object, not a new copy -- thus there is a lot of overhead and it only works with remoting. I believe that you can of course configure the actual behavior depending on how you have remoting setup, but its been a while since I've thought about that.

Thanks, Paul Wilson

.Net Remoting

Tue, 31 Oct 2006 14:51:13 GMT

Hi Wilson,

I understand whenever we return a MarshalByRefObject from a server-side method, we are actually creating an object which behaves like a CAO and should therefore be avoided. I am hosting a remote object on IIS "ObjectOne"(SAO, SingleCall). Call to a method "MethodOne" of the remote object returns another MarshalByRef object "ObjectTwo".

ObjectTwo.MethodTwo() ... works fine.

Now I reset IIS. and it restarts successfully.

Now only ObjectTwo = ObjectOne.MethodOne() works fine but ObjectTwo.MethodTwo() returns the following exception. Can you please let me know if there is a way to make the

ObjectTwo.MethodTwo() work before calling ObjectTwo = ObjectOne.MethodOne() again.

Thank you very much for your time.

Sincerely,

Hari

System.Runtime.Remoting.RemotingException: Requested Service not found

Server stack trace:

Exception rethrown at [0]:
   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)
   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
   at MyTestRemObj.Order.GetPrice(String clientstr)
   at GenFav.MyHtmlFavorites.CallRemoteMethod() in C:\MyPrograms\MyCSharp\GenFav\GenFav\MyHtmlFavorites.cs:line 171

serial ports

Fri, 21 Jul 2006 00:48:39 GMT

Hi Joe:

I have no idea why they would refer you to my blog, other than that I have mentioned that .NET v2.0 now includes serial ports -- see the System.IO.Ports namespace. And if you're using .NET v1.*, then you'll simply have to use a 3rd party library -- and there are several.

Good luck, Paul Wilson

serial ports

Fri, 21 Jul 2006 00:43:37 GMT

Dear Sir

I am looking for information on how to initialize and use serial ports using c#.

I contacted Dietel.com and they refered me to your blogs. I am new to C# and have not yet discovered all there is to know about adding classes. Can you point me in the right direction for setting up the serial port and reading and writing to it?

thanks

Joe

jlhold@bellsouth.net

Generics

Wed, 26 Oct 2005 11:06:17 GMT

Ignore my response then. :)

Generics

Wed, 26 Oct 2005 11:05:14 GMT

What is the exception message that you are getting in the first line (which sounds like it would be the cause of the second)?

Are you using .NET v2 Beta 2, RC, or some other version? Are you using the ORMapper v4.0, 4.1, or 4.2 .NET v2 binary? Have you compiled it yourself (with any compilation constant changes), or are you using the pre-compiled binaries? Those questions are important since v4.0 and 4.1 were compiled with Beta 2, while v4.2 was compiled with what is essentially the RTM (and should be RC compatible). You need to compile v4.2 with the V2BETA2 compilation constant if you want to run it against Beta 2.

If nothing else, I'll need more details and code -- the more the better so that I can reproduce it, or help you.

Thanks, Paul Wilson

Generics

Wed, 26 Oct 2005 10:59:15 GMT

Guess I just needed some one to chat too! I forgot to change my connectionstring connecting to wrong sql server!

All fixed :) Now I can use generic methods to return sets of entities! ..now on to the next hurdle.. :)

Mark

Generics

Wed, 26 Oct 2005 10:55:55 GMT

Disregard first error in previous post. I fixed the mapping issue.

Still getting type initialization exception.

Mark

Generics

Wed, 26 Oct 2005 10:31:19 GMT

Hi Paul,

I'm attempting to create a GenericDAL setup like this one for hibernate http://www.hibernate.org/328.html but using .net 2.0 and your mapper.

I get everything to compile fine but get an error at runtime. I think it's due to using an open contructed type.

The piece of code:
ObjectQuery<T> query = new ObjectQuery<T>(string.Empty, sortClause);
return DataManager.ObjectSpace.GetObjectSet<T>(query);

The first line causes Wilson.ORMapper.ORMapperException. The second causes System.TypeInitializationException.

What am I doing wrong?

Finding Difference two Dates

Fri, 14 Oct 2005 18:17:56 GMT

Is there a question here ?

Thanks, Paul Wilson

Finding Difference two Dates

Fri, 14 Oct 2005 13:59:25 GMT

//taking one date
string oldDate= "15-08-1980 08:00:00";

//parsing the date
DateTime dt1 = DateTime.Parse(oldDate);

//taking current date
DateTime dt2 = DateTime.Now;

TimeSpan diff1 = dt2.Subtract(dt1);

DateTime finaldt = new DateTime(diff1.Ticks);

//displaying the difference in year, hour, days
Console.WriteLine(finaldt.Year);
Console.WriteLine(finaldt.Hour);
Console.WriteLine(finaldt.Days);

Generics

Thu, 01 Sep 2005 10:21:42 GMT

Thanks, that's just what I needed.

