How to open last form on startup - C# Discussion Boards

WebBrowser 2.0 in Multithread application

15-Apr-07 11:15

The data is wrong. What else can we say ? We need to see your code, and see the data you're pulling in, for us to tell you what's wrong with it.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog
"I am working on a project that will convert a FORTRAN code to corresponding C++ code.I am not aware of FORTRAN syntax" ( spotted in the C++/CLI forum )

cardy115-Apr-07 8:55

cardy1

15-Apr-07 8:55

Hello! I'm having a lot of problem using the WebBrowser in VS2005. Surfing the web, I learnt that this component is only a wrapper of the active-x component of Internet Explorer. Is impossibile to use this in multithead applications.
I listened that the reason is because each instance of WebBrowser refers to the same object and it could process one request at time (single-thread use only). Mad | :mad:

I have a form called "formA" that is my main form and another form, called "formB"that is the form wh0o contains the WebBrowser . When a particular event occurs in my app(formA) I need that a new formB is launched (shown) in a new thread,more than once.
Instead of multiple formB I see only once of all, and i see the new one only when I close the previous one.
Ex:

<br />
public void FormA_custom_event(){<br />
Form B=new FormB();<br />
Thead t=new Thread(new ThreadStart(B._ShowDialog));<br />
t1.Start();<br />
}<br />
[...].br />
<br />
//FormB.cs<br />
//I need to use a method with the void signature to run in the thread<br />
//I need to use the ShowDialog() instead of the Show() method because else the thread will terminate immediately after the call of Start() method<br />
<br />
public void _ShowDialog(){<br />
this.ShowDialog();<br />
<br />
}<br />

I apoligize for my bad english but I'm Italian ;Pand my english is really poor. I hope that someone can help me because I'm gettin crazy... Thanx for any reply.;)

Luc Pattyn15-Apr-07 9:26

15-Apr-07 9:26

Hi,

the WebBrowser documentation states:
The WebBrowser control is resource-intensive. Be sure to call the Dispose method when you
are finished using the control to ensure that all resources are released in a timely
fashion. You must call the Dispose method on the same thread that attached the events,
which should always be the message or user-interface (UI) thread.

So you should not create additional threads for this. Instead, create as many forms as
you want, keep them alive (e.g. by adding them to an ArrayList), and use Show()
instead of ShowDialog(). The forms will remain open until you Close() them (after
which you should remove them from the ArrayList, so they can be garbage collected).

Smile | :)

Luc Pattyn

[My Articles]

cardy115-Apr-07 10:18

cardy1

15-Apr-07 10:18

Sorry,but I need multiple istances of my form that running of different threads.
My application should be a client-server chat. My client application has 2 threads: one to send message and the other one to receive messege. Anytime my application receive a message from a user a new form(formB) must appear if the conversation window for that determinated user is not already opened... and if I lunch the new conversation form from the same thread that execute the receive routine, the application goes into a busy state and I have to close the program. I hope you have understood me... Confused | :confused:

Luc Pattyn15-Apr-07 11:35

15-Apr-07 11:35

Sure, but you cant put a WebBrowser on those forms that are running on another thread...

Luc Pattyn

[My Articles]

How to open last form on startup

cardy125-Apr-07 3:41

cardy1

25-Apr-07 3:41

i found a really simple solution that seems working..I've used another thread that checks the boolean value of a var.If true launch new form. When I have to launch my instances of form containing WebBrowser component I change the value of the boolean and it works... Thanx to all the people tryed helpin' me...;)

AndrusM15-Apr-07 8:07

15-Apr-07 8:07

I have WinForms MDI application.
MDI child forms are created by menustrip click enent handler

AppDesktop.FormMgr.Show(new ChildForm1("param1", "param2") );

Every MDI child form "childform1" may have separate class with different name and different number of parameters.
When application in opened, last MDI child form must be opened automatically.
I think I must store last opened form name to isolated storage and call

AppDesktop.FormMgr.Show(new LastOpenedForm(lastParam1, lastParam2) );
Reflection should probably used to make this call.

Any sample code or idea to implement this ?

Andrus

Christian Graus15-Apr-07 11:28

15-Apr-07 11:28

You don't need reflection, you just need to store the state of your form somewhere, and use that data to recreate it. It depends entirely on what the form could be, as to what yuo need to store.

