C# Discussion Boards - CodeProject

Know when data has changed in SQL Server

Rob Ormond3-Nov-09 1:24

3-Nov-09 1:24

Hi,
I have an app that gets data out of the database. This data is updated via a separate application. At the moment the first application has to check every x seconds if there is any new data. I seem to remember reading a while ago something about subscribing to data changes or something so that instead of it being a pull from sql server, sql server actually notifies the app that there is new data and then the app can go get it, and therefore doesn't have to check itself.

Is that right, or did I dream that?

Cheers,
Rob

Re: Know when data has changed in SQL Server

dan!sh 3-Nov-09 1:35

dan!sh

3-Nov-09 1:35

I guess you are looking for SqlDependency or SqlNotificationRequest class.

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Re: Know when data has changed in SQL Server

Rob Ormond3-Nov-09 2:08

Rob Ormond

3-Nov-09 2:08

Ahhh, that may well be it, thank you very much!

Re: Know when data has changed in SQL Server

Md. Marufuzzaman3-Nov-09 6:05

Md. Marufuzzaman

3-Nov-09 6:05

I agree...But i think using a trigger would be a good idea to keep track any alternation / insertion of data.

Thanks
Md. Marufuzzaman

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Re: Know when data has changed in SQL Server

dan!sh 3-Nov-09 16:52

dan!sh

3-Nov-09 16:52

And how would that send notification to front end?

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Re: Know when data has changed in SQL Server

Md. Marufuzzaman3-Nov-09 18:24

Md. Marufuzzaman

3-Nov-09 18:24

so many ways you can do this... But I think your suggestion is excellent regarding this issue.

Thanks
Md. Marufuzzaman

Read SWF WITH C#

zahidhussain3-Nov-09 1:19

zahidhussain

3-Nov-09 1:19

i want to read text of buttons or lables of swf
which is running inside the shockwaveflash control.

Thanks,

zahid

Re: Read SWF WITH C#

Calla3-Nov-09 1:36

Calla

3-Nov-09 1:36

Ok.

Re: Read SWF WITH C#

zahidhussain3-Nov-09 1:40

zahidhussain

3-Nov-09 1:40

how can i do that?

zahid

Re: Read SWF WITH C#

Pete O'Hanlon3-Nov-09 2:05

Pete O'Hanlon

3-Nov-09 2:05

With code.

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What is the equivalant to constant string array in C#?

CelestialCoder3-Nov-09 0:32

CelestialCoder

3-Nov-09 0:32

Suppose I have a byte from USB device which holds the day of the week (1 to 7)
I need to print out Sunday to Saturday based on values 1 to 7. I MCU I create a look up table of strings or string array in ROM and access with index.

What is the method here. I think it is enum. But from tutorials I cant figure out how to get a string from a number like indexing.

Please suggest best way here.

Thanks

With Regards
Roy Thomas

"..this file is known as source file probably because it is a source of frustration and anxiety!" - Chuck Sphar - In book 'C# 2005 for Dummies'.

Re: What is the equivalant to constant string array in C#?

Luc Pattyn3-Nov-09 0:51

Luc Pattyn

3-Nov-09 0:51

Hi,

yes enum is fine since the strings you want are valid identifiers, hence:

enum Days {
    Monday=1,
    Tuesday=2,
    ...
}
public void Test() {
    for (int i=1; i<8; i++) Console.WriteLine(((Days)i).ToString());
}

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Re: What is the equivalant to constant string array in C#?

OriginalGriff3-Nov-09 0:57

OriginalGriff

3-Nov-09 0:57

There are several ways (here are two):

string[] weekdays = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
...
string day = weekdays[3];

enum Weekday
   {
   Sunday = 0,
   Monday,
   Tuesday,
   Wednesday,
   Thursday,
   Friday,
   Saturday
   };
...
string day = ((Weekday) 3).ToString();

No trees were harmed in the sending of this message; however, a significant number of electrons were slightly inconvenienced.

This message is made of fully recyclable Zeros and Ones

Re: What is the equivalant to constant string array in C#?

CelestialCoder3-Nov-09 1:35

CelestialCoder

3-Nov-09 1:35

Thanks a lot to all.

I got it. One clarification.

string[] weekdays = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday" };
...
string day = weekdays[3];

If I use this method, is it creating a RAM string array? or is this array in ROM only? unlike a variable string?

I am using enum .

Thanks a lot

With Regards
Roy Thomas

"..this file is known as source file probably because it is a source of frustration and anxiety!" - Chuck Sphar - In book 'C# 2005 for Dummies'.

Re: What is the equivalant to constant string array in C#?

