Re: C# custom event handlers/controls - C# Discussion Boards

donovan.solms26-Jun-07 5:14

26-Jun-07 5:14

it's for a multitouch screen, so pressing two fingers on an image does do quite different things than pressing two fingers on something else. so emulating the mouse is not quite a good solution

rather have something you don't need, than need something you don't have

originSH26-Jun-07 5:38

originSH

26-Jun-07 5:38

No I mean don't the touch screen drivers interpret the touching as mouse stuff?

i.e. when you tap the monitor driver does a mouse click on that location

Edit:

Oh wait I reread what you were on about and I think I got confused.

The C++ app handles the touchside of things? It recieves the messages fro mthe touch screen and then tells the C# app.

What you want is then to make controls where the recieved messages fire events.

i.e.

Touch on the screen >> C++ app >> C# app >> fire event on control

donovan.solms26-Jun-07 6:01

26-Jun-07 6:01

Touch on the screen >> C++ app >> C# app >> fire event on control

exactly

rather have something you don't need, than need something you don't have

originSH26-Jun-07 6:24

originSH

26-Jun-07 6:24

ahhhh got ya Smile | :)

Well you'll need to inherit each control in the framework and extend it with the new events you want. It'd probably be best to make an interface like ITouchableControl that defines the set of events you want and then have each new control impliment it.

The final bit is tell the control when it needs to fire the new events. You need some way of testing if the event from the touch screen is applicable to a cirtain control. You can do this using each controls location and seeing if it matches up with the event, if so then the control can fire its own event to notify anyone whos listening.

As to the exact implimentation of the final bit theres a few different routes you could go. You could have a central class that each control registers itself with, that singleton class would then handle all of the figuring out which controls are applicable and then inform each control as to what it needs to do. The other option is to have each control listen to the events and figure out for itself if it needs to fire its relivent events.

donovan.solms26-Jun-07 10:40

26-Jun-07 10:40

thanks. that is what i was looking for! the singleton will solve a lot of problems.

thanks again.

donovan

rather have something you don't need, than need something you don't have

originSH26-Jun-07 22:11

originSH

26-Jun-07 22:11

Here's the code for singletons I personally use in C#:

http://www.codeproject.com/cs/design/GenericSingletonPattern.asp[^]

I've found it does eveything I want it to most of the time.

led mike26-Jun-07 5:39

led mike

26-Jun-07 5:39

donsolms wrote:
so pressing two fingers on an image does do quite different things than pressing two fingers on something else

What the heck does that mean? "pressing two fingers"? What difference does it make how many fingers you use to press with? And why would you use more than one? Doesn't that make it more difficult to hit your target?

And what does "does do quite different things than pressing two fingers on something else" have to do with "how" you capture the "press" event? Confused | :confused:

Are you confused... because I sure am.

donovan.solms26-Jun-07 5:59

26-Jun-07 5:59

ok. let me explain. it's a multitouch screen i built myself. it gets a videofeed from a camera of where you press your finger. the unmanaged c++ app does the tracking of the fingers. then i built a managed wrapper to get the 'events' raised by the unmanaged part. now that is working. now i need to add those touch events to a UIElement in wpf. now doing it with one object is no problem, but doing it with say Image and Button is a whole different story. because once i add a UIElement implemented to receive touches, the app runs but without allowing the other one for touches. so i want to build a framework that allows for more than one element to be touched. the basics should be the same as the normal mousedown event.

as for "doing different things" and "why whould you use more than one finger"?

google/youtube for 'microsoft surface', or 'jeff han ftir' and you'll see why more than one finger and why it does different things when you touch different objects.

@led mike - you're right : "And what does "does do quite different things than pressing two fingers on something else" have to do with "how" you capture the "press" event? " has nothing to do with it, it was just to better explain.

rather have something you don't need, than need something you don't have

led mike26-Jun-07 6:13

led mike

26-Jun-07 6:13

donsolms wrote:
google/youtube for 'microsoft surface', or 'jeff han ftir'

Very nice, thanks. Yeah since this is all bleeding edge stuff I have no clue.

Please correct the error.....

