Title: ShellExecute
Question: Ever wanted to open a .doc in Word? Or a .htm in Internet Explorer? Then you should use ShellExecute:
Answer:
HINSTANCE ShellExecute(
HWND hwnd,
// Handle to parent window, usually self.Handle
LPCTSTR lpOperation,
// pointer to string that specifies operation to perform
// Possible values are:
// 'open' : Open File
// 'print' : Print file
// 'explore': The function explores the
// folder specified by lpFile.
LPCTSTR lpFile,
// pointer to filename or folder name string
LPCTSTR lpParameters,
// pointer to string that specifies executable-file parameters
LPCTSTR lpDirectory,
// pointer to string that specifies default directory
INT nShowCmd
// whether file is shown when opened. You have a lot of options.
// Among them are:
// SW_HIDE, SW_SHOWDEFAULT, SW_SHOWMINIMIZED and so on...
);
Ready-To-Use function:
This function simplifies the use of ShellExecute, and is able to raise and exception depending on the error:
uses
ShellApi;
function ShellOpenFile( hWnd : HWND; AFileName, AParams, ADefaultDir : string ) : integer;
begin
result := shellapi.ShellExecute( hWnd, 'open', pChar( AFileName ),
pChar(AParams),
pChar(ADefaultDir),
SW_SHOWDEFAULT );
case result of
0 :
raise Exception.Create( 'The operating system is out of memory or resources.' );
ERROR_FILE_NOT_FOUND :
raise Exception.Create( 'The specified file was not found.' );
ERROR_PATH_NOT_FOUND :
raise Exception.Create( 'The specified path was not found.' );
ERROR_BAD_FORMAT :
raise Exception.Create( 'The .EXE file is invalid (non-Win32 .EXE or error ' +
'in .EXE image).' );
SE_ERR_ACCESSDENIED :
raise Exception.Create( 'The operating system denied access to the specified file.' );
SE_ERR_ASSOCINCOMPLETE :
raise Exception.Create( 'The filename association is incomplete or invalid.' );
SE_ERR_DDEBUSY :
raise Exception.Create( 'The DDE transaction could not be completed because ' +
'other DDE transactions were being processed.' );
SE_ERR_DDEFAIL :
raise Exception.Create( 'The DDE transaction failed.' );
SE_ERR_DDETIMEOUT :
raise Exception.Create( 'The DDE transaction could not be completed because the ' +
'request timed out.' );
SE_ERR_DLLNOTFOUND :
raise Exception.Create( 'The specified dynamic-link library was not found.' );
SE_ERR_NOASSOC :
raise Exception.Create( 'There is no application associated with the given ' +
'filename extension.' );
SE_ERR_OOM :
raise Exception.Create( 'There was not enough memory to complete the operation.' );
SE_ERR_SHARE :
raise Exception.Create( 'A sharing violation occurred.' );
else
end;
end;
Usage:
hWnd: Handle to owner window. Usually you would use self.Handle.
AFileName: Name of file to be opened.
AParams: Additional parameters.
ADefaultDir: The default (working) directory.
Examples
// Opens applog.txt in the notepad:
ShellOpenFile( self.Handle, 'c:\applog.txt', '', '' );
// Opens the document in Word:
ShellOpenFile( self.Handle, 'mydoc.doc', '', '' );
// Opens a web page in the default browser:
ShellOpenFile( self.Handle, 'http://www.caos.dk', '', '' );
// Opens your default e-mail client
ShellOpenFile( self.Handle, 'mailto:caos@caos.dk', '', '' );