C# Discussion Boards - CodeProject

Re: System.Diagnostics.Process, asyncronous reading StandardOutput and StandardError streams

Heath Higgins9-Sep-09 13:10

9-Sep-09 13:10

Hi Jon,

I've been struggling with this one for a while myself and was able to create a scenario where standard out/err data were not handled by dumping a large number of lines from the process right before exiting. I had hoped to be able to switch from asynchronous to synchronous reads once the WaitForExit() returns, and then receive the remaining data with a process.StandardOutput.ReadToEnd(). Unfortunately, this is not possible:

"You cannot mix asynchronous and synchronous read operations on the redirected StandardOutput stream. Once the redirected stream of a Process is opened in either asynchronous or synchronous mode, all further read operations on that stream must be in the same mode. If you cancel an asynchronous read operation on StandardOutput and then need to read from the stream again, you must use BeginOutputReadLine to resume asynchronous read operations. Do not follow CancelOutputRead with a call to the synchronous read methods of StandardOutput such as Read, ReadLine, or ReadToEnd."
http://msdn.microsoft.com/en-us/library/system.diagnostics.process.canceloutputread.aspx[^]

As far as I can tell, this applies to anything you could check (process.StandardOutput.EndOfStream) to see if it were necessary for you to delay cleanup. Unless I'm missing something, which is entirely possible, this seems like a shortcoming of the Process class, because it essentially means that you can't trust the asynchronous interface to provide you with all of your data.

Sadly, this seems to leave us with synchronous IO, perhaps a couple extra threads, and the additional synchronization issues that this approach entails (see here[^] for a deadlock condition to watch out for).

The only other thing that has worked for me so far, and this is sort of hackish, is to sleep the thread that handles the Exited event (or a return from WaitForExit) to give the DataReceived events time to fire a few more times. I ended up with something like this:

RunningProcess.Start();
RunningProcess.BeginOutputReadLine();
RunningProcess.BeginErrorReadLine();

while (!Completed && !ProcManager.ProcedureAborted)
{
Completed = RunningProcess.WaitForExit(ProcManager.TSK_ABORT_CHECK_TIMEOUT_MS);
}

if (ProcManager.ProcedureAborted)
{
Thread.Sleep(200);
}

200ms seemed to be sufficient in the scenario that I was working on. This approach has potential issues: behavior may be system dependent, and you're making assumptions about how much time you need to flush the buffers (i.e., you might lose output on a slower system, but nothing that you aren't already losing). You may need to play around with it to find a balance between perceivable performance issues caused by too much delay, and not processing all of the output. Again, you could try moving completely to synchronous IO, but the above approach has worked fairly well for me so far.

Hope this helps,

Heath

Byte to bit array problem

gwithey3-Sep-09 4:58

gwithey

3-Sep-09 4:58

I am experienceing a problem breaking up three bytes of data into bit arrays and assigning a value to an enumeration as a result, code shown bellow:

if (UpdateLEDAndBeepStatus != null)
                  {
                     BitArray byte0 = new BitArray(commandData.Data[0]);
                     BitArray byte1 = new BitArray(commandData.Data[1]);
                     BitArray byte2 = new BitArray(commandData.Data[2]);

                     enumLEDAndBuzzer[] LEDAndBuzz_enumArray = new enumLEDAndBuzzer[15];

                     

                     // byte 0 bit 0
                     if (byte0[0] == true) //byte0.Count .Get(8-8)
                     {
                        LEDAndBuzz_enumArray[0] = enumLEDAndBuzzer.BUZZER_STATE_ON;
                     }
                     else
                     {
                        LEDAndBuzz_enumArray[0] = enumLEDAndBuzzer.BUZZER_STATE_OFF;
                     }
                     // byte 0 bit 1
                     if (byte0[1] == true) //byte0.Count
                     {
                        LEDAndBuzz_enumArray[1] = enumLEDAndBuzzer.LED1_MCUEnable_ON;
                     }
                     else
                     {
                        LEDAndBuzz_enumArray[1] = enumLEDAndBuzzer.LED1_MCUEnable_OFF;
                     }

When the project gets to this stage the values in the bytes are "255".
Should that not mean all 8 bits will be true?

However my code never enters the true section of my if statement claiming "byte0[0]" is false.

Either that or i am going about checking the bit values wrong, can anyone help?

