|
What's the right way to do this:
var temp = (from pr in context.tblProducts
join pp in context.mmlProductsParts on pr.ProductId equals pp.ProductId
join pa in context.tblParts on pp.PartId equals pa.PartId
where pr.ProductSeries.Contains(searchModel.SearchTerm) ||
pr.ProductNumber.Contains(searchModel.SearchTerm)
select new ProductModel
{
ProductId = pr.ProductId,
ProductNumber = pr.ProductNumber,
ProductSeries = pr.ProductSeries,
Parts = (new PartModel
{
PartId = pa.PartId,
Category = GetCategory(pa.CategoryId),
PartNumber = pa.PartNumber,
Keywords = pa.Keyword,
PartDescription = pa.Description,
Price = pa.Price.Value,
Ratio = pa.Ratio.Value,
Tribal = pa.Tribal
}).ToList())
}).ToList();
The property Parts on the Product model is of type List<partmodel>. The compiler is complaining telling me that PartModel does not contain a definition fo "ToList".
What's the right way to do this??
Everything makes sense in someone's mind
|
|
|
|
|
While I can't understand the depths of this code, I think I can ask an obvious question:
If 'Parts is a list, I assume a generic list of 'PartModel, then why, when you create a new 'PartModel, and assign values to its inner fields, are you not adding it to the 'Parts list ?
"I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone." Bjarne Stroustrop circa 1990
|
|
|
|
|
Hi - I just converted an ASP.Net web app from 2.0 to 4.0 and the XslTransform code that I inherited no longer works in 4.0. I'm told I need to change the code to use XslCompiledTransform. Fine - but I can't figure out how to get XslCompiledTransform to do exactly what I need it to do. I have an XSL file in my project. I do not have an XML or HTML file. The old code read as follows:
using (DataSet data = DataGateway.getAbsence(TripNum))
{
data.DataSetName = "Absence";
data.Tables[0].TableName = "Employee";
XmlDataDocument xmldoc = new XmlDataDocument(Data);
XslTransform xslt = new XslTransform;
string xsltfile = "myfile.xsl";
xslt.Load(xsltfile);
TextWriter writer = new StringWriter();
xslt.Transform(xmldoc, null, writer, null);
MailMessage mail = new MailMessage();
mail.Body = writer.ToString();
mail.From = "me";
mail.To = "you";
}
I've tried to rewrite this by substituting and XsltCompiledTransform object for the XslTransform object, and an XmlWriter object for the TextWriter object, but the xslt.Transform line complains about my using an XmlDataDocument as input. It suggests an XmlReader instead, but I don't know how to pass the data from my DataSet into an XmlReader. Or perhaps XslCompiledTransform is not the way to go Does anyone know?
Thanks!
|
|
|
|
|
|
Do you by any chance have one or more firewalls blockting UDP port 3333?
|
|
|
|
|
Firewalls off. 
Alberto Bar-Noy
---------------
“The city’s central computer told you? R2D2, you know better than to trust a strange computer!”
(C3PO)
|
|
|
|
|
Alberto Bar-Noy wrote: why I am not getting the data
Please describe the expected and actual behavior properly. Is your program hanging? throwing an exception? returning an empty string? or what?
|
|
|
|
|
It just blocks on the receive for ever while the other side transmits data on a loop for ever (with a 30 second sleep in between)
Alberto Bar-Noy
---------------
“The city’s central computer told you? R2D2, you know better than to trust a strange computer!”
(C3PO)
|
|
|
|
|
Hmm. Looks ok to me. Can you see what port the return messages are being sent to on WireShark?
Regards,
Rob Philpott.
|
|
|
|
|
Given I use IPAddress.Any and 0 in the endpoint does it matter?
Alberto Bar-Noy
---------------
“The city’s central computer told you? R2D2, you know better than to trust a strange computer!”
(C3PO)
|
|
|
|
|
They get set on the way out so I don't think that actually has any effect.
