I am using SHFileOperationW function with FO_DELETE parameter to move a file to recycle bin (if recycle bin is not disabled).
The problem is when I log as non-admin user and run my application as admin. The files are moved to admin's recycle bin.
Is it possible to make it so the files are moved to the currenly logged non-admin user's recycle bin?
My idea was to run separate non-elevated process and move it to recycle bin from there. But I am not sure if a better solution exists. I tried to find answer on internet, but did not succeed.
I would propose the following routine - tested on Delphi XE 10.
function File2Trash(const FileName: string): boolean;
var
fos: TSHFileOpStruct;
begin
FillChar(fos, SizeOf(fos), 0);
with fos do
begin
wFunc := FO_DELETE;
pFrom := PChar(ExpandFileName(FileName)+#0#0);
fFlags := FOF_ALLOWUNDO or FOF_NOCONFIRMATION or FOF_SILENT or FOF_NOERRORUI;
end;
Result := (0 = ShFileOperation(fos));
end;
Some details are important:
no relative path should be used, existing path should be expanded to
full one;
adding #0#0 to the end of file name is the must;
to keep this operation silent I would propose to use one more flag
FOF_NOERRORUI.
When I needed to use this routine, I used the following commands.
I hope it is useful.
Tests with Delphi 2010 and Windows 8.
procedure TForm2.Button1Click(Sender: TObject);
var
vMsg : string;
begin
// If want permanently delete
//deletefile(edit1.text);
SendFileToTrash(edit1.Text, vMsg);
if (vMsg = '') then
begin
ShowMessage('File sent to the trash.');
end else begin
ShowMessage(vMsg);
end;
end;
procedure TForm2.SendFileToTrash(const aFileName: TFileName; var MsgError: string);
var
Op: TSHFileOpStruct;
begin
{Very importante
Include in Uses SysUtils and ShellAPI;
}
MsgError := '';
if not (FileExists(aFileName)) then
begin
MsgError := 'File not found.';
Exit;
end;
FillChar(Op, SizeOf(Op), 0);
Op.wFunc := FO_DELETE;
Op.pFrom := PChar(aFileName+#0);
Op.fFlags := FOF_ALLOWUNDO or FOF_NOCONFIRMATION or FOF_SILENT;
if (ShFileOperation(Op) <> 0) then
begin
MsgError := 'Could not send the file to the trash.';
end;
end;
Related
Have a set of Word-templates (files *.dot) and a little program, which create new files base on that templates. It's works fine, but the goal is to make all in one exe-file.
I see the solution is to move templates files into program resources. But I don't know, how then I will read them from resources. Tell me, please, how to do this.
Maybe you can advise me another solution.
Now, my code is:
procedure TfmMain.CreateDocument0;
var
TempleateFileName: string;
WordApp, Document: OleVariant;
procedure FillBookmark(BookmarkName, bText: string);
var
Range: OleVariant;
begin
if Document.Bookmarks.Exists(BookmarkName) then
begin
Range := Document.Bookmarks.Item(BookmarkName).Range;
Range.Text := bText;
end;
end;
begin
TempleateFileName := ExtractFilePath(Application.ExeName)+'Templates\0.dot';
try
WordApp := GetActiveOleObject('Word.Application');
except
try
WordApp := CreateOleObject('Word.Application');
except
on E: Exception do
begin
MessageBox(Self.Handle, PChar(E.Message), PChar(fmMain.Caption), MB_OK+MB_ICONERROR);
Exit;
end;
end;
end;
try
Document := WordApp.Documents.Add(TempleateFileName, False);
FillBookmark('ObjectType', edt0ObjectType.Text);
...
WordApp.Visible := True;
WordApp.Activate;
finally
WordApp := Unassigned;
end;
end;
That is, I should change this line:
Document := WordApp.Documents.Add(TempleateFileName, False);
Read not from file, but from program resource.
Word cannot open documents from memory. Not only does it not have such a feature, you must also bear in mind that Word executes in a separate process. It cannot see the memory in your process, even if it were able to open documents from memory.
If you do put the documents into linked resources then you will need to extract them to file before asking Word to open them.
