Re: Threading concept.. - C# Discussion Boards

Eduard Keilholz18-Jul-07 22:47

18-Jul-07 22:47

I think an exception IS thrown however you catch it on some place. You cannot change GUI related things on a diffrent thread.

Try creating a delegate and call the delegate from your diffrent thread using Invoke()

for example :

<br />
private delegate void doBindListbox();<br />
private void BindListbox()<br />
{<br />
// Code to bind listbox<br />
}<br />

and call the delegate from your diffrent thread like so :

<br />
this.Invoke(new doBindListbox(BindListbox));<br />

.: I love it when a plan comes together :.
http://www.zonderpunt.nl

Ron.S18-Jul-07 22:58

18-Jul-07 22:58

Hi,

Is this the correct way?
trd = new Thread(new ThreadStart(this.Invoke(new delegateloaddata(loaddata))));

delegateloaddata = delegate.
loaddata = is the method which has to be called through thread

Bharath.S Ron

Eduard Keilholz19-Jul-07 0:57

19-Jul-07 0:57

No, it's not...

<br />
private void StartMyThread()<br />
{<br />
ThreadStart ts = new ThreadStart(InvokeBinding);<br />
Thread th = new Thread(ts);<br />
th.Start();<br />
}<br />
<br />
private void InvokeBinding()<br />
{<br />
this.Invoke(new doBindListbox(BindListbox));<br />
}<br />

See the example in my previous post....

.: I love it when a plan comes together :.
http://www.zonderpunt.nl

Ron.S19-Jul-07 2:41

19-Jul-07 2:41

Thank you.

I tried that method it is working and loading the data into the listbox but, it is not working as a thread. I cannot stop it in between.

Bharath.S Ron

Eduard Keilholz19-Jul-07 3:16

19-Jul-07 3:16

What do you mean with :

Bharath.S.Ron wrote:
I cannot stop it in between.

.: I love it when a plan comes together :.
http://www.zonderpunt.nl

Ron.S19-Jul-07 19:39

19-Jul-07 19:39

Hi,

AS i am trying to impliment that as a thread , i want to stop it in between as well.
stop in the sense, the form should not freeze while performing that function, i should be able to click other buttons as well while this is being doing its job.

Bharath.S Ron

Ron.S19-Jul-07 20:30

Visual studio error on load

19-Jul-07 20:30

this is the code which i am using.

public void loaddata()
{
try
{
conn = new SqlConnection("Data Source=local; Initial Catalog=Northwind; User ID=sa; Password=; Persist Security Info =True;");
adpt = new SqlDataAdapter("Select * from Categories", conn);
ds = new DataSet();
adpt.Fill(ds);
listBox1.DataSource = ds.Tables[0];
//trd
listBox1.DisplayMember = "CategoryName";
Thread.Sleep(1000);
//trd.Start();
}
catch (SqlException ex)
{
MessageBox.Show(ex.Message.ToString());
}
}

on click of the button i am calling that thread.

private void btnStart_Click(object sender, EventArgs e)
{
try
{
// this is wokring

ThreadStart myThreadDelegate = new ThreadStart(loaddata);
trd = new Thread(myThreadDelegate);
trd.Start();
trd.IsBackground = true;
// till here
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
}

}

this below code is to stop the thread.
private void btnStop_Click(object sender, EventArgs e)
{
//Thread trd = new Thread(new ThreadStart(this.loaddata));
//trd.Abort();
try
{
if ((trd.ThreadState == ThreadState.Running )|| (trd.ThreadState==ThreadState.Background))
{
trd.Abort();
}

}
catch (ThreadStateException Ex)
{
MessageBox.Show(Ex.ToString(), "Exception",
MessageBoxButtons.OK, MessageBoxIcon.Error,
MessageBoxDefaultButton.Button1);
}
}

please help me..