My only hunch is that the return message isn't coming back on port 3333. Here's an alternative bit of code I used to to DNS queries using UDP. You could try this instead:
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReceiveTimeout, 1000);
socket.SendTo(requestMessage, requestMessage.Length, SocketFlags.None, server);
byte[] responseMessage = new byte[512];
socket.Receive(responseMessage);
Regards,
Rob Philpott.
|
|
|
|
|
Have you tried googling udpclient receive not working? It offers a number of hints...
|
|
|
|
|
Oh yes before I cme to the board. This was the first thing to do. Tried the hints, the codes the whatnots
Alberto Bar-Noy
---------------
“The city’s central computer told you? R2D2, you know better than to trust a strange computer!”
(C3PO)
|
|
|
|
|
|
Hi All,
I have a winform application connected with a sql server 2005/2008 database. Now i have about 200 stored procedures which i would like to distribute with the application and execute as soon as the user creates a new datbase.
i do not want to make use of the specific dll like sqldmo and sqlserver.management, etc.. I want it to have it as clean as possible.
Below the function i use for testing ( forget the fixed file path ). Creating datbase and tables are no problem. However creation of the storedprocedure returns errors.
************** Exception Text **************
System.Data.SqlClient.SqlException (0x80131904): Incorrect syntax near the keyword 'TO'.
Incorrect syntax near the keyword 'TO'.
Incorrect syntax near '0'.
at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning()
at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj)
at System.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean async)
at System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)
at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
at AgentBase.Business.clsDataModel.fncCreateNewDatabase(String DBNAME, String FILELOCATION) in C:\AgentBase.2010\AgentBase.Business\clsDataModel.cs:line 91
at AgentBase.Gui.usxConnections.butCreateDB_Click(Object sender, EventArgs e) in C:\AgentBase.2010\AgentBase.Gui\usxConnections.cs:line 293
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
Any suggestions, tips, tricks.
using System;
using System.IO;
using System.Data.SqlClient;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using AgentBase.Datalayer;
public static void fncCreateNewDatabase(string DBNAME, string FILELOCATION )
{
SqlConnection myConn = new SqlConnection(Globals.ConnectionString);
string str = "CREATE DATABASE " + DBNAME + " ON PRIMARY " +
"(NAME = " + DBNAME + "_Data, " +
"FILENAME = '" + FILELOCATION + "\\DATA\\" + DBNAME + "_Data.mdf', " +
"SIZE = 10MB, MAXSIZE = 10000MB, FILEGROWTH = 10%) " +
"LOG ON (NAME = " + DBNAME + "_Log, " +
"FILENAME = '" + FILELOCATION + "\\DATA\\" + DBNAME + "_Log.ldf', " +
"SIZE = 5MB, " +
"MAXSIZE = 50000MB, " +
"FILEGROWTH = 10%)";
string myServer = myConn.DataSource.ToString();
SqlCommand myCommand = new SqlCommand(str, myConn);
myConn.Open();
myCommand.ExecuteNonQuery();
myConn.Close();
myConn = new SqlConnection("Server=" + myServer + ";Integrated security=SSPI;database=" + DBNAME + "");
myConn.Open();
SqlCommand cmd = new SqlCommand();
string sourceDir = "C:\\AgentBase.2010\\AgentBase\\bin\\Debug\\database\\";
string[] fileEntries = Directory.GetFiles(sourceDir);
foreach (string fileName in fileEntries)
{
FileInfo file = new FileInfo(fileName.ToString());
string script = file.OpenText().ReadToEnd();
cmd.CommandText = script;
cmd.Connection = myConn;
cmd.ExecuteNonQuery();
}
"
IF exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[sptblPersonGetAll]') and OBJECTPROPERTY(id, N'IsProcedure') = 1)
BEGIN
PRINT 'Dropping procedure sptblPersonGetAll ...'
DROP PROCEDURE [dbo].[sptblPersonGetAll]
END
GO
PRINT 'Creating procedure sptblPersonGetAll ...'