I have a small application that is used to process some files made in another program.
I use an older component by Angus Johnson called TDirectoryWatch
On my FormCreate I have the following code
DirectoryWatch := TDirectoryWatch.Create(self);
DirectoryWatch.OnChange := FileAction;
DirectoryWatch.Directory := Folders.Path(dirInput);
DirectoryWatch.Active := True;
If the program is started and there is put a new file in the directory everything fires and runs OK.
But if there is a file in the directory when the program is started nothing happens even if I make a call to FileAction(nil);
FileAction is the name of the procedure that handles the files
I have a call to FileAction from a popupmenu and that handles the files in the directory
So my question is: how to make sure that existing files are handled at program start?
Or is there a better way to handle this problem.
Added code for FileAction
procedure TfrmMain.FileAction(Sender: TObject);
var
MailFile: string;
MailInfo: TMailInfo;
ListAttachments: TstringList;
i: integer;
MailBody: string;
begin
for MailFile in TDirectory.GetFiles(Folders.Path(dirInput), CheckType) do
begin
if FileExists(MailFile) then
begin
MailInfo := TMailInfo.Create(MailFile);
try
if FileProcessing = False then
begin
Logfile.Event('Behandler fil: ' + MailFile);
FileProcessing := True;
MailBody := '';
Settings.Load;
MailInfo.Load;
Settings.Mail.Signature := '';
Settings.Mail.Subject := MailInfo.Subject;
ListAttachments := TStringList.Create;
ListAttachments.Clear;
for i := 1 to MaxEntries do
begin
if (MailInfo.Attachment[i] <> '') and (FileExists(MailInfo.Attachment[i])) then
ListAttachments.Add(MailInfo.Attachment[i]);
end;
for i := 1 to MaxEntries do
begin
MailBody := MailBody + MailInfo.MailBody[i];
end;
try
if MailBody <> '' then
begin
if MailInfo.SenderBcc then
Mailing.Send(MailInfo.SenderMail, MailInfo.Recipient, MailInfo.SenderMail, MailInfo.Subject, MailBody, ListAttachments, True)
else
Mailing.Send(MailInfo.SenderMail, MailInfo.Recipient, MailInfo.Subject, MailBody, ListAttachments, True);
end;
finally
ListAttachments.Free;
end;
FileProcessing := False;
DeleteFile(MailFile);
end;
finally
MailInfo.Free;
end;
end;
end;
end;
The component doesn't notify about changes when your program starts up because at the time your program starts, there haven't been any changes yet.
Your policy appears to be that at the time your program starts up, all existing files are to be considered "new" or "newly changed," so your approach of manually calling the change-notification handler is correct.
The only thing the component does when it detects a change is to call the change-notification handler. If you explicitly call that function, and yet you still observe that "nothing happens," then there are more deep-seated problems in your program that you need to debug; it's not an issue with the component or with the basic approach described here.
I'm trying to pass information between two of my applications in Delphi 2010.
I'm using a simplified version of code that I've used successfully in the past (simplified because I don't need the sender to know that the send has been successful) I've boiled down the send received to a pair of example applications, which in essence are as follows
Send
procedure TMF.SendString;
var
copyDataStruct: TCopyDataStruct;
s: AnsiString;
begin
s := ebFirm.Text;
copyDataStruct.cbData := 1 + length(s);
copyDataStruct.lpData := PAnsiChar(s);
SendData(copyDataStruct);
end;
procedure TMF.SendData(copyDataStruct: TCopyDataStruct);
var
rh: THandle;
res: integer;
begin
rh := FindWindow(PChar('TMF'), PChar('Get Phone'));
if rh = 0 then
begin
// Launch the target application
ShellExecute(Handle, 'open', GetPhone, nil, nil, SW_SHOWNORMAL);
// Give time for the application to launch
Sleep(3000);
SendData(copyDataStruct); // RECURSION!
end;
SendMessage(rh, WM_COPYDATA, Integer(Handle), Integer(#copyDataStruct));
end;
Receive Application
procedure TMF.WMCopyData(var Msg: TWMCopyData);
var
s : AnsiString;
begin
s := PAnsiChar(Msg.CopyDataStruct.lpData) ;
jobstatus.Panels[1].Text := s;
end;
The major difference between the working test applications and the application I am adding the code to is that there is a lot of extra activity going on in target application. Especially on startup.
