Re: Using Threads in Windows Forms - C# Discussion Boards

But_Im_a_Lady23-Jul-08 0:58

23-Jul-08 0:58

Hi,

I am 2 months into a new job and I have been looking at the structure of the main solution here, and one thing that puzzles me is the complete lack of any standards Confused | :confused:

2 questions I have are to do with USING directives:-

EG at the top of all of the forms is : using System.Windows.Forms;

but everywhere within code the whole name is qualified e.g :-

private System.Windows.Forms.TabPage tabCustomer;
this.tabCustomer = new System.Windows.Forms.TabPage();

1) Does this have any extra overhead with regards to performance?
2) Also, is it good practice to ensure that any namespaces are declaring at the top of the code?

Thanks in advance.
Janet

Lady Programmers are a rare breed!

Re: using Directive clarification

Luc Pattyn23-Jul-08 1:06

Luc Pattyn

23-Jul-08 1:06

Hi,

Visual Studio generates a couple of using statements automatically when
creating a new C# file.

The Visual Designer always generates code with fully qualified type names,
so no ambiguity can creep in.

Some people insist on not using using statements at all, and always have fully
qualified type names.

But as a programmer you are free to use or not use using statements, and to use or not use
fully qualified type names, as long as the compiler can find them and find them
without ambiguity.

There is no performance difference whatsoever.

Smile | :)

Luc Pattyn [Forum Guidelines] [My Articles]

Voting for dummies? No thanks. Dead | X|

Re: using Directive clarification

But_Im_a_Lady23-Jul-08 1:11

But_Im_a_Lady

23-Jul-08 1:11

Thanks for the prompt reply

glad to here there are no perfomance issues.
I have to admit that code is far easier to read without fully qualified type names.

Cheers again,
Janet

Lady Programmers are a rare breed!

Re: using Directive clarification

Luc Pattyn23-Jul-08 1:27

Luc Pattyn

23-Jul-08 1:27

You're welcome.

But_Im_a_Lady wrote:
code is far easier to read without fully qualified type names.

That may change when your programs becomes very large though. Big Grin | :-D

Luc Pattyn [Forum Guidelines] [My Articles]

Voting for dummies? No thanks. Dead | X|

Using Threads in Windows Forms

Megidolaon23-Jul-08 0:35

Megidolaon

23-Jul-08 0:35

I have a program that tests DB tables. As these tests can take up to several minutes, I want to outsource them into other threads, to at least give the user to possibility to abort them/exit the application.
It's not intended that the user can execute several tests at a time, so I actually only need the main thread in which the Windows Form is running and a single worker thread that performs the test.

My main problem is that I run the test table by table in a loop and each time a table has finished testing, several dictionaries and controls are updated.
When the tests is performed by another thread, it means that the user can access the same dictionaries the testing thread is updating.

So far I just tried to get the testing thread running and allow the user to abort it but I didn't have much success yet.
I used the Windows Forms Invoke Method but that doesn't seem to help much, as the GUI still doesn't respond until the test is finished.

Could you tell me what approach would be best?

Should I use a ParameterizedThreadStart that gets passed a list of all dictionaries?

And how would I go about updating the Windows Forms controls? Create some event that is fired when a table has finished testing?

Thanks in advance.

Re: Using Threads in Windows Forms

DaveyM6923-Jul-08 0:53

DaveyM69

23-Jul-08 0:53

Have a look at the BackgroundWorker component.

Dave

Re: Using Threads in Windows Forms

MrKalinka23-Jul-08 1:00

MrKalinka

23-Jul-08 1:00

You could try to use the System.ComponentModel.BackgroundWorker class. The DB access takes place in an DoWork event handler.

For more information take a look at MSDN[^]

Hope this will help you.

PS: DaveyM69 was faster :=)

Re: Using Threads in Windows Forms

Megidolaon24-Jul-08 4:28

Megidolaon

24-Jul-08 4:28

Thanks!
I've tried it and it seems the BackgroundWorker is indeed a good solution.

It's just a hassle, because during the test the worker thread needs to access a variety of lists and update several controls on the form.
I'm using ArrayLists as arguments to provide data for the worker thread and send the results of it to the form.

It's a bit awkward as I have to cast not only the argument object but also the content, is there any better solution that is more type safe?

Re: Using Threads in Windows Forms

DaveyM6925-Jul-08 11:50

DaveyM69

25-Jul-08 11:50

Maybe create a class of data types/objects that may need to be passed back and report that object to the main thread. Just one cast will be needed then.

Dave
BTW, in software, hope and pray is not a viable strategy. (Luc Pattyn)

Re: Using Threads in Windows Forms

Megidolaon29-Jul-08 21:46

Megidolaon

29-Jul-08 21:46

There still is a little problem left, I'd appreciate if you could help me out again.

I was wondering whether or not a BackgroundWorker thread releases the locks on objects it held while doing the work, if it is canceled.

If not, is there a way to release the locks without using Monitor.Exit or using that method after I verified that the thread still owns the lock on the object?

pivot table not showing any data

Shuaib wasif khan23-Jul-08 0:18

Shuaib wasif khan

23-Jul-08 0:18

ia m using pivot table in my c# application
my code is

SqlConnection cn=new SqlConnection("database=durdu;user id=sa;pwd=");
SqlDataAdapter cmd=new SqlDataAdapter ("select * from marksheet",cn);
DataSet ds = new DataSet();
DataTable dt=new DataTable();
cmd.Fill(ds);
dt = ds.Tables["Marksheet"];
axPivotTable1.DataSource=(msdatasrc.DataSource)(object)dt;

i have a problem because my pivot table does not show any data

is this a correct way i am bindind data to a pivit table or

what can i do to bind data in pivot table.

please provide me any code example how to bind data in a pivot table

thanks in advance Sleepy | :zzz:

Repost of earlier questions.