GO
CREATE PROCEDURE [dbo].[sptblPersonGetAll]
(@PE_ID int
,@PE_RE_ID bigint
,@PE_TYPE bigint
,@PE_LASTNAME nvarchar(50)
,@PE_FIRSTNAME nvarchar(50)
,@PE_INITIALS nvarchar(50)
,@PE_CONFIRMATIONS bit
,@PE_INVOICES bit
,@PE_NEWORDER bit
)
AS
SET NOCOUNT ON
SET XACT_ABORT OFF
DECLARE @ProcName varchar(30)
DECLARE @Error integer
DECLARE @RowCnt integer
DECLARE @ErrMsg nvarchar(1000)
DECLARE @Parameters nvarchar(4000)
SELECT @ProcName = object_name(@@procid)
, @Error = 0
, @RowCnt = 0
SET @Parameters = ''
+ ' PE_ID:' + COALESCE(CONVERT(VARCHAR, @PE_ID), 'NULL')
+ ' PE_RE_ID:' + COALESCE(CONVERT(VARCHAR, @PE_RE_ID), 'NULL')
+ ' PE_TYPE:' + COALESCE(CONVERT(VARCHAR, @PE_TYPE), 'NULL')
+ ' PE_LASTNAME:' + COALESCE(CONVERT(VARCHAR, @PE_LASTNAME), 'NULL')
+ ' PE_FIRSTNAME:' + COALESCE(CONVERT(VARCHAR, @PE_FIRSTNAME), 'NULL')
+ ' PE_INITIALS:' + COALESCE(CONVERT(VARCHAR, @PE_INITIALS), 'NULL')
+ ' PE_CONFIRMATIONS:' + COALESCE(CONVERT(VARCHAR, @PE_CONFIRMATIONS), 'NULL')
+ ' PE_INVOICES:' + COALESCE(CONVERT(VARCHAR, @PE_INVOICES), 'NULL')
+ ' PE_NEWORDER:' + COALESCE(CONVERT(VARCHAR, @PE_NEWORDER), 'NULL')
SELECT [PE_ID]
,[PE_RE_ID]
,[PE_TYPE]
,[PE_LASTNAME]
,[PE_FIRSTNAME]
,[PE_INITIALS]
,[PE_SEX]
,[PE_FUNCTION]
,[PE_PHONE]
,[PE_FAX]
,[PE_MOBILE]
,[PE_WEBSITE]
,[PE_EMAIL]
,[PE_SKYPE]
,[PE_LINKEDIN]
,[PE_FACEBOOK]
,[PE_BIRTHDAY]
,[PE_MEMO]
,[IS_DATECREATED]
,[IS_WHO]
,[IS_DATECHANGED]
,[PE_CONFIRMATIONS]
,[PE_INVOICES]
,[PE_NEWORDER]
,[PE_CONTACTFOR]
,[PE_SPEAKSLANGUAGE]
FROM [dbo].[tblPerson]
WHERE (([PE_ID] = @PE_ID) OR (@PE_ID IS NULL))
AND (([PE_RE_ID] = @PE_RE_ID) OR (@PE_RE_ID IS NULL))
AND (([PE_TYPE] = @PE_TYPE) OR (@PE_TYPE IS NULL))
AND (([PE_LASTNAME] LIKE @PE_LASTNAME + '%') OR (@PE_LASTNAME IS NULL))
AND (([PE_FIRSTNAME] = @PE_FIRSTNAME) OR (@PE_FIRSTNAME IS NULL))
AND (([PE_INITIALS] = @PE_INITIALS) OR (@PE_INITIALS IS NULL))
AND (([PE_CONFIRMATIONS] = @PE_CONFIRMATIONS) OR (@PE_CONFIRMATIONS IS NULL))
AND (([PE_INVOICES] = @PE_INVOICES) OR (@PE_INVOICES IS NULL))
AND (([PE_NEWORDER] = @PE_NEWORDER) OR (@PE_NEWORDER IS NULL))
SELECT @Error = @@Error
, @RowCnt = @@RowCount
IF (@Error != 0)
BEGIN
SELECT @ErrMsg = 'Error getting records. Parameters' + @Parameters
GOTO ENDERROR
END
GOTO ENDOK
ENDERROR:
BEGIN
EXEC spErrorLogInsert 'DB Layer', @ProcName, @Error, @ErrMsg
RAISERROR 25000 @ErrMsg
RETURN 1
END
ENDOK:
RETURN 0
GO
IF ( object_id('dbo.sptblPersonGetAll') IS NOT NULL )
BEGIN
PRINT 'Success: Created procedure sptblPersonGetAll.'