Any suggestions on why the WMCopyData procedure seems not to be firing at all?
CHeers
Dan
There are a few problems with your code.
One, you are not assigning a unique ID to the message. The VCL, and various third-party components, also use WM_COPYDATA, so you have to make sure you are actually processing YOUR message and not SOMEONE ELSE'S message.
Two, you may not be waiting long enough for the second app to start. Instead of Sleep(), use ShellExecuteEx() with the SEE_MASK_WAITFORINPUTIDLE flag (or use CreateProcess() and WaitForInputIdle()).
Third, when starting the second app, your recursive logic is attempting to send the message a second time. If that happened to fail, you would launch a third app, and so on. You should take out the recursion altogether, you don't need it.
Try this:
var
GetPhoneMsg: DWORD = 0;
procedure TMF.SendString;
var
copyDataStruct: TCopyDataStruct;
s: AnsiString;
begin
if GetPhoneMsg = 0 then Exit;
s := ebFirm.Text;
copyDataStruct.dwData := GetPhoneMsg;
copyDataStruct.cbData := Length(s);
copyDataStruct.lpData := PAnsiChar(s);
SendData(copyDataStruct);
end;
procedure TMF.SendData(copyDataStruct: TCopyDataStruct);
var
rh: HWND;
si: TShellExecuteInfo;
res: Integer;
begin
rh := FindWindow(PChar('TMF'), PChar('Get Phone'));
if rh = 0 then
begin
// Launch the target application and give time to start
ZeroMemory(#si, SizeOf(si));
si.cbSize := SizeOf(si);
si.fMask := SEE_MASK_WAITFORINPUTIDLE;
si.hwnd := Handle;
si.lpVerb := 'open';
si.lpFile := GetPhone;
si.nShow := SW_SHOWNORMAL;
if not ShellExecuteEx(#si) then Exit;
rh := FindWindow(PChar('TMF'), PChar('Get Phone'));
if rh = 0 then Exit;
end;
SendMessage(rh, WM_COPYDATA, WParam(Handle), LParam(#copyDataStruct));
end;
initialization
GetPhoneMsg := RegisterWindowMessage('TMF_GetPhone');
Receive Application
var
GetPhoneMsg: DWORD = 0;
procedure TMF.WMCopyData(var Msg: TWMCopyData);
var
s : AnsiString;
begin
if (GetPhoneMsg <> 0) and (Msg.CopyDataStruct.dwData = GetPhoneMsg) then
begin
SetString(s, PAnsiChar(Msg.CopyDataStruct.lpData), Msg.CopyDataStruct.cbData);
jobstatus.Panels[1].Text := s;
end else
inherited;
end;
initialization
GetPhoneMsg := RegisterWindowMessage('TMF_GetPhone');
I think it is a good habit to add
copyDataStruct.dwData := Handle;
in procedure TMF.SendString; - if you don't have a custom identifier, putting the source HWND value will help debugging on the destination (you can check for this value in the other side, and therefore avoid misunderstand of broadcasted WMCOPY_DATA e.g. - yes, there should not be, but I've seen some!).
And
procedure WMCopyData(var Msg : TWMCopyData); message WM_COPYDATA;
in TMF client class definition, right?
There should be a missing exit or else after the nested SendData call:
procedure TMF.SendData(copyDataStruct: TCopyDataStruct);
(...)
Sleep(3000);
SendData(copyDataStruct);
end else
SendMessage(rh, WM_COPYDATA, NativeInt(Handle), NativeInt(#copyDataStruct));
end;
But this won't change much.
Check the rh := FindWindow() returned handle: is it the Handle of the TMF client form, or the Application.Handle?
It doesn't work anymore if you are using Windows 7.