Thanx George Smile | :)

Re: Byte to bit array problem

Henry Minute3-Sep-09 5:24

Henry Minute

3-Sep-09 5:24

Try:

BitArray byte0 = new BitArray(new byte[] {commandData.Data[0]});

I think that what your original line does is to create a BitArray of size 255, not one of size 8 containing 255.

Henry Minute

Do not read medical books! You could die of a misprint. - Mark Twain
Girl: (staring) "Why do you need an icy cucumber?"
“I want to report a fraud. The government is lying to us all.”

Re: Byte to bit array problem

Luc Pattyn3-Sep-09 5:54

Luc Pattyn

3-Sep-09 5:54

your thinking has been correct. I know so by reading the documentation, something everyone should do from time to time.

Laugh | :laugh:

Luc Pattyn

Badger | [badger,badger,badger,badger...]

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Re: Byte to bit array problem

Henry Minute3-Sep-09 6:03

Henry Minute

3-Sep-09 6:03

Luc Pattyn wrote:
your thinking has been correct

That's nice to know. I shall note this rare occurrence in my diary. Smile | :)

Luc Pattyn wrote:
I know so by reading the documentation, something everyone should do from time to time.

So did I, but without trying, or seeing, all of the OPs code, I can never be sure.

Re: Byte to bit array problem

Luc Pattyn3-Sep-09 6:23

Luc Pattyn

3-Sep-09 6:23

Yeah I often regret the declarations aren't included in the code snippet.

Henry Minute wrote:
That's nice to know

Luc Pattyn

Have a look at my entry for the lean-and-mean competition; please provide comments, feedback, discussion, and don’t forget to vote for it! Thank you.

Re: Byte to bit array problem

gwithey3-Sep-09 20:47

gwithey

3-Sep-09 20:47

Thank you it saved me alot of time trying to work it out.

Did wonder why it said the length was 255 when running that was why.

Why listview cannot received the OnDragDrop event.

Fired.Fish.Gmail3-Sep-09 4:33

Fired.Fish.Gmail

3-Sep-09 4:33

Two listview are placed on the form. Then select one item in listviewA and draw it to lsitviewB , why the listViewB cannot get the OnDragDrop event.

Does any other configure need to set ?

when debuging, how to see all the message in this form?

Re: Why listview cannot received the OnDragDrop event.

Nuri Ismail3-Sep-09 5:28

Nuri Ismail

3-Sep-09 5:28

AllowDrop option in the properties for the listView control must be set to True.

Regards,
Nuri Ismail

Re: Why listview cannot received the OnDragDrop event.

Fired.Fish.Gmail3-Sep-09 14:57

Fired.Fish.Gmail

3-Sep-09 14:57

The AllowDrop value has been setten to true, but the program still cannot get the DragDrop message.

But the DragEnter message can be received.

Re: Why listview cannot received the OnDragDrop event.

Nuri Ismail3-Sep-09 21:59

Nuri Ismail

3-Sep-09 21:59

Fired.Fish.Gmail wrote:
the program still cannot get the DragDrop message.

First you have to check if you correctly set the DragDrop event handler. It's very hard to guess where is the problem without a code fragment. You can compare your code with some examples which demonstrate the Drag and Drop concept.

--> Here[^] is an example that implements exactly the Drag and Drop operations between 2 ListViews.

--> Here[^] in the example part of this documentation you will find a brief explanation of Drag and Drop concept. The provided example is about drag and drop implementation between 2 ListBox controls.

I hope this helps. Smile | :)

Regards
Nuri Ismail

Re: Why listview cannot received the OnDragDrop event.

Fired.Fish.Gmail4-Sep-09 3:48

Fired.Fish.Gmail

4-Sep-09 3:48

Thanks Nuri

I know that can not receive the DragDrop event
because in the DragOver event, the e.Effect was set as Link.
But the AllowEffect is ALL(Copy|Move) so the DragDrop event cannot do.

C# Multilanguage resx

Kaare Tragethon3-Sep-09 4:29

Kaare Tragethon

3-Sep-09 4:29

Dear all.

I'm a total newbie to programming (I have made som very trivial applications in C#). Right now I'm looking at multilangual programming for the Windows User Interface. Could anyone provide a really (and I mean really) simple code/application which shows how to implement multilangual controls?

I have searched both Google and CodeProject, but most of the examples there are a bit too "difficult" for me to understand at this point, and most often the examples contain a lot more than just the language function. I know it has something to do with multiple resx files, but that's about it.