END
IF ( object_id('dbo.sptblPersonGetAll') IS NULL )
BEGIN
PRINT 'ERROR: sptblPersonGetAll was not created successfully.'
END
GO
Kind regards,
Marcel Vreuls
AgentBase
<<A good idea can change your life>>
|
|
|
|
|
|
Hi All,
I have an image on which I'm drawing elements ("masks") using a Graphics object (g.DrawCurve, g.FillRectangle, g.DrawPolygon etc.).
Now, when hovering with the mouse over the image, I need to know whether I'm hovering over a mask (a part that was drawn using the Graphics object).
I couldn't find a way to get a Graphic's drawing pixels... any ideas?
Thanks!
|
|
|
|
|
One thing you could do is this:
- have a bitmap ("bm") the same size as the object you are drawing on, then get its graphics ("gbm") and fill with a white backcolor;
- mimic all your drawing on gbm too, using any color but white;
- when you need to know whether a point (x,y) is mask or not, look at bm.GetPixel(x,y) and the color will tell you.
|
|
|
|
|
Hi Guys,
Just a quick question I have c# code working for communicating with a Serial device using the SerialPort Class (see code below):
private void SendEnq(bool blnIncStep)
{
if (blnIncStep)
{
iStep++;
}
byte[] c = new byte[]
{
0x05,
};
spBPDione.Write(c, 0, c.Length);
Console.WriteLine("OUT: " + ByteToHex(c));
}
private void DataRecvEvent()
{
int bytes = spBPDione.BytesToRead;
byte[] comBuffer = new byte[bytes];
spBPDione.Read(comBuffer, 0, bytes);
Console.WriteLine("IN: " + ByteToHex(comBuffer));
Console.WriteLine("STEP:" + iStep);
if (ByteToHex(comBuffer).Trim() == "06")
{
if (iStep >= 2)
{
}
else
{
byte[] c = new byte[] {
0x02, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31,
0x30, 0x30, 0x30, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x31, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x03,
0x02
};
spBPDione.Write(c, 0, c.Length);
Console.WriteLine("OUT: " + ByteToHex(c));
iStep++;
}
}
else if (ByteToHex(comBuffer).Trim() == "07")
{
byte[] c = new byte[] {
0x04,
};
spBPDione.Write(c, 0, c.Length);
Console.WriteLine("OUT: " + ByteToHex(c));
iStep++;
}
else if (ByteToHex(comBuffer).Trim() == "05")
{
if (iStep >= 2)
{
byte[] c = new byte[] {
0x06,
};
spBPDione.Write(c, 0, c.Length);
Console.WriteLine("OUT: " + ByteToHex(c));
}
}
else if (ByteToHex(comBuffer).Trim().StartsWith("02"))
{
if (iStep >= 2)
{
byte[] c = new byte[] {
0x07,
};
spBPDione.Write(c, 0, c.Length);
Console.WriteLine("OUT: " + ByteToHex(c));
}
}
else if (ByteToHex(comBuffer).Trim() == "04")
{
if (iStep >= 2)
{
byte[] c = new byte[] {
0x06,
};
spBPDione.Write(c, 0, c.Length);
Console.WriteLine("OUT: " + ByteToHex(c));
}
}
}
Now this works and will do what its supposed to on the device it is not very nice clean maintainable code, could i refactor this into a class that follows the following protocol to make the code more readable and OO.
My System DIRECTION Physical Device
ENQ (05) ->
<- ACK0 (06)
STX (message) ETX LRC ->
<- ACK1 (07)
EOT (04) ->
<- ACK0 (06)
<- ENQ (05)
ACK0 (06) ->
<- STX (message) ETX LRC
ACK1 (07) ->
<- EOT (04)
ACK0 (06) ->
|
|
|
|
|
There are many ways to implement a comm protocol, the best one very much depends on the requirements on reliability, robustness and performance. Here are two extremes:
1.
