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I'm having a little problem with receiving messages from a thread of mine.
let's say i have this thread method :
private void DoSomething()
{
for (i=0;i<10000;i++)
{
sleep(100);
}
}
How could i send this message back to the calling thread ? Don't misunderstand me : i know all about postmessage, I just don't want to use it. There must be something in the framework to achieve the same goal in a .net fashion.
Thanks for any ideas.
Sacha
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The thread can call a delegate:
<br />
public delegate void Message(string parameter); <br />
public event Message SendMessage; <br />
...<br />
this.Message += new Message( thread_SendMessage );<br />
<br />
private void thread_SendMessage( string parameter ){<br />
Console.WriteLine(parameter);<br />
}<br />
<br />
...<br />
<br />
private void DoSomething(){<br />
for (i=0;i<10000;i++) {<br />
if(Message != null){ SendMessage("hello"); }<br />
sleep(100);<br />
}<br />
}<br />
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Thanks for your answer Corinna,
But i'm afraid this doesn't quite answer my question. using this delegate, the call will be synchronous (at least i think so). Besides, it will be executed on the DoSomething thread instead of being executed on the "calling thread". So, if i have several DoSomething threads active, i would need to lock the content of your thread_SendMessage method, which is precisely what i want to avoid.
Thanks though.
Sacha
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That where Control.Invoke comes in, if you're calling this on a Control (or anything that implements ISynchroniseInvoke). This invokes the delegate in the thread in which the Control was created. Read more about it in the .NET Framework SDK.
Microsoft MVP, Visual C#
My Articles
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So, if i understand well, the target object for my call needs to implement the ISynchronizeInvoke interface (I'm not working with controls), then my thread method would look like this :
private void DoSomething()
{
for (i=0;i<10000;i++)
{
EventTargetObject.BeginInvoke(new MyEventDelegate(EventTargetObject.OnEvent), null)
sleep(100);
}
}
public EventTargetClass
{
private void OnEvent()
{
//do stuff on EventTargetObject without taking care of locking
}
}
does this sound right ?
Looks like we're approaching the solution! Thanks for your answer 
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i found an example on how to implement ISynchronizeInvoke.
http://www.componentware.net/idesign/DesktopDefault.aspx?tabindex=5&tabid=8
That's the only example i could find using google.
Thanks for pointing this interface out.
Sacha
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Given something like the two classes below, I would like to be able to catch (in SimpleClassList) whenever the Position property is set from the SimpleClassList indexer, i.e. myList[3].Position = 1.0.
My first thought was to try something like below in SimpleClassList, (which obviously doesn't work):
public double this[int index].Position {
set {
list[index].Position = value;
Stuff_I_Need_To_Do_If_Position_Is_Changed();
} // set
} // [].Position
How can I do this?
--------------------
public class SimpleClass : IComparable {
double position;
public double Position {
... get and set
} // Position
... more stuff here
} // class SimpleClass
public class SimpleClassList {
private ArrayList list;
public SimpleClass this[int index] {
get {
return (SimpleClass) list[index];
} // get
set {
list[index] = value;
} // set
} // indexer
... more stuff here
} // class SimpleClassList
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The easiest way is to define an event on SimpleClassList and fire that in the set indexer:
public class SimpleClassList
{
private ArrayList list;
public event ItemChangedEventHandler ItemChanged;
protected virtual void OnItemChanged(ItemChangedEventArgs e)
{
if (ItemChanged != null)
ItemChanged(this, e);
}
public SimpleClass this[int index]
{
get { return list[index] as SimpleClass; }
set
{
list[index] = value;
OnItemChanged(new ItemChangedEventArgs(index));
}
}
}
public class ItemChangedEventArgs : EventArgs
{
public ItemChangedEventArgs(int index)
{
this.index = index;
}
private int index;
public int Index
{
get { return index; }
}
}
public delegate void ItemChangedEventHandler(object sender,
ItemChangedEventArgs e);Then just have some class handle the SimpleClassList.ItemChanged event:
simpleClassList1.ItemChanged +=
new ItemChangedEventHandler(OnItemChanged);
private void OnItemChanged(object source, ItemChangedEventArgs e)
{
SimpleClassList list = source as SimpleClassList;
if (list != null)
{
Console.WriteLine(list[e.Index].Position);
}
}There is already an ItemChangedEventHandler and ItemChangedEventArgs defined in System.Windows.Forms, but the constructor is internal (private to other assemblies) so you can't really use it, which is why I define a similar one here.
Microsoft MVP, Visual C#
My Articles
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if your interested contact dan@xeonxstudios.com
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Dragging a file from explorer to my application is fairly easy, but I have a problem figuring out how to drag a file from my app to explorer, so explorer copy the file, from the filename i give it, and to the place where i drop the file...
Any hints?
- Anders
Money talks, but all mine ever says is "Goodbye!"
ShotKeeper, my Photo Album / Organizer Application
[^]
My Photos[^]
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Use the DataFormats.FileDrop with a filename or array of filenames:
DataObject do = new DataObject(DataFormats.FileDrop, filename);
this.DoDragDrop(do, DragDropEffects.Copy); This file has to exist. If you want to stream the file to Explorer, there is a lot of work involved because you must implement IStream or IStorage, define the STGMEDIUM and FORMATETC structs, and P/Invoke the DoDragDrop API from the Structure Storage APIs.
I have had a long, drawn-out (overly drawn-out) conversation about this in this forum with someone not familiar with structure storage, which is a must to understand this properly. If you want to find that threat, I'd say search the comments for either of the structs I mentioned above, since those don't get mentioned much. That should help you find those threads.
