Re: Checking for a Key Sequence - Windows Forms Discussion Boards

Trollslayer10-Nov-07 5:55

10-Nov-07 5:55

This sounds like it's more about the architecture of the application than the scanner.
If you check for keys received by the application then you can detect the 02x03x sequence there and clear the buffer, move the focus etc.
This could be done using accelerators for example.

Elaine Rose | [Rose]

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Re: Checking for a Key Sequence

Brady Kelly10-Nov-07 6:04

Brady Kelly

10-Nov-07 6:04

You're right, it is about the application, not the scanner. That's why I moved it here. Wink | ;)

I'm a little concerned about the potential size of the buffer before a 02x03x is detected, so when I get home I'm going to look into a either a circular buffer, or a background thread to clear the buffer during states where a scan should not occur.

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Re: Checking for a Key Sequence

Trollslayer10-Nov-07 6:28

Trollslayer

10-Nov-07 6:28

Sorry, I don't see why you need a buffer at all.
Step 1: start sequence received as a pair of accelerators
Step 2: set focus to edit box
Step 3: use EN_MAXLEN event to detect when the bar code has been scanned (no terminator needed)
Step 4: read edit box and get the barcode

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Re: Checking for a Key Sequence

Brady Kelly10-Nov-07 19:48

Brady Kelly

10-Nov-07 19:48

Elaine, I want to be able to define any sequence of characters as my signal for scanner input, where using accelerators would limit my options there. I also want to cater for EAN-8 as well as 13, so the TAB terminator is perfect, as it will raise the Leave event of my barcode edit box when any code, of any length, is read.

My next challenge is a nice to have, which is a global keyboard hook that ignores all key inputs between my scan signal and terminator. You get some really funny effects scanning when other Windows applications have focus. Windows pop in and out etc.

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Re: Checking for a Key Sequence

Luc Pattyn10-Nov-07 14:24

Luc Pattyn

10-Nov-07 14:24

Hi Brady,

if you want to recognize a specific string (SEQ) the only thing you need
is a buffer of length SEQ.Length; since you need the string value for every
character you append, it is not useful to have a StringBuilder.

Hence use a string (say buf, initialized at "") and do:

buf=buf+e.KeyChar;
if (buf.Length>SEQ.Length) buf=buf.SubString(buf.Length-SEQ.Length, SEQ.Length);
if (buf.Equals(SEQ)) ...

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Re: Checking for a Key Sequence

Brady Kelly10-Nov-07 19:53

Brady Kelly

10-Nov-07 19:53

Luc, it's easier to say,

if (buf.EndsWith(SEQ)) ...

I was doing that before, but I worried about the size of buf just using a string. If the user doing data capture without scanning, bu could get pretty big, and unless there is some internalisation magic I don't understand, every key press will create a new string . I use a StringBuilder so that I can remove the first character before appending the last. It seems to have acceptable performance.

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Re: Checking for a Key Sequence

Luc Pattyn11-Nov-07 3:34

Luc Pattyn

11-Nov-07 3:34

Hi Brady,

Brady Kelly wrote:
every key press will create a new string

So does your statement string buff = keyBuffer.ToString();

Brady Kelly wrote:
I worried about the size of buf just using a string

My statement if (buf.Length>SEQ.Length) buf=buf.SubString(buf.Length-SEQ.Length, SEQ.Length);
limits the string length at all times (to 2 chars in case SEQ=x02x03).

If you don't want to do all the buffer stuff, there is one (slightly more complex)
alternative using a state machine, which basically remembers how many characters of SEQ
have been matched so far. So in one implementation it would use an int state;
and basically do:

if (e.KeyChar==SEQ[state]) state++; else state=0;
if (state==SEQ.Length) {
    state=0;
    ... we got a match
}

the above code however is incorrect as soon as SEQ contains repeating characters though;
if you must cope with the general case it becomes much more complex...

Smile | :)

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Re: Checking for a Key Sequence

Brady Kelly11-Nov-07 3:39

Brady Kelly

11-Nov-07 3:39

Ooh, I really didn't read your first reply properly. Blush | :O

Thanks, I'll look into the state machine a bit later in the project, when I create a base form for all forms that use a scanner.

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Mater / Detail Datagridview

Mr. Candyman7-Nov-07 8:41

Mr. Candyman

7-Nov-07 8:41

Anyone can point me to some Windows Form Free DataGrid-like control that can support Master / Detail View (a hirarchical sub-rows view, that is), if there is any? I've been searching google but couldn't find anything free :P.
Thanks.

Re: Mater / Detail Datagridview

led mike7-Nov-07 8:46

led mike

7-Nov-07 8:46

Mr. Candyman wrote:
I've been searching google

Interesting[^]

Re: Mater / Detail Datagridview

Mr. Candyman7-Nov-07 9:40

Mr. Candyman

7-Nov-07 9:40

Thank you, but I was looking for a control to use in a Windows Application, and all I can see is for web app.

