See the code snippets below. My problem is as follows:
- TCricketLiveScoringClient creates an instance of TTXProcessThread
- In the Execute method it fires off the NewDataEvent() in the TCricketLiveScoringClient
- The NewDataEvent() then calls TCricketLiveScoringClient.ProcessTX() which uses a MIDAS socket connection to execute a mthod call of ProcessTX
The above however results in an "Error Reading From Socket" as soon as TCricketLiveScoringClient.ProcessTX() executes the MIDAS call. If I call TCricketLiveScoringClient.ProcessTX() in the context of the main application thread then all is well. So it appears to me that there is a problem when we cross thread boundaries. Can someone shed any light on this for me?
TIA
TTXProcessThread = class(TThread)
private
FDatabase : TDataBase;
FLastTxIDProcessed : integer;
FTXTable : TTable;
FNewTXDataEvent : TNewTXDataEvent;
protected
procedure Execute; override;
public
constructor Create(CreateSuspended : Boolean; ADBPath : string;
AStartTXID : integer; ANewTXData : TNewTXDataEvent);
destructor Destroy; override;
end;
procedure TTXProcessThread.Execute;
////////////////////////////////////////////////////////////////////////////////
// PURPOSE: Main workhorse of the thread. It essentially looks for the next id
// in the table. Should it find it then it fires off an event with the info
// and then waits to ensure that things happened OK before proceeding round again
var
EventCompleted : boolean;
EventCompletedSuccessfully : boolean;
begin
// inherited;
while not Terminated do
begin
with FTXTable do
begin
try
if Locate('ID', FLastTxIDProcessed + 1, []) then
begin
//We have found the next TX
//Fire off an event with this info
FNewTXDataEvent(FLastTxIDProcessed + 1, FieldByName('SQLData').AsString, EventCompleted, EventCompletedSuccessfully);
while not EventCompleted do
Application.ProcessMessages;
//The event completed.
//Check to see whether it was successful
if EventCompletedSuccessfully then
Inc(FLastTxIDProcessed);
end;
except
on E : Exception do
ShowMessage(E.Message);
end;
end;
end;
end;
type
TCricketLiveScoringClient = class(TCustomPanel)
private
procedure NewDataEvent(ATXID : integer; ATXPayload : string;
var EventCompleted : boolean; var EventCompletedSuccessfully : boolean);
protected
public
function ProcessTX(AGlobalMatchCode : string; ATXID : Integer;
const ATXPayload : string; var ANextTXID : Integer) : WordBool;
published
property Active : boolean read FActive write SetActive;
property DBPath : string read FDBPath write FDBPath;
property MidasServerAddress : string read FMidasServerAddress write SetMidasServerAddress;
property MidasServerPort : SmallInt read FMidasServerPort write SetMidasServerPort;
end;
function TCricketLiveScoringClient.ProcessTX(AGlobalMatchCode : string; ATXID : Integer;
const ATXPayload : string; var ANextTXID : Integer) : WordBool;
////////////////////////////////////////////////////////////////////////////////
// PURPOSE: Processes the supplied TX information
var
LocalNextTXID : integer;
begin
//Show failure at this point
result := FALSE;
try
//TESTING
// if ATXID <> (FLastTXProcessed + 1) then
// raise ECricketLiveScoringClient.Create('TX is not the next in sequence.');
if FSocketConnection.AppServer.ProcessTX(FClientIP, AGlobalMatchCode, ATXID,
ATXPayload, LocalNextTXID) = WordBool(TRUE) then
begin
result := TRUE;
FLastTXProcessed := ANextTXID - 1;
end;
except
on E : Exception do
raise ECricketLiveScoringClient.Create(E.Message);
end;
end;
procedure TCricketLiveScoringClient.NewDataEvent(ATXID : integer; ATXPayload : string;
var EventCompleted, EventCompletedSuccessfully : boolean);
////////////////////////////////////////////////////////////////////////////////
// PURPOSE: Fired when new data is detected in the TX table
var
NextTXID : integer;
begin
//Show that things are just started
EventCompleted := FALSE;
EventCompletedSuccessfully := FALSE;
try
try
//Try and process the TX Line
if not ProcessTX(FGlobalMatchCode, ATXID, ATXPayload, NextTXID) then
raise ECricketLiveScoringClient.Create('I could not processs TXID ' + IntToStr(ATXID));
finally
//Show that event has completed
EventCompleted := TRUE;
end;
//We got this far so things were successful
EventCompletedSuccessfully := TRUE;
except
on E : Exception do
raise ECricketLiveScoringClient.Create(E.Message);
end;
end;
----------------------------------------------------------------------
Donovan J. Edye [www.edye.wattle.id.au]
Namadgi Systems [www.namsys.com.au]
Voice: +61 2 6285-3460
Fax: +61 2 6285-3459
TVisualBasic = Class(None);
Heard just before the 'Big Bang': "...Uh Oh...."
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