Pete O'Hanlon23-Jul-08 2:09

Pete O'Hanlon

23-Jul-08 2:09

Please stop posting the same question. You've asked the same question 3 times in the last 24 hours, and have ignored the replies you already had. I suggest you revisit your earlier[^] questions, rather than opening up new ones.

Deja View - the feeling that you've seen this post before.

My blog | My articles

XML comparision

Princeyuva23-Jul-08 0:16

Princeyuva

23-Jul-08 0:16

How to compare two XML Files and generate the differences in a third file...

say for example...

string sXMLContent1;
string sXMLContent2;

I want to compare these two XML contents. NOTE: i don't want to use string.compare function. i want to check all the sub nodes. and write the difference in a out put file.

Your thoughts are higly appreciated. I want to do it in C#

Thanks,
Prince

Re: XML comparision

led mike23-Jul-08 5:03

led mike

23-Jul-08 5:03

Maybe you can use the XML Diff and Patch tool[^]

led mike

checked dateTimePicker

kaustavG23-Jul-08 0:13

kaustavG

23-Jul-08 0:13

Hi all.......
I have to put a checkbox in a DateTimePicker. My idea is whenever I check the checkbox the datetimepicker will be activited and will be disabled otherwise. if anybody knows the solution plz help me out. thanks

Best Wishes
Kaustav Ganguly
Mindteck India

Re: checked dateTimePicker

DaveyM6923-Jul-08 0:19

DaveyM69

23-Jul-08 0:19

How about making a user control? Add a DateTimePicker and a CheckBox and in the CheckedChanged event

dateTimePicker1.Enabled = checkBox1.Checked;

Dave

Re: checked dateTimePicker

Aaron849823-Jul-08 5:27

Aaron8498

23-Jul-08 5:27

DateTimePicker.ShowCheckBox = true;

retrieving the flag value of one form in other

preetpal23-Jul-08 0:00

preetpal

23-Jul-08 0:00

i have declared an object of a form in other form for accessin a flag value. but it is not able to access it.

Re: retrieving the flag value of one form in other

DaveyM6923-Jul-08 0:12

DaveyM69

23-Jul-08 0:12

There are several ways to do this.

The best way is to create an event in the second form (FlagChanged) that can be listened to from anywhere - including the first form.

Second best is to create a class (FlaggedForm) that inherits from Form and add the Flag property to your class.

There are other much dirtier methods (that I won't mention!)

Dave

Re: retrieving the flag value of one form in other

Elroy Dsilva23-Jul-08 0:57

Elroy Dsilva

23-Jul-08 0:57

If you are talking about that flag being not accessible, the closest thing I can suggest is that you have a look at its access modifier, should be public.

Glade , monodevelop or sharpdevelop

adnane22-Jul-08 23:58

adnane

22-Jul-08 23:58

Hi,

i want know if glade, sharpdevelop or monodevelop can do some applications (in mono) that have an interface like media center.
what the pertinent IDE can i use for that goal
thanks Smile | :)

Soufiane

Re: Glade , monodevelop or sharpdevelop

Simon P Stevens23-Jul-08 1:57

Simon P Stevens

23-Jul-08 1:57

The easiest IDE to do it in would be visual studio 2008 (There's a free express edition), and using WPF.

mono doesn't support WPF yet though, so might not be any good for you.

I'm assuming then that you're talking about a win-forms app. Any IDE will do for this (think VS2008 is probably still the best), But it's going to be a lot of manual/owner drawn controls, it's not the easiest thing in the world to do. It's certainly not do-able just by pointing and clicking your way through it. Probably best to look for some 3rd party skinable control library.

Simon

Re: Glade , monodevelop or sharpdevelop

adnane24-Jul-08 9:37

adnane

24-Jul-08 9:37

hi,thanks for the answer, but the probl that i must work in UNIX
do u have a solution? $Shucks | :-\$

Soufiane

Re: Glade , monodevelop or sharpdevelop

Simon P Stevens24-Jul-08 10:34

Simon P Stevens

24-Jul-08 10:34

Well if you have to do the work in UNIX just pick one of those IDEs, they're all gonna give you about the same levels of support I would assume. A media player like interface is going to pretty much have to be all owner drawn, so you're going to spend a lot of your time writing graphics code to draw all the pretty shapes.

There isn't a simple point and click interface for this kind of custom fancy stuff.

That or find a 3rd party control library that works on mono, and has skinable controls.

Simon

MAGIC: modifying a class memeber affects another member, HOW?

Muhammad Gouda22-Jul-08 23:43

Muhammad Gouda

22-Jul-08 23:43

Here is the code:

public Document(string title, string source,string summery, string [] filesList, int noOfFiles)
		{
			this.title = title;
			this.source = source;
			this.summery = summery;
			this.noOfFiles = noOfFiles;
			this.filesList = filesList;
			this.pathsList = filesList;
			
			string [] temp; 
			
			for(int i=0; i<noOfFiles; i++)
			{
				temp = pathsList[i].Split('\\');
				this.filesList[i] = temp[temp.Length-1];
			}
		}

the array pathsList holds the full path of the files
the array filesList hold the abstract names of the files
As you see in the code, in the loop I update only the filesList
The MAGIC is, the pathsList is updated too
Can any why tell me how this happens?

Mohammed Gouda
foreach(Minute m in MyLife)
myExperience++;

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