Generics

Wed, 31 Aug 2005 18:20:47 GMT

Instead of:

ObjectSet contacts = Manager.GetObjectSet(typeof(Contact), string.Empty);
Contact contact = contacts[0] as Contact;
Detail detail = contact.Details[0] as Detail;

You can use:

ObjectSet<Contact> contacts = Manager.GetObjectSet<Contact>(string.Empty);
Contact contact = contacts[0];
Detail detail = contact.Details[0];

And that's really the type of difference that is consistent throughout -- you specify the generic type in both the object declaration and the usage, but you no longer have to use typeof() to specify types and you won't have to cast things. If you need more then give me a little more idea of what you are looking for in particular.

Thanks, Paul Wilson

Generics

Wed, 31 Aug 2005 16:09:17 GMT

Can we get an example or two of using generics?

Strange "using" syntax

Sun, 21 Nov 2004 14:14:22 GMT

Hi TK:

An object is "earmarked" for cleanup as soon as it leaves scope, but it is NOT disposed automatically -- at least not unless you use the using syntax. Objects that hold critical resources, i.e. resources that need to be released as soon as possible, typically implement the IDisposable interface so that you can know that you should call the Dispose method when you are done with them. If you do not do this then you are (1) waiting for the garbage collector to cleanup the object and you are (2) assuming that the object had a finalizer that will do the cleanup if its unmanaged resources. Both of those things are very bad -- waiting for the garbage collector can take far too long when its a critical resource, even longer if the cleanup must occur in a finalizer, and some objects do NOT even implement the correct cleanup code in finalizers since they assume you will call Dispose. What's an example? Database connections, file handles, socket connections -- anything that is limited and typically not managed. Garbage collection by itself only cleans up the memory associated with an object, leaving the other resources that need to be cleaned up to the implementer -- and even then if you wait for such cleanup in the finalizer than you can be waiting a long time due to the non-deterministic finalization process.

Thanks, Paul Wilson

Strange "using" syntax

Sat, 20 Nov 2004 22:44:27 GMT

What is an example of when you would need that? If you instantiate an object in a method, it gets disposed and earmarked for cleaup as soon as you leave scope.

If you wanted to take an object of the heap, wouldn't...

oMyObject = null;

do the trick?

Isn't

using (CreateDevice frm = new CreateDevice())
{

}

Just way way of defining a smaller than method scope, scope?

TK

location of "new MyStruct()"

Sun, 22 Aug 2004 06:18:58 GMT

I'm not sure why you think there is silence on this basic issue -- its pretty explicitly stated in the docs (see http://msdn.microsoft.com/library/en-us/csref/html/vclrfnewoppg.asp) and very widely understood. The statements "int i = 0;" and "int i = new int();" are equivalent -- they both create new instances of a value type on the stack -- and structs are value types. Of course, where things get complicated is if your struct contains reference types -- then the struct itself is still on the stack, but the reference types it contains are still just pointers to locations on the heap.

Thanks, Paul Wilson

location of "new MyStruct()"

Sun, 22 Aug 2004 01:19:28 GMT

All the literature I've seen says structs are kept on the stack, yet utter silence prevails on what "location" is meant by this statement:

MyStruct aStructInstance = new MyStruct();

After this statement, is "aStructInstance" still on the stack? Has it been boxed and now exists on the heap?

Another way to have asked this question is this: does operator "new" ALWAYS fetch memory on the heap, or does it have other overloaded purposes?

ArrayList cast

Fri, 20 Aug 2004 13:53:11 GMT

I think I found the problem. The section of the method I had commented with "/*yadda yadda*/" contained a conversion of SqlDateTime to System.DateTime.

The call stack dump that accompanied the error fingered that as the problem, but being tired (and thinking the call stack would not reveal any useful info in this case) I didn't bother to look beyond the prima facie pinpoint of the ArrayList code principally fingered in the error. An important lesson was learned here.

So now I'm off to find the cleanest way to transform a SqlDateTime into a System.DateTime.

Thanks,

Brent

ArrayList cast

Fri, 20 Aug 2004 03:41:25 GMT

It works for me, so I'm not sure.

Thanks, Paul Wilson

ArrayList cast

Fri, 20 Aug 2004 00:33:23 GMT

My ASP.NET application gives the error:

"Specified cast is not valid."

