nice one

When i'm using these api's instead of a shell command.In my application when a user clicks a button it executes a command which kicks off a data copy. The problem I have is the data copy can take in upwards of 30 minutes to complete. Durring this time the executable is waiting for the command window to close, then pops a box saying the copy is complete. While the copy is happening the executable is tied up and the user cannot do anything till it is finished. How can I free it up in case the user wants to cancel the copy.

The API's is:
Declare Function WaitForSingleObject Lib _
"kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds _
As Long) As Long

Declare Function CreateProcessA Lib "kernel32" _
(ByVal lpApplicationName As Long, ByVal lpCommandLine As _
String, ByVal lpProcessAttributes As Long, ByVal _
lpThreadAttributes As Long, ByVal bInheritHandles As Long, _
ByVal dwCreationFlags As Long, ByVal lpEnvironment As Long, _
ByVal lpCurrentDirectory As Long, lpStartupInfo As _
STARTUPINFO, lpProcessInformation As PROCESS_INFORMATION) _
As Long
Declare Function CloseHandle Lib "kernel32" (ByVal hObject _
As Long) As Long

and the function is :
Public Sub ExecCmd(cmdline$)
Dim proc As PROCESS_INFORMATION
Dim start As STARTUPINFO
'Initialize the STARTUPINFO structure:
start.cb = Len(start)
start.dwFlags = STARTF_USESHOWWINDOW
start.wShowWindow = SW_HIDE
'Start the shelled application:
ret& = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _
NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc)
Call waiting_process
'Wait for the shelled application to finish:
ret& = WaitForSingleObject(proc.hProcess, INFINITE)
ret& = CloseHandle(proc.hProcess)
End Sub

Add a DoEvents and the user can be able to press cancel.

Code:

---

Declare Function WaitForSingleObject Lib _
"kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds _
As Long) As Long

Declare Function CreateProcessA Lib "kernel32" _
(ByVal lpApplicationName As Long, ByVal lpCommandLine As _
String, ByVal lpProcessAttributes As Long, ByVal _
lpThreadAttributes As Long, ByVal bInheritHandles As Long, _
ByVal dwCreationFlags As Long, ByVal lpEnvironment As Long, _
ByVal lpCurrentDirectory As Long, lpStartupInfo As _
STARTUPINFO, lpProcessInformation As PROCESS_INFORMATION) _
As Long
Declare Function CloseHandle Lib "kernel32" (ByVal hObject _
As Long) As Long


Public Sub ExecCmd(cmdline$)
Dim proc As PROCESS_INFORMATION
Dim start As STARTUPINFO
'Initialize the STARTUPINFO structure:
start.cb = Len(start)
start.dwFlags = STARTF_USESHOWWINDOW
start.wShowWindow = SW_HIDE
'Start the shelled application:
ret& = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _
NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc)
DoEvents 'maybe somewhere here?
Call waiting_process
'Wait for the shelled application to finish:
ret& = WaitForSingleObject(proc.hProcess, INFINITE)
ret& = CloseHandle(proc.hProcess)
End Sub

---

And incase your wondering how I got the code to come out like that: [code]Your code[/code].

How can i unfreeze it while processing

DoEvents should keep the program from freezing. Try adding the DoEvents to a few more places in the code.

It's because, while the shell is processing, the cursor always stays at the same line till the processing is finish,
(ret& = WaitForSingleObject(proc.hProcess, INFINITE)).

See Here, i showed how to add the DoEvents:

Or, if you don't like cross-threading:

Code:

---

'Module code
Private Type STARTUPINFO
cb As Long
lpReserved As String
lpDesktop As String
lpTitle As String
dwX As Long
dwY As Long
dwXSize As Long
dwYSize As Long
dwXCountChars As Long
dwYCountChars As Long
dwFillAttribute As Long
dwFlags As Long
wShowWindow As Integer
cbReserved2 As Integer
lpReserved2 As Long
hStdInput As Long
hStdOutput As Long
hStdError As Long
End Type

Private Type PROCESS_INFORMATION
hProcess As Long
hThread As Long
dwProcessID As Long
dwThreadID As Long
End Type

Private Declare Function WaitForSingleObject Lib _
"kernel32" (ByVal hHandle As Long, ByVal dwMilliseconds _
As Long) As Long

Declare Function CreateProcessA Lib "kernel32" _
(ByVal lpApplicationName As Long, ByVal lpCommandLine As _
String, ByVal lpProcessAttributes As Long, ByVal _
lpThreadAttributes As Long, ByVal bInheritHandles As Long, _
ByVal dwCreationFlags As Long, ByVal lpEnvironment As Long, _
ByVal lpCurrentDirectory As Long, lpStartupInfo As _
STARTUPINFO, lpProcessInformation As PROCESS_INFORMATION) _
As Long

Declare Function CloseHandle Lib "kernel32" (ByVal hObject _
As Long) As Long

Private Const NORMAL_PRIORITY_CLASS = &H20&
Private Const INFINITE = &HFFFF
'-------Start New Code-------
Private Const WAIT_TIMEOUT = &H102
'-------End New Code---------


'Form code
Public Sub ExecCmd(cmdline$)
Dim proc As PROCESS_INFORMATION
Dim start As STARTUPINFO

'Initialize the STARTUPINFO structure:
start.cb = Len(start)

'Start the shelled application:
ret& = CreateProcessA(0&, cmdline$, 0&, 0&, 1&, _
NORMAL_PRIORITY_CLASS, 0&, 0&, start, proc)

'Wait for the shelled application to finish:
' our program from appearing to lock up while it waits.
'-------Start New Code-------
Do
    DoEvents
    ret& = WaitForSingleObject(proc.hProcess, 0)
Loop While ret& = WAIT_TIMEOUT
'-------End New Code---------
ret& = CloseHandle(proc.hProcess)
End Sub

---