If you are using it, check this page to see how to add an exception: http://msdn.microsoft.com/en-us/library/ms649011%28v=vs.85%29.aspx
I thought there was a problem with the (rh) handle being 0 when you call it, if the app needed to be started. But now I see that SendData calls itself recursively. I added a comment in the code for that, as it was non-obvious. But now there's another problem. The 2nd instance of SendData will have the right handle. But then you're going to pop out of that, back into the first instance where the handle is still 0, and then you WILL call SendMessage again, this time with a 0 handle. This probably is not the cause of your trouble, but it's unintended, unnecessary, and altogether bad. IMO, this is a case complicating things by trying to be too clever.
I have code which is used both in services and within VCL Form applications (win32 application). How can I determine if the underlying application is running as a NT Service or as an application?
Thanks.
BEGIN OF EDIT
Since this still seems to be getting some attention I decided to update the answer with missing info and newer windows patches. In any case you should not copy / paste the code. The code is just a showcase on how the things should be done.
END OF EDIT:
You can check if the parent process is SCM (service control manager). If you are running as service this is always the case and never the case if running as standard application. Also I think that SCM has always the same PID.
You can check it like this:
type
TAppType = (atUnknown, atDesktop, atService);
var
AppType: TAppType;
function InternalIsService: Boolean;
var
PL: TProcessList;
MyProcessId: DWORD;
MyProcess: PPROCESSENTRY32;
ParentProcess: PPROCESSENTRY32;
GrandParentProcess: PPROCESSENTRY32;
begin
Result := False;
PL := TProcessList.Create;
try
PL.CreateSnapshot;
MyProcessId := GetCurrentProcessId;
MyProcess := PL.FindProcess(MyProcessId);
if MyProcess <> nil then
begin
ParentProcess := PL.FindProcess(MyProcess^.th32ParentProcessID);
if ParentProcess <> nil then
begin
GrandParentProcess := PL.FindProcess(ParentProcess^.th32ParentProcessID);
if GrandParentProcess <> nil then
begin
Result := SameText(string(ParentProcess^.szExeFile), 'services.exe') and
(SameText(string(GrandParentProcess^.szExeFile), 'winlogon.exe') or
SameText(string(GrandParentProcess^.szExeFile), 'wininit.exe'));
end;
end;
end;
finally
PL.Free;
end;
end;
function IsService: Boolean;
begin
if AppType = atUnknown then
begin
try
if InternalIsService then
AppType := atService
else
AppType := atDesktop;
except
AppType := atService;
end;
end;
Result := AppType = atService;
end;
initialization
AppType := atUnknown;
The TProcessList is implemented like this (again THashTable is not included but any hash table should be fine):
type
TProcessEntryList = class(TList)
private
function Get(Index: Integer): PPROCESSENTRY32;
procedure Put(Index: Integer; const Value: PPROCESSENTRY32);
public
property Items[Index: Integer]: PPROCESSENTRY32 read Get write Put; default;
function Add(const Entry: TProcessEntry32): Integer; reintroduce;
procedure Clear; override;
end;
TProcessList = class
private
ProcessIdHashTable: THashTable;
ProcessEntryList: TProcessEntryList;
public
constructor Create; reintroduce;
destructor Destroy; override;
procedure CreateSnapshot;
function FindProcess(const ProcessId: DWORD): PPROCESSENTRY32;
end;
implementation
{ TProcessEntryList }
procedure TProcessEntryList.Clear;
var
i: Integer;
begin
i := 0;
while i < Count do
begin
FreeMem(Items[i]);
Inc(i);
end;
inherited;
end;
procedure TProcessEntryList.Put(Index: Integer; const Value: PPROCESSENTRY32);
var
Item: Pointer;
begin
Item := inherited Get(Index);
CopyMemory(Item, Value, SizeOf(tagPROCESSENTRY32));
end;
function TProcessEntryList.Get(Index: Integer): PPROCESSENTRY32;
begin
Result := PPROCESSENTRY32(inherited Get(Index));
end;
function TProcessEntryList.Add(const Entry: TProcessEntry32): Integer;
var
EntryCopy: PPROCESSENTRY32;
begin
GetMem(EntryCopy, SizeOf(tagPROCESSENTRY32));
CopyMemory(EntryCopy, #Entry, SizeOf(tagPROCESSENTRY32));
Result := inherited Add(EntryCopy);
end;
{ TProcessList }
constructor TProcessList.Create;
begin
inherited;
ProcessEntryList := TProcessEntryList.Create;