A very easy approach would do everything in a synchronous way, which means NOT using events (e.g. DataReceived); e.g. have a separate thread that basically does what your protocol diagram shows, including some explicit delays:
Write ENQ
Wait 100
Read 1 and check for ACK0
Write STX msg ETX LRC
Wait 100
Read 1 and check for ACK1
...
The waits are necessary if you want a good chance of getting the next input all in one read(buf); if you read too early, you might get a partial message.
Warning: You have to decide what should happen when something unexpected is read!
2.
The general approach would be completely asynchronous, and it would use a state machine, so the DataReceived handler would consist of a big switch on the state variable, and a number of cases each handling one input line of your protocol diagram. Here too you must make sure your diagram is complete, i.e. in each state what should happen if arbitrary stuff is received?
And then you should also take care of time-outs: what when no data at all, or an insufficient amount of data, is received? Your app probably doesn't want to wait forever...
|
|
|
|
|
Thanks Luc.
Is the If / Else block in my code not already doing what you talk about with the State Machine pattern?
|
|
|
|
|
Not really, you are switching/if-ing on the incoming data; a real state machine would switch on its own state (i.e. on what it expects), not on what it gets. What it gets would make it change states.
If you are fortunate enough to have a situation where one party is basically asking questions (e.g. all starting with a different byte value) which the other party is to answer in one message, then that isn't really a protocol, and you obviously can switch on the question, as there then is no state whatsoever.
|
|
|
|
|
Quick question, I have created a class for the message protocol using States I think, i'm just wondering if this is the correct approach:
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.IO.Ports;
namespace TEST
{
public class clsTEST
{
public enum CurrentCommsState
{
Idle,
SentENQ,
RecvdENQ,
SentACK0,
RecvdACK0,
SentACK1,
RecvdACK1,
SentMessage,
RecvdMessage,
SentEOT,
RecvdEOT
}
private enum MessageDirection
{
In,
Out
}
public CurrentCommsState TheState = new CurrentCommsState();
private MessageDirection TheDirection = new MessageDirection();
private SerialPort spTest= null;
private byte[] btRecvdMsg = new byte[200];
public clsOpenShift(SerialPort spTheSP)
{
spTEST= spTheSP;
TheState = CurrentCommsState.Idle;
TheDirection = MessageDirection.Out;
}
public void SendAndRecv(out byte[] TheBufferRecvd)
{
TheBufferRecvd = new Byte[200];
if (SendMsg())
{
if (RecvMsg(ref btRecvdMsg, 1))
{
Array.Copy(btRecvdMsg, TheBufferRecvd, 200);
}
}
else if (RecvMsg(ref btRecvdMsg, 1))
{
if (SendMsg())
{
}
}
}
private bool RecvMsg(ref byte[] btOutRecvd, int iBytesToRecv)
{
bool blnRetVal = false;
try
{
while (spOpenShiftSP.BytesToRead == 0)
{
System.Threading.Thread.Sleep(100);
}
byte[] theBuffer = new byte[iBytesToRecv];
spTEST.Read(theBuffer, 0, iBytesToRecv);
ChangeState(theBuffer);
Array.Copy(theBuffer, btOutRecvd, theBuffer.Length);
blnRetVal = true;
}
catch (Exception e)
{
blnRetVal = false;
}
return blnRetVal;
}
private bool SendMsg()
{
bool blnRetVal = false;
try
{
byte[] btToSend = MessageToSend();
ChangeState(btToSend);
if (btToSend != null)
{
spTEST.Write(btToSend, 0, btToSend.Length);
blnRetVal = true;
}
else
{
blnRetVal = false;
}
}
catch (Exception e)
{
blnRetVal = false;
}
return blnRetVal;
}
private void ChangeState(byte[] theMessage)
{
if (TheState == CurrentCommsState.Idle)
{
TheState = CurrentCommsState.SentENQ;
}
else if (TheState == CurrentCommsState.SentENQ &&string.Compare(ByteToHex(theMessage).Trim(),"THE CORRECT ACK (EITHER 06 or 07)") == 0)
{
}
}
private byte[] MessageToSend()
{
if (TheState == CurrentCommsState.Idle)
{
byte[] ENQ = new byte[] { 0x05 };
return ENQ;
}
else if (TheState == CurrentCommsState.SentENQ)
{
byte[] STX_MSG_ETX_LRC = new byte[] {
0x02, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31,
