C # Call bits (Background Intelligent Transfer Service)

BITs (Background Intelligent Transfer Service) is a technology launched by Microsoft to implement file transmission between the client and server. Microsoft only provides com-based interfaces, rather than hosting-based interfaces. Code . If you want to use a. Net Language (such as C #), you need to manually encapsulate the COM interface or use a third-party encapsulation. BITs has multiple versions, which makes it more difficult to find a suitable one. Msdoes not have a pure TLB file or embed the TLB file into the real-time bits's dll. you cannot use tlbimp.exe to generate com packages. If a TLB file exists, you can use tlbimp.exe to generate com packages. Program Set.

I found that the packaging assembly can be generated by viewing the file windows supervisor, but there is a problem that no matter which version of The IDL file is used, only the packaging assembly of the COM interface of BITs 1.0 can be generated; in addition, if bits4_0.idl is used to generate a packaging class, an exception occurs when you create a backgroundcopymanager4_0class object and experiment on two win7 machines. The exception information is:
Retrieving the com class factory for component with clsid {BB6DF56B-CACE-11DC-9992-0019B93A3A84} failed due to the following error: 80080005.
I have not found a solution for the moment. I doubt it is a Ms bug.

If 4.0 is unavailable, only 3.0 of the Packaged assembly can be generated. The following procedure is performed on the bits3_0.idl file:Library backgroundcopymanager3_0
{
[
UUID (659cdea7 - 489e - 11d9 - A9cd - 000d000065133 ),
Helpstring ( " Background copy Manager 3.0 " )
]
Coclass backgroundcopymanager3_0
{
[ Default ] Interface Ibackgroundcopymanager;
};
Interface Ibackgroundcopyjob4;

InterfaceIbackgroundcopyjobhttpoptions;
InterfaceIbackgroundcopycallback2;
InterfaceIbackgroundcopyfile3;
InterfaceIbitspeercacheadministration;
}

The purpose of this interface is to include the interfacepacket in the interface when generating the TLB file. tlbimp.exe encapsulates these interfaces.
Command Behavior:Midl bits3_0.IDL
Tlbimp bits3_0.TLB

Generate the backgroundcopymanager3_0.dll file and add reference to the. NET project. If you want to obtain an interface of a higher version from an interface of a lower version, you need an interface of a lower version to call QueryInterface. However, the packaging of the COM interface will shield reference counting and QueryInterface. The system. runtime. interopservices namespace will show that there is a QueryInterface method in the marshal class:Public Static IntQueryInterface (intptr punk,RefGuid IID,OutIntptr BPPV );

Solve this problem.

Test the Code:UsingSystem;
UsingSystem. runtime. interopservices;
UsingBackgroundcopymanager3_0;

Namespace Www. xianfen. net
{
Class Program
{
Static Void Main ( String [] ARGs)
{
Backgroundcopymanager3_0class Mgr = New Backgroundcopymanager3_0class ();
Guid;
Ibackgroundcopyjob job;

// create job
Mgr. createjob ( " job " , bg_job_type.bg_job_type_download, out guid, out job );

// guid of The New Interface version.
guid gjob4 = New GUID ( " 659cdeae-489e-11d9-a9cd-000d000065133 " );

// get the pointers of interfaces of earlier versions
intptr punknwjob = marshal. getiunknownforobject (job);
intptr punknwjob4;

// get the pointer of The New Interface version
int hresult = marshal. queryInterface (punknwjob, ref gjob4, out punknwjob4 );

// get the new version of the interface instance
ibackgroundcopyjob4 job4 = (ibackgroundcopyjob4) marshal. getobjectforiunknown (punknwjob4);

Job4.addfile ("Http://www.xianfen.net/GRMSDKX_EN_DVD.iso","C: \ winsdk. ISO");
Job4.setpriority (bg_job_priority.bg_job_priority_foreground );
//Various operations...
}
}
}

Download: Download the modified bits3_0.idl and TLB files and assembly