AndrusM15-Apr-07 11:52

15-Apr-07 11:52

Thank you.
My forms contain data bound DataGridView.

My form restores its state when is opened.
Only thing i need is to create last form at starup.

Any idea how to implement this ?

Andrus

Christian Graus15-Apr-07 12:02

15-Apr-07 12:02

It seems likely to me that what you need to do then is store your data source, so you can rebuild the form with the same data.

AndrusM15-Apr-07 12:12

15-Apr-07 12:12

I have code in Load event which restores form data, position etc. This is OK.

My question was about creating this form at application startup: How to store form name and parameters and most importan, how to use this to re-create form creation command.
I have different classes for every form so I know the form name only as string at startup.
There are hundreds of forms and it is difficult to use switch statement to invoke form my its name.
I need to create form whose name is given as string.

Andrus

Christian Graus15-Apr-07 12:21

15-Apr-07 12:21

OK, I didn't realise you had hundreds of form types in your app, isn't that a little unusual/confusing ?

In that case, your options are a switch statement, or making sure that each form type has a constructor that will build to what you want, then you may be able to use reflection to invoke a constructor with the parameters you have stored.

AndrusM16-Apr-07 5:05

Re: C# Asynchronous Sockets

16-Apr-07 5:05

Christian Graus wrote:
you had hundreds of form types in your app, isn't that a little unusual/confusing

Thank you for excellent question. I'm converting existing ERP application to C#. It has forms for customer, invoice, item, payment term, order, offer etc. etc. database contains 500 tables.
I think that this is very common.

I think I can add some code to form base class constructor for this which stores child form name in isolated storage.

Switch statement is too big for this and so it is ugly.
Based on your responses I think about the following approach:

1. Retrieve actual calling class name from base class constructor and store it in isolated storage (application can be run form web browser also).

2. At startup retrieve form name and create mdi child from it using reflection.

I'm new to C#. Where to find any sample code for this?

Andrus

C# Asynchronous Sockets

snapplegil15-Apr-07 7:49

snapplegil

15-Apr-07 7:49

Hey,
I am looking for an already written C# class that implements a C# Async Socket.

Can anyone assist?

Thanks in advance!
Snapple.

pbraun15-Apr-07 12:36

pbraun

15-Apr-07 12:36

Look up "Socket Class" in your help. More specifically look at the begin[name] and end[name] methods. The examples given are usually pretty good and give a good idea of how to use them. If you don't feel comfortable with that, then look up the articles on this site with the search text as "Asynchronous Sockets".

If you would like to see a class that implements a client asynchronous connection completely, I do have a complete one.

Phil

Re: C# Asynchronous Sockets

snapplegil15-Apr-07 17:15

snapplegil

15-Apr-07 17:15

If you can, i'd like to see the example you have please.

I know all about the Socket class and I wrote a class that represent an Async Socket, but i'm having some issues with it, so i'd like to try a ready one to see if the problem is in my socket class or program as a whole.

Re: C# Asynchronous Sockets

pbraun15-Apr-07 17:29

pbraun

15-Apr-07 17:29

Please send me an e-mail to which I can send the code directly.

Phil

drag & drop problem

xtremetechnology15-Apr-07 6:23

xtremetechnology

15-Apr-07 6:23

let say i have a panel, and in that panel i loaded an image:
panel.BackgroundImage = Image.FromFile("image.gif");
Now, i what to make drag & drop with this panel and i want to obtain the name of the image. How can i solve this? When i make the drag & drop operation, can i obtain both the image, and the name of the image? how?

Re: drag & drop problem

Luc Pattyn15-Apr-07 8:54

15-Apr-07 8:54

Hi,

the way I understand it is you can create any object you like, and pass it to
Control.DoDragDrop() when you start dragging, and retrieve it from DragEventArgs.Data
when you handle the drop event, so it is possible to store both a file name and a
bitmap, or anything else you choose.

Smile | :)

Luc Pattyn

[My Articles]

Re: drag & drop problem

xtremetechnology15-Apr-07 9:05

xtremetechnology

15-Apr-07 9:05

i succed to drag & drop the backgroundImage of the panel to another panel, but i want to obtain the name of the image too.
I don't know what is the function which get the name of the image.
panel.BackgroundImage = Image.FromFile("pic.gif");
don't exist a function which take an image parameter and return the name and it's path?

Re: drag & drop problem

Luc Pattyn15-Apr-07 9:15