Bharath.S Ron

Custom Tab Control

T.EDY18-Jul-07 22:39

T.EDY

18-Jul-07 22:39

Hi,

I Have Some Problem how can we bind data into tab control..for example:

i have a table name Working, in first column i have field name "Id" for primary key and i make it autoincrement, and in the second column i have field name Status..what makes me confuse if on field status have 2 value :"typing, printing"..how can i make tab control have 2 tabPages name "typing" and "printing"

Please Help me coz i'm new in C#...

Thanks and Regard,

TCim

Russell Jones18-Jul-07 22:29

Russell Jones

18-Jul-07 22:29

I'm getting the following error:

Project FooBar could not be opened because the Microsoft Visual C# .NET compiler could not be created.

I reinstalled VS as recommended by the next line of the error message and it all worked fine.

This morning i open VS and guess what, I get the message again. Reinstalling took me hours yesterday and reduced my PC to a uselesss whirring mess for most of that time. It did however fix the problem for the last few hours of the day.

The suggestions i see on the web are that this problem is due to having a pathname over 260 characters in the project but i've moved my project folder to c and it stil doesn't open.

Has anyone else suffered this problem and found a fix?

Thanks

Russell

Re: Visual studio error on load

originSH18-Jul-07 22:50

originSH

18-Jul-07 22:50

I assume you've googled and worked through the results?

http://www.google.co.uk/search?hl=en&q=could+not+be+opened+because+the+Microsoft+Visual+C%23+.NET+compiler+could+not+be+created.&meta=[^]

Re: Visual studio error on load

Russell Jones18-Jul-07 22:57

Russell Jones

18-Jul-07 22:57

yeah,

strangely One of the guys found a solution suggested by ReSharper. I installed Resharper thinking it might tell me what was wrong. When I opened the project my cursor changed to a biohazard symbol with a green arrow and magically my project now works.

Who knows what was up with it, I hope I'm not back here tomorrow having suffered the same problem when i turn my PC on in the morning.

Russell

Re: Visual studio error on load

originSH18-Jul-07 23:56

originSH

18-Jul-07 23:56

wow! it might be worth going over to the resharper forums and asking if they've done a fix for the issue Smile | :)

handle Printer

Chatura Dilan18-Jul-07 22:17

Chatura Dilan

18-Jul-07 22:17

I'm working on a project on controlling the printer using C#. Such as restrict printing, counting no of pages.

I need references...
and I like to share ideas, if you have worked on that kind of project.

Any ideas? any links you know?

Thanks. Smile | :)

Chatura Dilan

Changing color while drag mouse

satsumatable18-Jul-07 22:11

satsumatable

18-Jul-07 22:11

Hi,

I want to change the color of Panel when i drag the mouse, that is color should be changed only where am dragging rest of the area should be as it is.

I have mouse position as like below

temp.X = e.X ;
temp.Y = e.Y ;
mMousePos = this.panel1.PointToScreen (temp);

I want to set the color for the area btw e.X and e.Y

Re: Changing color while drag mouse

Martin#18-Jul-07 22:51

Martin#

18-Jul-07 22:51

Hello,

I think it's best to create an image for your panel and get a Graphics object from that.
With this Graphics object you than can do a lot of fancy stuff.

Here is an example with an panel and MouseMove event:

private Graphics panelGraphics = null;
private Pen panelPen = null;
private Point oldPosition;
private bool init=false;
private void panel2_MouseMove(object sender, System.Windows.Forms.MouseEventArgs e)
{
    if(panel2.BackgroundImage==null)
    {
        panel2.BackgroundImage= new Bitmap(panel2.Width, panel2.Height);
    }
    if(panelGraphics==null)
        panelGraphics = Graphics.FromImage(panel2.BackgroundImage);

    if(panelPen==null)
        panelPen= new Pen(Color.Red,2);

    if(init)
    {
        Point newPostion = new Point(e.X,e.Y);
        panelGraphics.DrawLine(panelPen, oldPosition, newPostion);

        Refresh();
    }
    else
        init=true;

    oldPosition = new Point(e.X,e.Y);
}

Hope it helps!

