我想通过程序来实现卸载U盘的操作？如何来实现？？

[喜欢编程朋友]

我想通过程序来实现卸载U盘的操作？这样就不用手动点击右下角的卸载操作了。
如何来实现？？请高手指点！！！！！！

[喜欢编程朋友]

ding

[elite01]

要了解

[hbczlp]

up

[puppy52020]

http://www.yeahware.com/download/eject.zip
选择Show hidden device后在USB Mass Storage Device处就是Eject了！！！

关键代码

function CM_Get_DevNode_Status(pulStatus: PULong; pulProblemNumber: PULong;
dnDevInst: DWord; ulFlags: ULong): DWord; stdcall;
external CfgMgr32ModuleName name 'CM_Get_DevNode_Status';

function CM_Request_Device_Eject(dnDevInst: DWord; out pVetoType: TPNPVetoType;
pszVetoName: PChar; ulNameLength: ULong; ulFlags: ULong): DWord; stdcall;
external SetupApiModuleName name 'CM_Request_Device_EjectA';


if (CM_Get_DevNode_Status(@Status, @Problem, DeviceInfoData.DevInst, 0) <> CR_SUCCESS) then
begin
exit;
end;
VetoName[0] := #0;
case CM_Request_Device_Eject(DeviceInfoData.DevInst, VetoType, @VetoName, SizeOf(VetoName), 0) of
CR_SUCCESS:
begin
MessageBox(Handle, PChar(’Eject OK (Veto: ' + VetoName + ')'), 'Vetoed', MB_OK); end;
CR_REMOVE_VETOED:
begin
MessageBox(Handle, PChar('Failed to eject the Device (Veto: ' + VetoName + ')'), 'Vetoed', MB_OK);
end;
else
begin
MessageBox(Handle, PChar('Failed to eject the Device (' + SysErrorMessage(GetLastError) + ')'), 'Failure', MB_OK);
end;
end;

那个Eject原代码是有Bug的，修正如下

添加
function TForm1.GetDevInfo(var hDevInfo: hDevInfo): boolean;
begin
// Get a handle to all devices in all classes present on system
hDevInfo := SetupDiGetClassDevs(nil, nil, 0, DIGCF_PRESENT or DIGCF_ALLCLASSES);
Result := hDevInfo <> Pointer(INVALID_HANDLE_VALUE);
end;

调用为：
procedure TForm1.FormCreate(Sender: TObject);
begin
if (not LoadSetupAPI) then
begin
ShowMessage('Could not load SetupAPI.dll');
exit;
end;
DevInfo := nil;
ShowHidden := false;
// Get a handle to all devices in all classes present on system
if not GetDevInfo(DevInfo) then
begin
ShowMessage('GetClassDevs');
exit;
end;
// Get the Images for all classes, and bind to the TreeView
ClassImageListData.cbSize := SizeOf(TSPClassImageListData);
if (not SetupDiGetClassImageList(ClassImageListData)) then
begin
ShowMessage('GetClassImageList');
exit;
end;
ImageList.Handle := ClassImageListData.ImageList;
TreeView.Images := ImageList;
// Add the devices to the TreeView window.
EnumAddDevices(ShowHidden, TreeView, DevInfo);
end;

procedure TForm1.mRefreshDisplayClick(Sender: TObject);
begin
if not GetDevInfo(DevInfo) then
begin
ShowMessage('GetClassDevs');
exit;
end;
EnumAddDevices(ShowHidden, TreeView, DevInfo);
end;

case CM_Request_Device_Eject(DeviceInfoData.DevInst, VetoType, @VetoName, SizeOf(VetoName), 0) of
CR_SUCCESS:
begin
MessageBox(Handle, 'Successful to eject the Device', 'Done', MB_OK);
if not GetDevInfo(DevInfo) then
begin
ShowMessage('GetClassDevs');
exit;
end;
EnumAddDevices(ShowHidden, TreeView, DevInfo);
end;