The application called an interface that was marshalled for a different thread
- by X-Ray
i'm writing a delphi app that communicates with excel. one thing i noticed is that if i call the Save method on the Excel workbook object, it can appear to hang because excel has a dialog box open for the user. i'm using the late binding.
i'd like for my app to be able to notice when Save takes several seconds and then take some kind of action like show a dialog box telling this is what's happening.
i figured this'd be fairly easy. all i'd need to do is create a thread that calls Save and have that thread call Excel's Save routine. if it takes too long, i can take some action.
procedure TOfficeConnect.Save;
var
Thread:TOfficeHangThread;
begin
// spin off as thread so we can control timeout
Thread:=TOfficeSaveThread.Create(m_vExcelWorkbook);
if WaitForSingleObject(Thread.Handle, 5 {s} * 1000 {ms/s})=WAIT_TIMEOUT then
begin
Thread.FreeOnTerminate:=true;
raise Exception.Create(_('The Office spreadsheet program seems to be busy.'));
end;
Thread.Free;
end;
TOfficeSaveThread = class(TThread)
private
{ Private declarations }
m_vExcelWorkbook:variant;
protected
procedure Execute; override;
procedure DoSave;
public
constructor Create(vExcelWorkbook:variant);
end;
{ TOfficeSaveThread }
constructor TOfficeSaveThread.Create(vExcelWorkbook:variant);
begin
inherited Create(true);
m_vExcelWorkbook:=vExcelWorkbook;
Resume;
end;
procedure TOfficeSaveThread.Execute;
begin
m_vExcelWorkbook.Save;
end;
i understand this problem happens because the OLE object was created from another thread (absolutely).
how can i get around this problem? most likely i'll need to "re-marshall" for this call somehow...
any ideas?
thank you!