ProcessIdHashTable := THashTable.Create;
end;
destructor TProcessList.Destroy;
begin
FreeAndNil(ProcessIdHashTable);
FreeAndNil(ProcessEntryList);
inherited;
end;
function TProcessList.FindProcess(const ProcessId: DWORD): PPROCESSENTRY32;
var
ItemIndex: Integer;
begin
Result := nil;
if not ProcessIdHashTable.ContainsKey(IntToStr(ProcessId)) then
Exit;
ItemIndex := Integer(ProcessIdHashTable.Item[IntToStr(ProcessId)]);
Result := ProcessEntryList.Items[ItemIndex];
end;
procedure TProcessList.CreateSnapshot;
var
SnapShot: THandle;
ProcessEntry: TProcessEntry32;
ItemIndex: Integer;
begin
SnapShot := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if SnapShot <> 0 then
try
ProcessEntry.dwSize := SizeOf(ProcessEntry);
if Process32First(SnapShot, ProcessEntry) then
repeat
ItemIndex := ProcessEntryList.Add(ProcessEntry);
ProcessIdHashTable.Add(IntToStr(ProcessEntry.th32ProcessID), TObject(ItemIndex));
until not Process32Next(SnapShot, ProcessEntry);
finally
CloseHandle(SnapShot);
end;
end;
The application object (Forms.application) mainform will be nil if it is not a forms based application.
uses
Forms, ... ;
function IsFormBased : boolean;
begin
Result := Assigned(Forms.Application.MainForm);
end;
How about matching GetCurrentProcessId against EnumServicesStatusEx?
The lpServices parameter points to a buffer that receives an array of ENUM_SERVICE_STATUS_PROCESS structures.
The match is done against the enumerated service process ID: ServiceStatusProcess.dwProcessId in that structure.
Another option is using WMI to query for Win32_Service instances where ProcessId=GetCurrentProcessId.
I doubt that
System.IsConsole
System.IsLibrary
will give you the expected results.
All I can think of is to pass an Application object as TObject to the method where you need to make that distinction and test for the passed object's classname being a
TServiceApplication
or
TApplication
That said, there shouldn't be a need for you to know if your code is running in a service or a GUI. You should probably rethink your design and make the caller to pass an object to handle messages you want (or don't want) to show. (I assume it is for showing messages/exceptions you'd like to know).
You can try something like this
Function IsMyformInsideaWindowsService(aForm:TObject) :Boolean;
Begin
Result:=aForm.ClassParent.ClassName='TService'; //When a form is running under a service the Class Parent is a TService
End;
A single project cannot (or I should say ideally is not) both a service and a forms application, at least not if you are able to distinguish between the Forms Application object and the SvcMgr Application object - you must presumably have separate projects for the forms code and the service code.
So perhaps the easiest solution is a project conditional define. i.e. in your project settings for the service project add "SERVICEAPP" to the Conditional Defines.
Then whenever you need to change behaviour simply:
{$ifdef SERVICEAPP}
{$else}
{$endif}
For belts and braces you might adopt one of the previously described tests within some startup code to ensure that your project has been compiled with the expected symbol defined.
program ... ;
:
begin
{$ifdef SERVICEAPP}
// test for service app - ASSERT if not
{$else}
// test for forms app - ASSERT if not
{$endif}
:
end.
It is possible that your Forms app is actually running as a service, using the crude technique that allows any application to be running as a service.
In that case of course your app will always be a Forms application and the easiest way to handle that situation is to have a command line switch that you specify only in the service definition for your executable so that your app can respond appropriate by testing for that command line switch.
This does allow you to more easily test your "service mode" behaviour of course, since you can run your app in "debug" mode with that switch defined from within the IDE, but it's not an ideal way to build a service application so I would not recommend it on the strength of that alone. It's a technique that is usually only used when you have an EXE that you wish to run as a service but have no way to modify the source code to turn it into a "proper" service.