0x30, 0x30, 0x30, 0x30, 0x31, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x31, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x31, 0x20, 0x20, 0x20,
0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x20, 0x03,
0x02
};
return STX_MSG_ETX_LRC;
}
else if(TheState == CurrentCommsState.SentMessage)
{
byte[] EOT = new byte[] { 0x04 };
return EOT;
}
else if (TheState == CurrentCommsState.SentEOT)
{
return null;
}
else
{
return new byte[1];
}
}
private string ByteToHex(byte[] comByte)
{
StringBuilder builder = new StringBuilder(comByte.Length * 3);
foreach (byte data in comByte)
{
builder.Append(Convert.ToString(data, 16).PadLeft(2, '0').PadRight(3, ' '));
}
return builder.ToString().ToUpper();
}
}
}
I will eventually change the STX_Msg to use Member Vars to populate the correct message not a hardcoded set of values as it is currently.
Also calling the code like so:
byte[] btRecvdMsg = null;
clsTest COMMS = new clsTest(spSerialPort);
while (COMMS.TheState != clsTest.CurrentCommsState.RecvdEOT)
{
COMMS.SendAndRecv(out btRecvdMsg);
System.Threading.Thread.Sleep(100);
}
Am I on the right tracks here?
Thanks in Advance
|
|
|
|
|
Hi Keith,
KeithF wrote: Am I on the right tracks here?
yes, well, maybe. I did not study your code in much detail, I do see a state-machine-like approach, which could be fine; however I have issues in several aspects:
1. I'm not sure I know enough about your "protocol" to judge the approach. As I said, what you need as an implementation heavily depends on your protocol.
e.g. what should happen when an unexpected response is received (say you send an ENQ and then receive an ETX where it "should" have been an ACK)
2. I didn't see your actual transmit and receive operations; is your receiver operating asynchronously (i.e. using a completion event)? or blocking (i.e. just read-and-wait-till-done)?
3. You seem to somewhat merge, then split, inbound and outbound messages; not sure why.
4. Whatever the goals and needs, I'm pretty sure my code would look quite differently, but that is a matter of style. In particular I'm not fond of methods that need data, don't get it as a parameter, and then go fetch it somehow (as your SendMsg-MessageToSend pair is doing).
Here is what I might consider doing if your protocol is somewhat close to what I think you intend:
- I would opt for (pseudo)synchronous transmit and asynchronous receive;
- so I would transmit using SP.Write() and act as if the data is gone instantly (if necessary just include a sleep period that corresponds to the normal transmission time, probably not necessary at all);
- and I would not read except inside the DataReceived handler.
- that would halve the number of states I need, as each state typically would be an "awaiting" state, say "waiting for ACK0";
DataReceived should check the next inbound message;
if it is an ACK0, send a new message (synchronously!), adapt the state (say "waiting for "ACK1"), and return;
if it isn't, send a new message ("aborting"), set state="IDLE" (=waiting for anything), and return;
- so that boils down to a big switch inside DataReceived, switching to the current state (what am I expecting?), then looking at what actually was received, react (probably by sending something) and adapt the state, so the next DataReceived switch will go to another case.
That would work for simple cases; it would not cope well with slow transmission conditions: if you want overlaps (comparable to overlapped file I/O in Windows) or if your state actions are too large to handle in DataReceived itself, you may need a more complex scheme, maybe an input queue, etc.
Hope this helps. But once again, as I said, it all depends on what you need. It would not make sense to create a 1000 LOC class for a thermometer that sends one or two strings per second.
|
|
|
|
|
Dear developers,
Does someone knows how can I iterate all open child forms from the mdi parent
And for each form save the report to one excel file?
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