OriginalGriff3-Nov-09 1:47

OriginalGriff

3-Nov-09 1:47

Depends on your compiler. For Visual Studio, it will always be a RAM string, because it won't let you prefix it with "const" because it is a reference type and it (understandably) won't let you initialize const reference types other than string. Despite it being an array of strings. Grrr.

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Re: What is the equivalant to constant string array in C#?

Luc Pattyn3-Nov-09 1:49

Luc Pattyn

3-Nov-09 1:49

CelestialCoder wrote:
or is this array in ROM only?

on a PC the file system probably resides on a disk, and anything you load from disk is located in RAM; the only thing in ROM (or EEPROM) probably is the BIOS code.

However literal strings belong in code space, not data space. Code space could be write-protected at run-time.

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Re: What is the equivalant to constant string array in C#?

CelestialCoder3-Nov-09 20:30

CelestialCoder

3-Nov-09 20:30

Got it. Thanks for all the info.

Regards

With Regards
Roy Thomas

"..this file is known as source file probably because it is a source of frustration and anxiety!" - Chuck Sphar - In book 'C# 2005 for Dummies'.

Re: What is the equivalant to constant string array in C#?

Hristo-Bojilov3-Nov-09 1:19

Hristo-Bojilov

3-Nov-09 1:19

See Enum.GetValues and Enum.GetNames .

Life is a stage and we are all actors!

DataGridBoolColumn disable CheckBox

kantoz3-Nov-09 0:08

kantoz

3-Nov-09 0:08

Hi,

i have a question about the DataGrid and the DataGridBoolColumn.
Is it possible to disable a CheckBox shown in the DataGridBoolColumn? I get a result of a Database Query. If the Value is true or false the CheckBox should be enabled and the CheckBox is checked correctly, but if the value is NULL the CheckBox ist disabled and checked, i want to get a unchecked and disabled CheckBox in that case.

Thanks for your help!

Re: DataGridBoolColumn disable CheckBox

dan!sh 3-Nov-09 1:30

dan!sh

3-Nov-09 1:30

AFAK you can't.

It's not necessary to be so stupid, either, but people manage it. - Christian Graus, 2009 AD

Visual Studio 2008 cannot detect error

Aftab Sindhi2-Nov-09 23:23

Aftab Sindhi

2-Nov-09 23:23

I am creating a web service project in C#. It has a file containing classes, used by the web service.

Problem 1. When I type a local variable inside the class, it is not showing intellisense. for example I am typing the code for class B, which has local variable for class A. When I am going to type objA (object for the class A) and then DOT (.), class A's members are not displayed.

Problem 2. Inside the web method, if i make typing mistake; i.e. wrong variable name or missing semi colon at the end; still compilation goes successful, while I see, there are errors.

Anybody has experienced this? I am facing this problem 1st time and feel much difficult to continue coding. Please point me to right direction.

Thank you for your help in advance

Regards

Aftab Sindhi
.NET Application Developer
U.A.E

Re: Visual Studio 2008 cannot detect error

freakyit2-Nov-09 23:35

freakyit

2-Nov-09 23:35

hi,

problem1: if your local variable is private you cannot access the var from classB by typing new classA().var .. create a property or declare the variable as public. (i guess that could be a problem).

problem2: you might check whether the class you want to compile has the buildsettings compile or some else..

hope i could help Smile | :)

Re: Visual Studio 2008 cannot detect error

Aftab Sindhi2-Nov-09 23:45

Aftab Sindhi

2-Nov-09 23:45

Thanks for ur reply but it seems u didnt understand my question or may b i could not explain properly. Local variable means variable for instance of class A.

<br />
public class B<br />
{<br />
  private A objA;  // objA is variable name local to class B and is type of A (class)<br />
}<br />

Regards

Aftab Sindhi
.NET Application Developer
U.A.E

Re: Visual Studio 2008 cannot detect error

Luc Pattyn3-Nov-09 0:56

Luc Pattyn

3-Nov-09 0:56

Hi,

make sure the following option is set, using menu Tools/Options/ProjectsAndSolutions/BuildAndRun:
"On Run, when build or deployment errors occur" = "Do not launch"

Smile | :)

Luc Pattyn

I only read code that is properly indented, and rendered in a non-proportional font; hint: use PRE tags in forum messages

Re: Visual Studio 2008 cannot detect error

Aftab Sindhi3-Nov-09 1:13

Aftab Sindhi

3-Nov-09 1:13

Dear Luc Pattyn

Thanks for your reply. I tried that but it didnt solve my problem. I am also observing other behaviors also such as , when I right click on any class, I cant see "View class diagram" menu. Hence I cant create diagram.

This only happens in this project while in same Solution, other project is there, which is not mentioning this problem.

Regards

Aftab Sindhi
.NET Application Developer
U.A.E

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