Thanks in advance.

Re: C# Multilanguage resx

stancrm3-Sep-09 5:34

stancrm

3-Sep-09 5:34

The easiest way is :

1. Create Resource.resx in Visual Studio and add some text in it, for example :
MyText : World

2. Then create Resource.de.resx in Visual Studio and add some text in it, for example :
MyText : Welt

In your source code, you can call it using :
MessageBox.Show(Resource.MyText);

The content of Resource.MyText is depend on your CurrentCulture.
If your CurrentCulture is English, then you get "World"
If your CurrentCulture is German, then you get "Welt"

Re: C# Multilanguage resx

Kaare Tragethon3-Sep-09 5:50

Kaare Tragethon

3-Sep-09 5:50

Thank you very much!

Windowmediaplayer control

Yonathan11113-Sep-09 4:21

Yonathan1111

3-Sep-09 4:21

Hi all, especially to stancrm. I inlude the components in my code, but it only plays when the entire program runs. I mean I cannot control the wmp interface, even it doesn't work using button. I think I missed some concepts. pleas help me I want to make my own wmp(sample).

Re: Windowmediaplayer control

Nuri Ismail3-Sep-09 5:09

Nuri Ismail

3-Sep-09 5:09

Here[^] you will find some basic instructions on how to control the WMP. It is a "step by step" explanation of creating an application that plays video and uses custom play and stop buttons. I think that it's a good start point.

If you need something more complex have a look at the Remote control media player[^] article.

Regards,
Nuri Ismail

flexible datagrid

kruegs353-Sep-09 3:10

kruegs35

3-Sep-09 3:10

Is the datagrid control the only grid available in C#? I am more familiar with delphi and stringgrids, which allow me to set certain cells, rows, or columns to read-only, different colors, or sizes, etc... Does the datagrid control have any of this functionality? I have only be able to find tutorials on how to view, add, or delete data. Can anyone offer any advice? thanks.

Re: flexible datagrid

stancrm3-Sep-09 3:21

stancrm

3-Sep-09 3:21

http://msdn.microsoft.com/en-us/library/system.windows.forms.datagridview.aspx[^]

It is good. It enough for normal job. If you want more, you can derive from it and extend it by yourself or buy some third party datagrid.

[Message Deleted]

gamer11273-Sep-09 2:17

gamer1127

3-Sep-09 2:17

[Message Deleted]

Re: Converting int type radix sort to string type radix sort

ghelhei3-Sep-09 3:23

ghelhei

3-Sep-09 3:23

jai eto nkita ko code

public void RadixSort(int[] a)
{
// our helper array
int[] t=new int[a.Length];

// number of bits our group will be long
int r=4; // try to set this also to 2, 8 or 16 to see if it is
//quicker or not

// number of bits of a C# int
int b=32;

// counting and prefix arrays
// (note dimensions 2^r which is the number of all possible values of a
//r-bit number)
int[] count=new int[1<<r];
int[] pref=new int[1<<r];

// number of groups
int groups=(int)Math.Ceiling((double)b/(double)r);

// the mask to identify groups
int mask = (1<<r)-1;

// the algorithm:
for (int c=0, shift=0; c<groups; c++, shift+=r)
{
// reset count array
for (int j=0; j<count.Length; j++)
count[j]=0;

// counting elements of the c-th group
for (int i=0; i<a.Length; i++)
count[(a[i]>>shift)&mask]++;

// calculating prefixes
pref[0]=0;
for (int i=1; i<count.Length; i++)
pref[i]=pref[i-1]+count[i-1];

// from a[] to t[] elements ordered by c-th group
for (int i=0; i<a.Length; i++)
t[pref[(a[i]>>shift)&mask]++]=a[i];

// a[]=t[] and start again until the last group
t.CopyTo(a,0);
}
// a is sorted
}

Inner join on Xml

kKamel3-Sep-09 1:23

kKamel

3-Sep-09 1:23

Hello I have 2 xml one of them has a same data but less in records i want to get their inner join, i searched alot but they always mention merge merging them was not help full at all since they get all combined

What i want:
XML1 XML2 MyXmlShould have
---- ---- ----------------
1 2 2(plus its menu item since xml has menu item & menu sub Item ) here the 2 stands for Menu)
2
3

Re: Inner join on Xml

SeMartens3-Sep-09 1:52

SeMartens

3-Sep-09 1:52