It points to the ArrayList assignment below:

//declarations
Attach Schedule;
ArrayList SchedList;
//execute
Schedule = new Attach();
SchedList = new ArrayList(Schedule.GetEvents()); <==HERE

The function "Schedule.GetEvents()" is defined in class "Attach" as:

public ArrayList GetEvents()
{ ArrayList fooArrayList = new ArrayList();
/*yadda yadda*/
return fooArrayList;
}

I don't see what the problem is. Suggestions?

Windows Forms

Sun, 08 Feb 2004 21:52:46 GMT

Thanks Mr.Paul

Windows Forms

Fri, 06 Feb 2004 03:57:58 GMT

Hi Jagan:

WinForms in .NET fully support true visual inheritance like you desire, unlike WebForms. VS.NET even makes it easy by allowing you to pick new Form or derived Form, in which case you get a dialog to pick the base Form. I don't have VS.NET in front of me right now for the exact wordings, but it should be easy to find. There are also several articles and blog entries I've seen about visual inheritance, but I didn't keep up with them since it mostly just works, but a google search should turn them up.

Thanks, Paul Wilson

Windows Forms

Thu, 05 Feb 2004 20:14:18 GMT

i have one common window form. I Want to inherit from that common window. Inherited window form, i need to place some new controls with inherited one.

Please let me know the way of doing that inheritance.

Thanks & Regds,
Jagan

DLL equivalent

Fri, 05 Dec 2003 03:43:09 GMT

VS allows you to have multiple projects inside a single solution. Each application corresponds to one dll (or assembly). You typically have just one main GUI project (web or windows), with other projects being class libraries or control libraries.

Thanks, Paul Wilson

DLL equivalent

Thu, 04 Dec 2003 21:51:30 GMT

For a C++ project, it is possible to reference several DLLs that you are building in the same workspace. If designed correctly (COM comes to mind), a single DLL could be altered, rebuilt and essentially copied over the old one and the executable system that uses that DLL would never know it. When the main application is re-run, though it itself was not recompiled, it gains the newer functionality provided by the DLL that was rebuilt.

What is the equivalent in C#? In Visual Studio how do I divide my application into seperate, er, um, DLLs? Perhaps the term nowadays is "assembly?" Checking the project properties, the only obvious item to fiddle with is "output type" of which one selection is "class library." Is this what I'm looking for?

accessing form elements server-side

Thu, 11 Sep 2003 19:25:37 GMT

Hi Sara:

You are approaching the problem from the wrong end. Don't try to validate what the user enters since there is not something wrong from their point of view. Instead, deal with this in your data access layer. A common solution is to use stored procedures and parameters, which nicely does away with the problem. Another solution is to have a data access method that wraps this replacement that you use all of the time.

Thanks, Paul Wilson

accessing form elements server-side

Thu, 11 Sep 2003 19:20:22 GMT

Hello,

I have a user-registration form with numerous fields for input. I am using the asp.net validation controls to validate most of the fields. I haven't found one to suit the following purpose:

I need to ensure that if the user enters in an apostrophe, that i can replace that with two aposrophes so it goes into the database okay.

I have tried using a loop as such:

for (int i=0; i < Request.Form.Count; i++)
{
Request.Form.Get(i).ToString().Replace("apostrophe", "double apostrophe");
}

This does not work for me. I am using the code-behind method to store my logic.

I would like some way to access the current form, rather than the the one in the Request object. I am of course able to access the fields individually by name, but I have 40 controls and thought it would be cleaner to just write a
function that looped through them all. Then I can also allow for code re-use.

I hope I am being clear in what I am looking for, I have spent too much time trying to figure it out. Now I need help!

Thank you for your time,

Sara

Strange "using" syntax

Sun, 06 Jul 2003 07:48:38 GMT

MSDN states:

"The using keyword has two major uses:
using Directive - Creates an alias for a namespace.
using Statement - Defines a scope at the end of which an object will be disposed."

You are probably familiar with the first use which is common at the beginning of nearly all C# classes.

The case you are now seeing is the second use which is not at all related to the first usage you're familiar with. Think of this use of "using" as a quick way to code a try/finally block where Dispose is called in finally.

Thanks, Paul Wilson

Strange "using" syntax

Sun, 29 Jun 2003 22:02:41 GMT

I'm looking at some sample code that has this line:

using (CreateDevice frm = new CreateDevice())

...I know what "using" is for and what it does, but placing the assignment statement inside of it is strange to me. Whats going on here?

(yes, by the way, the sample from whence this snippet came does compile and run)