Re: About threading - C# Discussion Boards

Hi!
How can we code to make assure that if the thread we want to abort is processing a function, it just be aborted after finish that function ?
Thanks!

Here is one way of stopping your thread, making sure your current execution ends and you do not get an AbortException. You would have something like this to establish the thread in your main processor:

C#

ThreadClass function = new ThreadClass();  // your process
myThread = new ThreadStart(function.Process);

your Process would be something like this:

C#

public bool ThreadWanted = true;
... init/constructor logic ...
do
{
   if (  ..no data to process.. )
       Thread.Sleep(50);
   ...function
}
while (ThreadWanted)
return;

when you want the thread to abort just do this in the thread creator logic:

C#

public void TerminateProcess()
{
  function.ThreadWanted = false;
}

There are 10 kinds of people in the world.

Those that read binary...

...and those who don't.

Hi!
Thanks a lot! Smile | :)

You need to declare the bool variable with the volatile qualifier, without it, there is no guarantee that setting it to true would immediately reflect in the other thread.

Regards
Senthil
_____________________________
My Blog | My Articles | WinMacro

Well i got problem, i have in form the panel, where i draw shapes, and a treeview where i insert the data about shapes Smile | :)

I want to do it in two different threads, but how to do it? I explaine my architecture:
I got a class TOC derived from treeview, and i got a mapcontrol derived from panel, and i have maptable - array of objects. So, when i add new object in the maptable i update data in two components - mapcontrol and TOC... All the objects linked to each other (by references). If it's possible without having static variables?

Any time you have a process using Forms, you will have issues when dealing with more than one thread. But what you describe sounds like you need to consider implementing the Model, View, Controller pattern to solve your problem.

In the MVC pattern, your various elements on your form are Views of data. The Model handles read/update of data and implements an Observer pattern. The Views are subscribers to the Observer.

The controller creates the Views, tells them their states, and receives events that represent User Gestures. So when a 'user gesture' occurs that changes data in your TOC (for example) the controller notifies the Model what that change is (maybe by something like model.StateChange(chapterChosen)).

The model gets that particular chapter object, and raises the Observer event. The Views receive the event and read the data specific to each view from the Model. Thus you change one control and all of the controls automatically change.

There are 10 kinds of people in the world.

Those that read binary...

...and those who don't.

Yes , this is the way i saw, but...
Your next words:
"The Views receive the event and read the data specific to each view from the Model"
How can views read the data of another class (controller)? Because when i make the thread i can read only static members...
Maybe little example could help me... Maybe i don't understand you...

Many of the Patterns websites discusses MVC...but an example is a Form with two temperature boxes -- one 'view' displays Fahrenheit and the other 'view' displays Celcius.

The controller creates each view:

TempView fView = new TempView(TempState.Fahrenheit);
TempView cView = new TempView(TempState.Celcius);
myForm.FTempPanel.Controls.Add(fView));
myForm.CTempPanel.Controls.Add(cView);

the controller then gets the model:

Model mymodel = new Model();

The controller then passes the IObservable data to each view

fView.SetObserver(mymodel.GetObserver);
cView.SetObserver(mymodel.GetObserver);

Finally controller wants a starting temperature to display. I'd normally get it from a saved control file but for this example it is hard coded {shudder}:

mymodel.SetTemp(75);

Now...when the views got the observer interface, they used that to register:

public void SetObserver(IObservable myObserver)
{
       myObserver.DataChangeEvent += new DataChangeHandler(newTemp);
}

when the model gets called with SetTemp() the model notifies the observers that there is new data:
public void SetTemp(int temperature)
{
mytemp = temperature;
ChangeEventArgs myargs = new ChangeEventArgs("temp");
if (DataChangeEvent != null)
DataChangeEvent(this, myargs);
}

Now -- the model DataChangeEvent is happening inside the message pump thread. As a result your form can deal with the event and change the form without having the message pump get confused. So in your TempView object you have an event handler that just says:

public void newTemp(object sender, ChangeEventArgs args)
 {
      if (args.ChangeType == "temp")
          this.temperature.Text = myObserver.GetTemperature(myState).ToString();
 }

So the view recognized that the change was one that affected itself, it made a call into the model (readonly!!!!) to get the temperature and the model used the state to return the correct value of Fahrenheit or Celcius.