The answer from "Runner" ( https://stackoverflow.com/a/1568462 ) looked very helpful, but I could not use it since neither TProcessList, nor CreateSnapshot is defined. Searching for "TProcessList CreateSnapshot" in Google will just find 7 pages, including this one and mirrors/quotes of this page. No code exists. Alas, my reputation is too low to send him a comment, asking where I can find the code of TProcessList.
Another problem: At my computer (Win7 x64), the "services.exe" is NOT inside "winlogon.exe". It is inside "wininit.exe". Since it seems to be an implementation detail of Windows, I would suggest not querying the grand parent. Also, services.exe does not need to be the direct parent, since processes could be forked.
So this is my version using TlHelp32 directly, solving all the problems:
uses
Classes, TlHelp32;
function IsRunningAsService: boolean;
function FindProcess(FSnapshotHandle: THandle; PID: DWORD; var lppe: TProcessEntry32): boolean;
var
ContinueLoop: BOOL;
begin
ContinueLoop := Process32First(FSnapshotHandle, lppe);
while Integer(ContinueLoop) <> 0 do
begin
if lppe.th32ProcessID = PID then
begin
result := true;
Exit;
end;
ContinueLoop := Process32Next(FSnapshotHandle, lppe);
end;
result := false;
end;
var
CurProcessId: DWORD;
FSnapshotHandle: THandle;
FProcessEntry32: TProcessEntry32;
ExeName, PrevExeName: string;
DeadlockProtection: TList<Integer>;
begin
Result := false;
FSnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
DeadlockProtection := TList<Integer>.Create;
try
CurProcessId := GetCurrentProcessId;
FProcessEntry32.dwSize := SizeOf(FProcessEntry32);
ExeName := '';
while FindProcess(FSnapshotHandle, CurProcessId, FProcessEntry32) do
begin
if DeadlockProtection.IndexOf(FProcessEntry32.th32ProcessID) > -1 then break;
DeadlockProtection.Add(FProcessEntry32.th32ProcessID);
PrevExeName := ExeName;
ExeName := FProcessEntry32.szExeFile;
(*
Result := SameText(PrevExeName, 'services.exe') and // Parent
SameText(ExeName, 'winlogon.exe'); // Grandparent
*)
Result := SameText(ExeName, 'services.exe'); // Parent
if Result then Exit;
CurProcessId := FProcessEntry32.th32ParentProcessID;
end;
finally
CloseHandle(FSnapshotHandle);
DeadlockProtection.Free;
end;
end;
This code works, also even in applications without MainForm (e.g. CLI apps).
you can use GetStdHandle method for get out console handle.when applications run as windows service has not output console.if GetStdHandle equals zero means your application run as windows service.
{$APPTYPE CONSOLE} // important
uses
uServerForm in 'uServerForm.pas' {ServerForm},
uWinService in 'uWinService.pas' {mofidWinServer: TService},
Windows,
System.SysUtils,
WinSvc,
SvcMgr,
Forms,etc;
function RunAsWinService: Boolean;
var
H: THandle;
begin
if FindCmdLineSwitch('install', ['-', '/'], True) then
Exit(True);
if FindCmdLineSwitch('uninstall', ['-', '/'], True) then
Exit(True);
H := GetStdHandle(STD_OUTPUT_HANDLE);
Result := H = 0;
end;
begin
if RunAsWinService then
begin
SvcMgr.Application.Initialize;
SvcMgr.Application.CreateForm(TmofidWinServer, mofidWinServer);
SvcMgr.Application.Run;
end
else
begin
Forms.Application.Initialize;
Forms.Application.CreateForm(TServerForm, ServerForm);
Forms.Application.Run;
end;
end.