Re: Mater / Detail Datagridview

led mike7-Nov-07 10:41

led mike

7-Nov-07 10:41

Mr. Candyman wrote:
but I was looking for a control to use in a Windows Application

Interesting[^]

Re: Mater / Detail Datagridview

Mr. Candyman7-Nov-07 11:28

Mr. Candyman

7-Nov-07 11:28

Thanks, but again I could'nt find anything useful. What I really need (if possible) is a control like the asp.net details-view (one single datagridview) but for a windows form and free. Some examples where interesting but mostly used 2 datagridviews, and I can do that myself Wink | ;)

expanding label control

abdelhameed817-Nov-07 0:37

abdelhameed81

7-Nov-07 0:37

i am creating a customized messageBox to add the images and the icons that i need. I have a little problem is that the message and the lable that will hold it.

I need to make the lable to expand vertically as much as the text is, but not horizontally, how?

thanks for your help

abdelhameed81

Re: expanding label control

Christian Graus7-Nov-07 9:43

Christian Graus

7-Nov-07 9:43

If you set the height of the control, I'd imagine it wouldn't get any higher.

Christian Graus - Microsoft MVP - C++

"also I don't think "TranslateOneToTwoBillion OneHundredAndFortySevenMillion FourHundredAndEightyThreeThousand SixHundredAndFortySeven()" is a very good choice for a function name" - SpacixOne ( offering help to someone who really needed it ) ( spaces added for the benefit of people running at < 1280x1024 )

DataGridView and Generics

Ponzano Paolo5-Nov-07 23:44

Ponzano Paolo

5-Nov-07 23:44

Hello to everybody,
I've got a problem with datagridview and generics, here's the piece of code :

<br />
  dataGridView1.ReadOnly = false;<br />
      List<Product> myProds = new List<Product>();<br />
<br />
      myProds.Add(new Product("Prod 1", 1, 1));<br />
      myProds.Add(new Product("Prod 2", 2, 2));<br />
      myProds.Add(new Product("Prod 3", 3, 3));<br />
    <br />
      dataGridView1.DataSource = myProds;<br />
      <br />
      myProds.Add(new Product("Prod 99", 99, 99));<br />

on video I've 3 rows but in the datagrid.datasource I've 4 items.
Where do I do wrong?

Thanks in advance

Paolo Ponzano

Re: DataGridView and Generics

Christian Graus5-Nov-07 23:53

Christian Graus

5-Nov-07 23:53

As this is windows forms, there's no databind command, the grid is bound at the point that you set the data source. So, the objects you add after, are there, but the grid does not rebind every time you add an item.

Re: DataGridView and Generics

Ponzano Paolo6-Nov-07 0:29

Ponzano Paolo

6-Nov-07 0:29

so what should I do?
Thanks

Paolo

Re: DataGridView and Generics

Pete O'Hanlon6-Nov-07 1:11

Pete O'Hanlon

6-Nov-07 1:11

Reset the datasource after you have added the new items.

Deja View - the feeling that you've seen this post before.

Re: DataGridView and Generics

Ponzano Paolo6-Nov-07 1:13

Ponzano Paolo

6-Nov-07 1:13

First of all, thanks to all of you for your answe, I've resolved it using BindingList<t> instead of List<t>, now I've a problem of cross-threading but I'm gonna take care of it!

Thanks again

Paolo

Re: DataGridView and Generics

Ponzano Paolo6-Nov-07 1:34

Ponzano Paolo

6-Nov-07 1:34

ok, now that the problem has been fixed we've another one that came out, and for this I need your help at all!!!

This is the main form event :

  private void Form1_Load(object sender, EventArgs e)<br />
    {<br />
      myWorker = new Worker();<br />
      dataGridView1.ReadOnly = false;<br />
<br />
      dataGridView1.DataSource = myWorker.myList;<br />
<br />
      Thread myThread = new Thread(new ThreadStart(myWorker.DoWork));<br />
<br />
      myThread.Start();<br />
    }

The Worker class is this one :

  public class Worker<br />
  {<br />
    public BindingList<Product> myList = new BindingList<Product>();<br />
<br />
    public void DoWork()<br />
    {<br />
      Random r = new Random();<br />
      for(int i=0; i<1000; i++)<br />
      {<br />
        myList.Add(new Product("Test",r.Next(),r.Next()));<br />
        Thread.Sleep(1000);<br />
      }<br />
    }<br />
  }<br />

At the myList.Add(...) I get an exception of type "Cross-thread operation not valid: Control '' accessed from a thread other than the thread it was created on."

But this happen in a Business Object not in a Window's Control. I suppose this's because of the datagridview.Datasource property set, but how can I fix it?

Thanks in advance,
Bests

C# Soap and HTTP

AssemblySoft5-Nov-07 6:16

AssemblySoft

5-Nov-07 6:16

am writing an app that uses the .Net classes TCPClient and NetworkStream to read and write data between 2 machines. All works fine.

I have recently found a need to be able to send Http 1.1 with a SOAP message as the Http body. Currently i am using an XmlDocument to load and parse the SOAP data. However to do this i first have to read in the HTTP header, search for the beginning of the body and construct my own XmlDocument.

There must be a better way. I don't want to call a web service, i just want to send http with a soap body and receive the same.

I am looking for a means of loading in the NetworkStream into some kind of HTTP object to read the http stuff and also load the body into some simple Soap object that can be used to pull out/ set values.

Comments, Suggestions Welcomed.

Carl

cross-post

Luc Pattyn5-Nov-07 6:40

Luc Pattyn

5-Nov-07 6:40