Now if you add a slider to the form (which is your TOC) and that is a view that changes temperature, it's only job is to talk to the controller. If the slider is moved, the end result is passed to the controller as a user gesture:

IN THE CONTROLLER

...  TempSlider slider = new TempSlider();
     slider.SetUserChangesTempEvent(new EventHandler(ChangeTemp);
     myForm.SliderPanel.Controls.Add(slider);

and in the slider...

public class TempSlider
 {
    ...
    public void Slider_ValueChange()
    {
        .. after validating the input to verify it is correct
        TempArgs args = new TempArgs(slider.Value.ToString);
        if (UserHasChangeTempEvent != null)
            UserHasChangeTempEvent(this, args);
    }

finally the controller gets the changed temp event, calls the model with the new value, and the model notifies the observers who change to the new value.

It is more complex but you can quickly see that your views are completely free from the form, placement on the form, and from the data. Events happen within the Apartment Thread and the forms get updated without impact to the forms, the message pump, etc. To have an independant thread run, the changed data is just one more UserGesture inside of your control. I tend to encapsulate the Event registration in a method call in case I want to do anything fancy or have multiple event registrations respond to the same eventhandler.

Hope this helps. Google Model View Controller Pattern to find out more.

For example here is my code:

using System;
using System.Windows.Forms;
using System.Drawing;
namespace GeoObjects
{
	/// <summary>
	/// 
	/// </summary>
	
	
	public class GeoTOC : System.Windows.Forms.TreeView
	{
		private System.ComponentModel.IContainer components;
		private System.Windows.Forms.ImageList imageList_LayersColor;
		GeoMapControl m_pGeoMapControl;
		public GeoTOC()
		{
			// 
			// TODO: Add constructor logic here
			//
			InitializeComponent();
		}

		private void InitializeComponent()
		{
			this.components = new System.ComponentModel.Container();
			this.imageList_LayersColor = new System.Windows.Forms.ImageList(this.components);
			// 
			// imageList_LayersColor
			// 
			this.imageList_LayersColor.ImageSize = new System.Drawing.Size(16, 16);
			this.imageList_LayersColor.TransparentColor = System.Drawing.Color.Transparent;
			// 
			// GeoTOC
			// 
			this.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
			this.CheckBoxes = true;
			this.ImageIndex = 0;
			this.ImageList = this.imageList_LayersColor;
			this.SelectedImageIndex = 0;

		}
#region  Accessors
		public GeoMapControl MapControl
		{
			set
			{
				m_pGeoMapControl = value;
				m_pGeoMapControl.TOC = this;
			}
		}
#endregion
		public void UpdateTable()
		{
			this.BeginUpdate();
			Nodes.Clear();
			imageList_LayersColor.Images.Clear();
			System.Drawing.Bitmap img = new System.Drawing.Bitmap(16,16);
			Graphics g = Graphics.FromImage(img);
			g.Clear(Color.White);
			g.Dispose();
			imageList_LayersColor.Images.Add(img);
			foreach(GeoMapTable gmt in m_pGeoMapControl.MapTables)
			{
				TreeNode Map = Nodes.Add(gmt.Name);
				Map.Checked = gmt.Visible;
				Map.ForeColor = Color.Blue;
				foreach(GeoLayer gl in gmt.Layers)
				{
					img = new System.Drawing.Bitmap(16,16);
					g = Graphics.FromImage(img);
					g.Clear(Color.White);
					g.FillRectangle(new SolidBrush(gl.LayerColor),3,3,11,11);
					g.Dispose();
					imageList_LayersColor.Images.Add(img);
					TreeNode layer = Map.Nodes.Add(gl.Name);
					layer.Checked = gl.Visible;
					layer.ImageIndex = imageList_LayersColor.Images.Count-1;
					layer.SelectedImageIndex = imageList_LayersColor.Images.Count-1;
				}
			}
			this.EndUpdate();
		}
		protected override void OnAfterCheck(TreeViewEventArgs e)
		{
			TreeNode parent = e.Node.Parent;
			if(parent==null)
				((GeoMapTable)m_pGeoMapControl.MapTables[e.Node.Index]).Visible = e.Node.Checked;
			else
				((GeoLayer)((GeoMapTable)m_pGeoMapControl.MapTables[parent.Index]).Layers[e.Node.Index]).Visible = e.Node.Checked;
			m_pGeoMapControl.PaintMap();
			base.OnAfterCheck (e);
		}
	}
}