Microsoft MVP, Visual C#
My Articles
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Thanks,
It was this line:
DataObject do = new DataObject(DataFormats.FileDrop, filename);
I needed 
I dont need to stream the files to explorer, only to tell explorer to copy the files.
BTW, when working with stuff like structure storage and the like, it's easier when comming from a C(++) background so I'm not afraid of that, I just don't need it
- Anders
Money talks, but all mine ever says is "Goodbye!"
ShotKeeper, my Photo Album / Organizer Application
[^]
My Photos[^]
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Hi,
I'm trying to find a way of associating a form with a window.
ie. when a user opens a particular window or document, an associated
form will popup displaying detail in regard to this document/window.
At the moment, I'm looking at the processes running on a machine to
determine the currently opened apps/windows and running through a
collection of objects to determine if any of these objects are related
to the app or window (from file name)
ie.
I check the processes periodically using a timer
foreach (Process process in Process.GetProcesses()) {
if (onlyApplications) {
if (process.MainWindowHandle != IntPtr.Zero)
get the associated file
feed this into a collection
blah blah blah
if the list changes through a timer tick, refresh the collection.
It seems that this is only way I can determine and keep a relatively accurate list of the currently running processes.
My question is basically, is there an event that fires when a new process
starts up or the content of the currently running processes change.
or
Is there a better way of doing this?
Thanks very much
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No. You pretty much hit the nail on the head...
RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome
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When serializing a class, i'm getting the following invalid xml header
<?xml version=\"1.0\" encoding=\"utf-8\"?>
the contents is formated perfectly, however the header and namespaces become cluttered with back-slashes preceeding all double-quotes.
Where are these backslahes coming from and how can i get rid of them???
The code i used for the serialization is as follows;
private string SerialiseXml( DocumentSearchResponse docSearchResponse )
{
// Declare the XML Serializer.
XmlSerializer oSerializer = new XmlSerializer( typeof( DocumentSearchResponse ) );
MemoryStream ms = new MemoryStream();
XmlTextWriter tw = new XmlTextWriter( ms, new System.Text.UTF8Encoding() );
// Serialize the proxy class into the writer.
oSerializer.Serialize(tw, docSearchResponse);
string s = System.Text.Encoding.UTF8.GetString( ms.GetBuffer() );
// Close the writer.
tw.Close();
ms.Close();
return s;
}
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Is this in the file itself or when you read the string into the s variable and examine it in the debugger? The debugger will escape quotes when using the Autos, Locals, and This debugger windows.
Microsoft MVP, Visual C#
My Articles
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At the point that the class object is serialized into say a TextWriter, if you examine the string then it is littered with escape chars. Which obviously gets carried through when i set a string to the output of the textwriter. What i was trying to do was create a web method which returns a string, which is the xml document.
I've actually solved the problem now, firstly by using a memory stream (so i can set the encoding) i got rid of the /r/n escape characters within the document body. Secondly by setting the quotechar to a single quote i got rid of the escape chars preceeding each ocurance of a quote (as they became single quotes) in the xml header and namespace declaration.
Am i missing something pretty fundemental here or is the practice of returning an xml document as a string not the done thing!! Serializing directly to a file (as in every example on the web) works fine, but in my particular requirement this is pretty useless.
You say the debugger escapes quotes in the Autos, Locals, this windows. does this apply to outputing the string to the immediate window too, as the escape chars where still there.
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Yes, it does apply to the output window as well. A simple test would be to use a StringWriter as the param to an XmlTextWriter, then you already have your string. Output it to a text file and you won't see those escapes. It's just the debugger doing it to you.
Microsoft MVP, Visual C#
My Articles
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Hi,
In an inherited class is it possible to stop the base class constructor from being called?
Thanks
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No. But u can play some tricks and call different base class constructors. That mite work for your case.
top secret xacc-ide 0.0.1
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IIRC, the base constructor must be called in order to initialise things like private member variables that cannot be initialised from a derived class because it will be invisible to the derived class. Probably your best solution would be to create a protected constructor in the base that does nothing and have your derived class call it instead of the default constructor.
"You can have everything in life you want if you will just help enough other people get what they want." --Zig Ziglar
The Second EuroCPian Event will be in Brussels on the 4th of September
Can't manage to P/Invoke that Win32 API in .NET? Why not do interop the wiki way!
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Don't define a default constructor in your inheritted class. Also make the default constructor private in the base class.
Microsoft MVP, Visual C#
My Articles
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Tried that with the base classes constructor being private but then I can't inherit from it ( compile error ).
eg.
public class inheritance
{
public String strName;
private inheritance()
{
showMessage();
}
public virtual void showMessage()
{
MessageBox.Show("Base Class");
}
}
public class inheritance2: inheritance
{
public String strTest;
public override void showMessage()
{
MessageBox.Show("inheritance2");
}
}
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You can inherit, but only if you don't have a default constructor in your derivative class. If the base class's default ctor isn't private, it will be called. See my reply to Alvaro below for an example.
Microsoft MVP, Visual C#
My Articles
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Heath Stewart wrote:
Also make the default constructor private in the base class.
No, the default constructor would always be called, regardless.
Heath Stewart wrote:
Also make the default constructor private in the base class.
If it's private in the base class, the derived class will not be able to call it automatically and the compiler will complain.
The only solution is to add a protected constructor to the base class (assuming you can) and have the derived constructor call that explicitly.
Regards,
Alvaro
Give a man a fish, he owes you one fish. Teach a man to fish, you give up your monopoly on fisheries.
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