I didn't find the simple answer which can be used easily and does not require recompilation and allows using one exe as a service and an application. You can install your program as a service with the command line parameter like “…\myapp.exe –s” and then check it from the program:
if ParamStr(ParamCount) = '-s' then
You can base the check on checking the session ID of the current process. All services runs with session ID = 0.
function IsServiceProcess: Boolean;
var
LSessionID, LSize: Cardinal;
LToken: THandle;
begin
Result := False;
LSize := 0;
if not OpenProcessToken(GetCurrentProcess, TOKEN_QUERY, LToken) then
Exit;
try
if not GetTokenInformation(LToken, TokenSessionId, #LSessionID, SizeOf(LSessionID), LSize) then
Exit;
if LSize = 0 then
Exit;
Result := LSessionID = 0;
finally
CloseHandle(LToken);
end;
end;
I actually ended up checking the application.showmainform variable.
The problem with skamradt's isFormBased is that some of this code is called before the main form is created.
I am using a software library called SvCom_NTService from aldyn-software. One of purposes is for errors; either to log them or show a message. I totally agree with #Rob; our code should be better maintained and handle this outside of the functions.
The other intention is for failed database connections and queries; I have different logic in my functions to open queries. If it is a service then it will return nil but continue the process. But if failed queries/connections occur in an application then I would like to display a messaage and halt the application.
Check if your Applicatoin is an instance of TServiceApplication:
IsServiceApp := Application is TServiceApplication;
I need to know if my program can write files to the disk (HDD, floppy, flash, CD) from where it is running.
I have tried something like:
{$I-}
Rewrite(myFile);
{$I+}
Result:= (IOResult = 0);
The problem is that if the disk is read-only, Windows gives me an error message telling me that
"appName.exe - Write Protect Error The disk cannot be written to because it is write protected. Please remove the write protection from the volume
USB_BOOT in drive D:. Cancel TryAgain Continue"
How can I test for write access without raising any error/warning messages?
Thanks.
Edit:
Ok. The "bug" has nothing to do with the above mentioned piece of code. I only thought that it appears there. I move the code to the read-only disk and ran it from there. The bug appears in a function called "CreateShortcutEx", on this line:
MyPFile.Save(PWChar(WFileName),False);
MyPFile is declared like this:
var
MyObject : IUnknown;
MySLink : IShellLink;
MyPFile : IPersistFile;
Directory : String;
WFileName : WideString;
MyReg : TRegIniFile;
begin
MyObject := CreateComObject(CLSID_ShellLink);
MySLink := MyObject as IShellLink;
MyPFile := MyObject as IPersistFile;
.....
end;
So, why is MyPFile trying to write to the application's drive (the one that is read-only) if the WFileName parameter is "C:\documents and settings\bla bla" ?
Call the Windows API SetErrorMode() function to disable the error message box.
Edit:
I just tried, and this:
procedure TForm1.Button1Click(Sender: TObject);
var
Str: TStream;
OldMode: Cardinal;
begin
OldMode := SetErrorMode(SEM_FAILCRITICALERRORS);
try
try
Str := TFileStream.Create('z:\foo.txt', fmOpenReadWrite);
try
finally
Str.Free;
end;
except end;
finally
SetErrorMode(OldMode);
end;
end;
works as expected.
Not really pretty but this seems to work for me.
function CanWrite(drive: string): boolean;
var
OldMode: Cardinal;
begin
OldMode := SetErrorMode(SEM_FAILCRITICALERRORS);
try
with TStringList.Create do
try
SaveToFile(drive + ':\file.txt');
result := true;
try
deletefile(drive + ':\file.txt');
except
end;
except
result := false;
end;
finally
SetErrorMode(OldMode);
end;
end;
Call to it with
if CanWrite('g') = true then
begin
showmessage('Can Write');
end
else
begin
showmessage('Can not write');
end;
What happens when you put your code inside an try/except?
Also, you can try (something like) this:
function CanWrite: boolean;
begin
result := true;
with TStringList.Create do
try
SaveToFile('file.txt');
except
result := false;
finally
Free;
end;
end;
Sorry, but I don't code in Delphi anymore and I don't have Delphi installed anywhere.
There exist a small freeware "Drive ready?" utility (dready.com) written by Horst Schaeffer that also can check write access. I have not tested it but as far as I can see this could be used as a solution; call it for instance as "DREADY C: /W" and check the return value.