How can i make the method UpdateTable() in the thread???

I tried next, and got next error message :An unhandled exception of type 'System.InvalidOperationException' occurred in system.windows.forms.dll

Additional information: The action being performed on this control is being called from the wrong thread. You must marshal to the correct thread using Control.Invoke or Control.BeginInvoke to perform this action.:

 using System;
using System.Windows.Forms;
using System.Drawing;
using System.Threading;
namespace GeoObjects
{
	/// <summary>
	/// 
	/// </summary>
	class FillIn
	{
		static GeoObjects.GeoTOC m_pGeoTOC;
		public FillIn(GeoTOC toc)
		{
			m_pGeoTOC = toc;
		}
		public static void Process()
		{
			m_pGeoTOC.UpdateTableThread();
		}
	}
	public class GeoTOC : System.Windows.Forms.TreeView
	{
		private System.ComponentModel.IContainer components;
		private System.Windows.Forms.ImageList imageList_LayersColor;
		GeoMapControl m_pGeoMapControl;
		public GeoTOC()
		{
			// 
			// TODO: Add constructor logic here
			//
			InitializeComponent();
		}

		private void InitializeComponent()
		{
			this.components = new System.ComponentModel.Container();
			this.imageList_LayersColor = new System.Windows.Forms.ImageList(this.components);
			// 
			// imageList_LayersColor
			// 
			this.imageList_LayersColor.ImageSize = new System.Drawing.Size(16, 16);
			this.imageList_LayersColor.TransparentColor = System.Drawing.Color.Transparent;
			// 
			// GeoTOC
			// 
			this.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
			this.CheckBoxes = true;
			this.ImageIndex = 0;
			this.ImageList = this.imageList_LayersColor;
			this.SelectedImageIndex = 0;

		}
#region  Accessors
		public GeoMapControl MapControl
		{
			set
			{
				m_pGeoMapControl = value;
				m_pGeoMapControl.TOC = this;
			}
		}
#endregion
		public void UpdateTableThread()
		{
			this.BeginUpdate();
			Nodes.Clear();
			imageList_LayersColor.Images.Clear();
			System.Drawing.Bitmap img = new System.Drawing.Bitmap(16,16);
			Graphics g = Graphics.FromImage(img);
			g.Clear(Color.White);
			g.Dispose();
			imageList_LayersColor.Images.Add(img);
			foreach(GeoMapTable gmt in m_pGeoMapControl.MapTables)
			{
				TreeNode Map = Nodes.Add(gmt.Name);
				Map.Checked = gmt.Visible;
				Map.ForeColor = Color.Blue;
				foreach(GeoLayer gl in gmt.Layers)
				{
					img = new System.Drawing.Bitmap(16,16);
					g = Graphics.FromImage(img);
					g.Clear(Color.White);
					g.FillRectangle(new SolidBrush(gl.LayerColor),3,3,11,11);
					g.Dispose();
					imageList_LayersColor.Images.Add(img);
					TreeNode layer = Map.Nodes.Add(gl.Name);
					layer.Checked = gl.Visible;
					layer.ImageIndex = imageList_LayersColor.Images.Count-1;
					layer.SelectedImageIndex = imageList_LayersColor.Images.Count-1;
				}
			}
			this.EndUpdate();
		}
		public void UpdateTable()
		{
			FillIn fi = new FillIn(this);
			Thread mythread = new Thread(new ThreadStart(FillIn.Process));
			mythread.Start();
		}
		protected override void OnAfterCheck(TreeViewEventArgs e)
		{
			TreeNode parent = e.Node.Parent;
			if(parent==null)
				((GeoMapTable)m_pGeoMapControl.MapTables[e.Node.Index]).Visible = e.Node.Checked;
			else
				((GeoLayer)((GeoMapTable)m_pGeoMapControl.MapTables[parent.Index]).Layers[e.Node.Index]).Visible = e.Node.Checked;
			m_pGeoMapControl.PaintMap();
			base.OnAfterCheck (e);
		}
	}
	