Note: I instanciated the Graphics and Pen objevt only once, but you have to dispose them in your forms Dispose method.

panelGraphics.Dispose();
panelPen.Dispose();

All the best,

Martin

Character not recognised when reading file

Sean_B18-Jul-07 22:10

Sean_B

18-Jul-07 22:10

Hi,

I'm reading a file using the stream reader into a string, and the character £ which is in the file appears as a sqare box in the string, which I assume means it is unrecognised.
I'd be grateful if someoone can tell me how to get round this.

Sean

Re: Character not recognised when reading file

Guffa18-Jul-07 23:52

Guffa

18-Jul-07 23:52

If the file is not encoded using UTF-8, you have to specify the encoding when creating the stream reader.

---
single minded; short sighted; long gone;

Xml Serialization

jpeg18-Jul-07 21:58

jpeg

18-Jul-07 21:58

Hello, I have one problem in serializing a class using .NET Serialization

for example, I have got something like this :

<br />
class Parking<br />
{<br />
  public List<Vehicle> vehicles<br />
  public Parking() { /*...*/ }<br />
<br />
  /* */<br />
}<br />
<br />
class Vehicle <br />
{<br />
  /* .... */<br />
}<br />
  <br />
class Truck:Vehicle<br />
{<br />
  /* .... */<br />
}<br />
<br />
class Car:Vehicle<br />
{<br />
  /* .... */<br />
}<br />
<br />
class Motorbike:Vehicle<br />
{<br />
  /* .... */<br />
}<br />

I have been trying to serialize a 'Parking' object and the better I got was :

<br />
<parking><br />
    <Vehicles><br />
    <Car> .... </Car><br />
    <Car> .... </Car><br />
    <Truck> .... </Truck><br />
    <Car> .... </Car<br />
    <Truck> .... </Truck><br />
    <Motorbike> .... </Motorbike><br />
    .....<br />
  </Vehicles><br />
</parking>

But my aim is to get this type of XML string (no 'Vehicles' node):

<br />
<parking><br />
  <Car> .... </Car><br />
  <Car> .... </Car><br />
  <Truck> .... </Truck><br />
  <Car> .... </Car<br />
  <Truck> .... </Truck><br />
  <Motorbike> .... </Motorbike><br />
  .....<br />
</parking><br />

Have you got any idea to obtain this result ?
Thank you for your help !

jpeg

Eduard Keilholz18-Jul-07 22:50

18-Jul-07 22:50

You can ignore object from being xml serialized using the XmlIgnore attribute

<br />
[XmlIgnore()]<br />
public List vehicles<br />

.: I love it when a plan comes together :.
http://www.zonderpunt.nl

jpeg18-Jul-07 23:43

jpeg

18-Jul-07 23:43

Thank you Eduard for your answer but my problem is not to exclude the list.

The class Parking only contain a List<Vehicle> called 'Vehicles'.

the problem is that I get :

<parking><br />
  <vehicles><br />
     .... all vehicules (classes Car, Truck, Motorbike ...)<br />
  </vehicles><br />
</parking><br />

I only want the 'vehicles' tags to disappear and 'Car', 'Motorbike' or 'Truck' vehicles to inside the 'parking' tags.

With your solution, I get :
</parking> (the content of the 'Vehicles' list is not serialized)

jpeg

Martin#18-Jul-07 23:49

Martin#

18-Jul-07 23:49

Hello,

I don't think that you could deserialze it correctly once it was modified this way.
And I also don't think there is a way to serialize it the way you want it.

All the best,

Martin

Eduard Keilholz19-Jul-07 0:01

19-Jul-07 0:01

I think there is, you need to customize the serialization process by making your class IXmlSerializable and use the WriteXml() and ReadXml() functions to write your custom XML message, and Read it when the objects is being deserialized.

The WriteXml and ReadXml will be called by you serializer...

.: I love it when a plan comes together :.
http://www.zonderpunt.nl