updating already opened window/form - C# Discussion Boards

S. Senthil Kumar1-Mar-05 17:04

1-Mar-05 17:04

Maybe if I ask it like this… I new the first form of the app with Application.Run then that form news another form. In that second form I press a button that starts an AsyncCallback (from a socket). When that callback calls back it calls back to the (one and only) main thread. Or is it in a new thread?

I guess you got mixed up in terminologies, a callback can occur *on* a thread, it can't call a thread. You are confusing objects with threads, they are independent. For eg

<br />
class A<br />
{<br />
   public void SomeFunc()<br />
   {<br />
   }<br />
}<br />

Now, class A can be instantiated by the main thread and can be accessed from a different thread. Calling a method on the object from a different thread does not mean it is "called on" the main thread.
As for AsyncCallbacks, they are implemented using threads in the ThreadPool, so, to answer your question, no, async call backs don't occur on the main thread, they occur on a thread pool thread.

As for the second part, did you look into inheritance? It is a language feature specifically for the situation where you want a class to do a few operations and other classes to enhance/modify the operations of the original class. In your case, it would be something like

<br />
class MyClass<br />
{<br />
  //your basic methods<br />
}<br />
<br />
class Subclass1 : MyClass<br />
{<br />
   // Enhanced version<br />
}<br />

In the code above, Subclass1 contains all the data in MyClass, plus additional data that you've defined. If the above lines don't make any sense to you, I suggest you read a good "Object Oriented Programming" (OOP) book.

using mc = MyNamespace.MyMainClass;

This is only a shorthand for accessing MyMainClass, instead of typing using MyNameSpace at the top. It doesn't make any difference to the problem you're trying to solve. And you can access only static functions from mc.

Regards
Senthil
My Blog

Re: Basic Thread Questions (LONG)

GhostsOfOrion2-Mar-05 4:17

GhostsOfOrion

2-Mar-05 4:17

Thanks for your time, knowledge, and patience Senthil. You’ve cleared up some confusion for me and I can enjoy my programming experience much better now! Smile | :)

Inherited Forms in Compact Framework

Tristan Rhodes1-Mar-05 7:59

Tristan Rhodes

1-Mar-05 7:59

Can it be done?

I end up with no END of ResX, problems when i try it and it won't display in the designer (displays invalid cast, compiles OK though), but it seems like a reasonable thing to do. I've got a whole bunch of base functionality I want to implement, and if I resort to interfaces, it'll get messy.

Cheers

Overriding Text in UserControl :confused:

_eulogy_1-Mar-05 7:56

_eulogy_

1-Mar-05 7:56

Hi!
I'm currently creating a control that inherits from UserControl, and I seem to have some problems with overriding the Text property. I've added the [Browsable(true)] attribute to make it possible to edit it in the editor, but it doesn't seem like the editor saves the text I enter. The value stays in the input box in the editor but it's not saved in the designer's CS file. I've tried to changed the name of "Text" to "Caption" and that works just great. So it seems like "Text" has some sort of attributes or something that causes this problem... any suggestions?

Re: Overriding Text in UserControl :confused:

spif20011-Mar-05 20:20

spif2001

1-Mar-05 20:20

try with:

[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]

Re: Overriding Text in UserControl :confused:

_eulogy_2-Mar-05 0:33

_eulogy_

2-Mar-05 0:33

Hmmmm.... suddenly it seems to work.. even though I cleaned the solution and rebuilt many times yesterday.. well.. I'll keep that trick in mind though!
Thanx!

Form Designer for Lightweight Framework

Tristan Rhodes1-Mar-05 7:32

Tristan Rhodes

1-Mar-05 7:32

How do i set the form designer to not stick in stuff that causes Lightweight apps to screw up? Relating to an earlier program, all the stuff that crash the system aren't supported by the .net lightweight framework.

So I'd like to turn it off.

Can this be done? Or is there some other solution?

Cheers

Cata

updating already opened window/form

Adnan Siddiqi1-Mar-05 7:09

Adnan Siddiqi

1-Mar-05 7:09

Hello
i am calling a form on each row selection of dataGrid,on every selection its opening new Instance,this can be resolved by using Singleton pattern but is there anyway to update existing instance of form by passing values in Constructor?
one approach i thought to grab the handle of already opened window and close it when new one is opened,but i am unable to fetch old window handled(one way is to store handle value in registry)
is it some nice approach to update existing Form/window?

thanks

<ot>is there any utility which tells running process informations including handles details,kindly let me know

Exporting Crystal Reports To PDF Errors

Khang Nguyen1-Mar-05 7:03

Khang Nguyen

1-Mar-05 7:03

Hello again Gurus,

Whenever I export a report from CrystalReportViewer’s ToolBar to the PDF format, I get this error “Error in File C:\Program Files\MDS\MyReport.rpt: Invalid export DLL or export format.” on the PCs at my work place. It works fine with other exporting formats. It also works fine on my development PC. The app is C# Windows based. Did I miss certain DLLs from the installation package? Thanks for looking into my issue. Appreciate any inputs.

Thanks in advance & happy programming
Khang
Smile | :)

Re: Exporting Crystal Reports To PDF Errors

Raganar1-Mar-05 7:59

Raganar

1-Mar-05 7:59

Go to http://support.businessobjects.com/search/ and do a search on crnet_deployment.pdf. This document tells you how to identify the version of Crystal you are using with your development environment and the corresponding merge modules that should be included with the installation package.