	
}

Hi guys,

Pls Could someone help/ tell me how to create a gif file in c# .net as i cant find anything on the subbject.

I basically need to be able to create a gif animation from a series of jpg files,

Any help, ie books, websites, articles anything that you might think will help me pls let me know as i am out of ideas.

Thanks

Strip Images From Animated Gif:

http://www.eggheadcafe.com/articles/stripimagefromanimatedgif.asp

...these actions in reverse may work

P.S. Google: 'c# gif'

thanks for that i will have a go at doing it, pls let me know if you think of anything else which might help.

Thanks

Adobe ImageReady

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnaspp/html/colorquant.asp

this one is nice, that explain how to make a palette.

PS: the transparence doesn't work you must patch it.

thanks ive had a look at that already, if there is anything else you guys can give then pls do,

btw i want to do this in c# i dont want to use adobe or anything else.

Is there a way to compile IL code into native x86 ?
I think in some cases is IL code impractical:

1) speed - some time-critical applications need to be executed quickly, without Just-In-Time debugging (like image viewers)

2) security - this is my case: my app using some product key validation algorithm, which is vulnerable to cracker. Even if the code is obfuscated, attacker can see sensitible data (numbers, math operators and parameters in .NET method calls D'Oh! | :doh:

).

I heard about something like "pre-jitter" - a tool from Microsoft for additional compilation of your code.

It's better for me to make six releases of my program, than to have multiplatform and unsafe one.
Maybe the program can be grabbed directly from memory. Confused | :confused:

Have you some experience with IL code security?

IL to native would mean compiling the .NET virtual machine and your app into one big file. The security of a native program is not much better than the security of IL, because somebody who really wants to see what it does can still disassemble it.

What do you think of this idea:
You encrypt the .exe file during installation, and decrypt it on startup.
The only .exe file the user sees in the installation directory is the decrypter, the actual application exists only at runtime.

_________________________________
Please inform me about my English mistakes, as I'm still trying to learn your language!

Well, it's not a bad idea. I looked over a RemoteSoft's Slamander site. They provides something called "protector". It works with code encryption and seems to be enough for code safety:

http://www.remotesoft.com/salamander/protector.html

(there's also some talk about MSIL -> native code)

i want any paper talk about MDI forms and different types of conrtols that i can open it inside MDI form (Ex. DLL, OCX.....) using C#, please anyone know anything about this please answer me

Doesn't exist.

An MDI Parent or Child form is just another form, with all the abilities of a normal form.

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

Do you mean that i can't call DLL or OCX from MDI form

No, you can!! Just like any other form can.

Just the documention you want doesn't exist, because there are no functional differences.

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

thanks for your help
if you have any papers or link talk about how to use DLL and OCX in C#.Net please tell me
thanks again

There are examples all over the place.

For OCX, or ActiveX, controls, add it to the Toolbox or add a Reference to it.

For using .DLL's, checkout DllImport, or look on http://www.pinvoke.net[^].

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