Dave Kreskowiak26-Jun-07 5:37

Dave Kreskowiak

26-Jun-07 5:37

To support multiple touches, you'd probably need an SDK for that tablet. There isn't any built in support in Windows to handle this.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007

help as an alias26-Jun-07 2:16

help as an alias

26-Jun-07 2:16

private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                string str = "provider=Microsoft.Jet.OLEDB.4.0;data source=1.mdb";
                OleDbConnection passconn = new OleDbConnection(str);
                string sql = "select * from password where username='" + this.textBox1.Text + "' and password ='" + this.textBox2.Text + "'";
                passconn.Open();
                OleDbCommand cmd = new OleDbCommand(sql, passconn);
                object result;
                result = cmd.ExecuteScalar();
                int myint = (int)result;
                if (myint == 1)
                {
                    this.Hide();
                    MDIParent mdi = new MDIParent();
                    mdi.Show();

                }
                else
                {
                    MessageBox.Show("Please enter the correct user name password");
                    textBox1.Text = "";
                    textBox2.Text = "";
                    textBox1.Focus();
                }
                passconn.Close();
                cmd.Dispose();
            }
                catch(OleDbException ex)
            {
                    MessageBox.Show(ex.Message);
            }
            }

friends i goot puzzled please help me i m new.

Manas Bhardwaj26-Jun-07 2:19

Manas Bhardwaj

26-Jun-07 2:19

Wats the error? Mad | :mad:

Colin Angus Mackay26-Jun-07 2:21

26-Jun-07 2:21

Sorry, but I'm not going to read that looking for an error unless I know what I'm supposed to be looking for.

What is the error? Where is the error? What should it do instead?

At a quick glance I can tell you that your code is susceptable to a SQL Injection Attack. Read this for tips on how to prevent SQL Injection Attacks.[^]

Upcoming events:
* Glasgow: Mock Objects, SQL Server CLR Integration, Reporting Services, db4o, Dependency Injection with Spring ...
* Reading: Developer Day 5

Ready to Give up - Your help will be much appreciated.

My website

kubben26-Jun-07 2:22

kubben

26-Jun-07 2:22

There are a few issues with this code. Like you are trying to return a scalar but you are doing select * from password. I think there is perhaps one column that you want to return that you are expecting to be an integer. I think perhaps your code might work better if you did select count(*) from password ... Then you should get the number of records returned that match your username and password.

Hope that helps.
Ben

Colin Angus Mackay26-Jun-07 2:23

26-Jun-07 2:23

The fact that the password is being stored in clear text is a big WTF | :WTF:

in itself.

kubben26-Jun-07 2:29

kubben

26-Jun-07 2:29

Yes, and like you mentioned in your post sql injection attacks. Still I figure try to help if I can. It is kind of funny how often people expose themselves to sql injection attacks. I read your posts sometimes and it seem more often then not you add a link to your article about it. I guess you can only hope that sooner or later more people will realize the need to use stored procedures all the time for everything instead of taking the easy way out. Of course, this is an access app so I guess that isn't an option.

Ben

Colin Angus Mackay26-Jun-07 2:30

26-Jun-07 2:30

kubben wrote:
Of course, this is an access app so I guess that isn't an option.

There is still the option of parameterised queries - that does go some way to protecting the database.

Gamzun26-Jun-07 2:35

Gamzun

26-Jun-07 2:35

hehe sounds quite funny! Laugh | :laugh:

your username and password must be wrong and you must be getting this pop up "Please enter the correct user name password" :P

or may be you're playing with us!

help as an alias26-Jun-07 2:46

help as an alias

26-Jun-07 2:46

no friend this shows the error

Colin Angus Mackay26-Jun-07 2:47

26-Jun-07 2:47

What is the error? There is no point saying it shows the error if we don't know what it is. If you want us to help you, you have to help us understand your problem first.

Gamzun26-Jun-07 2:51

Gamzun

26-Jun-07 2:51

so brother why don't you tell us the error! Poke tongue | ;-P

help as an alias26-Jun-07 3:25

help as an alias

26-Jun-07 3:25

i dont know

Colin Angus Mackay26-Jun-07 3:35

26-Jun-07 3:35

I'm totally confused. How do you know you have an error if you don't know what it is?

You post code and say it has an error? How do you not know what the error is? Surely the error manifests itself in some way? What is the manifestation of that error? And what should happen if the error was fixed?

mav.northwind26-Jun-07 8:19

mav.northwind

26-Jun-07 8:19

Could it be that this is a kind of homework or test question?
"Name all the errors/problems in this piece of code"

Just a thought...

Regards,
mav

--
Black holes are the places where God divided by 0...

Colin Angus Mackay26-Jun-07 13:55