Re: Exporting Crystal Reports To PDF Errors

Khang Nguyen1-Mar-05 8:24

Khang Nguyen

1-Mar-05 8:24

Raganar,
Thank you so much for the tip, Guru! There're always Gurus out there.
Khang
Smile | :)

Attributes property

MyThread1-Mar-05 6:19

MyThread

1-Mar-05 6:19

Hi,

I am trying to write something like this.

m_xyz = m_lbl.Attributes("Name")

where m_xyz is bool and m_lbl is Webcontrols label.

The above works fine in VB.net but gives me the foll. error with C#;

'System.Web.UI.WebControls.WebControl.Attributes' denotes a 'property' where a 'method' was expected

Can you please help me with the above.

Thanks.

Re: Attributes property

Robert Rohde1-Mar-05 6:51

Robert Rohde

1-Mar-05 6:51

The syntax for accessing indexers in C# is different:

<br />
m_xyz = m_lbl.Attributes["Name"];<br />

Re: Attributes property

MyThread1-Mar-05 6:58

MyThread

1-Mar-05 6:58

I found the solution:

m_xyz = Convert.ToBoolean(m_lbl.Attributes["Name"]);

is error free in C#.

Forms in DLL's in .Net Lightweight

Tristan Rhodes1-Mar-05 5:59

Tristan Rhodes

1-Mar-05 5:59

Ok, i just created a form in C#. Ran it on the windows CE Emulator.

Worked fine.

Changed 1 thing in the form. And now, it can't find the InitialilzeComponents() method. It throwns a "MissingMethodException".

Tried re-creating the form, worked fine. Changed 1 thing (different), and it did the same.

Created a dummy method, ran dummy method from constructor. Set up both method calls with breakpoints. Went past dummy, crashed on Component Initialisation. Again.

Copied contents of initialise method into dummy. And it crashed on dummy. Set all internal calls in the dummy method with break points. It crashed somewhere between the Dummy call, and the first break point.

So... i've come to the conclusion my compiler is broke or windows CE is retarded.

How do i fix it? Why is it doing this too me? Is this really something that should be happening?

Cheers

Cata

Update

Tristan Rhodes1-Mar-05 6:03

Tristan Rhodes

1-Mar-05 6:03

Ok, I have just narrowed it down to two calls added automaticaly when you edit the form properties. It's setting the "Name" and "AutoScaleBaseSize" values, which do not exist. Somehow they get past compile time, and into runtime, where it all goes horribly pete tong.

Guess MS need to fix that.

Is this a known problem?

More stuff that cause LightweightFramework to crash.

Tristan Rhodes1-Mar-05 6:39

Tristan Rhodes

1-Mar-05 6:39

More functions that cause the .Net Lightweight framework to crash, that are inserted automaticaly into the InitialiseComponent block.

SuspendLayout()
ResumeLayout()
TabIndex
Name
AutoScaleBaseSize

It all works OK in the design page.

Is there ANY way to stop it doing this? If i add 1 button, i have to delete a whole SLEW of lines of code that are added, and when i discover a new one, I have to comment out a whole block and go through them 1 at a time, uncommenting them. It's driving me INSANE.

*deep breath*
*end rant*

Re: More stuff that cause LightweightFramework to crash.

Dave Kreskowiak1-Mar-05 7:22

Dave Kreskowiak

1-Mar-05 7:22

I haven't had any problems like that. But, then again, I don't think I've ever had SuspendLayout and ResumeLayout in my forms code either. It sounds like Windows Forms (full Framework) code is being generated in place of the code that SHOULD be generated for the Compact Framework.

What on earth did you install?! Big Grin | :-D

This may be an overkill solution, and I would welcome any other suggestions, but I'd try reinstalling Visual Studio. As painful as that may sound...

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Re: More stuff that cause LightweightFramework to crash.

Tristan Rhodes1-Mar-05 7:55

Tristan Rhodes

1-Mar-05 7:55

Yep, I reached the same conclusion, see my next post.

sh!7... I just realised... the DLL i added to my project is not for compact framework, it's raw .Net.

OMG... now i feel stupid.

Never mind... slight 'looser error' as they say. Unsure | :~

Cata

Re: More stuff that cause LightweightFramework to crash.

Dave Kreskowiak1-Mar-05 8:13

Dave Kreskowiak

1-Mar-05 8:13

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Re: More stuff that cause LightweightFramework to crash.

Tristan Rhodes1-Mar-05 10:26

Tristan Rhodes

1-Mar-05 10:26

You seem to know a lot about the lightweight framework. Smile | :)

I've been trying to construct a Form based inheritance tree, but it is refusing to cooperate. Is this functionality not supported in the Compact Version?

Could you offer advice on a good way round it? Because I have some compulsory base functionality that I want to mix with customisable in an inherited class, in a single call. I can't do this with interfaces.

Cheers

Cata

Re: More stuff that cause LightweightFramework to crash.

Dave Kreskowiak1-Mar-05 11:44

Dave Kreskowiak

1-Mar-05 11:44

The Catalyst wrote:
You seem to know a lot about the lightweight framework

Laugh | :laugh:

Very funny!

I've written a couple of applications to toy with it. Nothing more. Form visual inheritance is out of my scope of experience.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Silent console application

Esmo20001-Mar-05 4:21

Esmo2000

1-Mar-05 4:21

If I have a console application that I do not want to be visible, how do I do this? Its being run as a scheduled job, so I cannot run it as a service.

Cheers,
Jim

Treeview question

Aaron Schaefer1-Mar-05 3:19

Aaron Schaefer

1-Mar-05 3:19

Hello All,

I have an app which has a treeview, and I would like to perform a unique action when the user double clicks a leaf node of the tree. I handled the double click event, but this doesn't tell me much. How do I get to the actual tree node (if any) that the user double clicked on?

Thanks

Re: Treeview question

leppie1-Mar-05 3:51

leppie

1-Mar-05 3:51

SelectedNode

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