I have a WinForms application. Just before creating the actual form in Program.cs, I instantiate an Autoplay class. Registration is successful, after the obligatory first return value of 65536, but I never get any calls to AllowAutoPlay().
Am I missing something?
Here is the code:
public class RunningObjectTableEntry : IDisposable
{
private const int ROTFLAGS_REGISTRATIONKEEPSALIVE = 1;
private HRESULT cookie;
private IRunningObjectTable rot = null;
private IMoniker monkey = null;
private RunningObjectTableEntry() { }
public RunningObjectTableEntry(object obj)
{
this.AddToROT(obj);
}
public void AddToROT(object obj)
{
int hr = GetRunningObjectTable(0, out rot);
if (hr != 0)
{
throw new COMException("Could not retrieve running object table!", hr);
}
Guid clsid = obj.GetType().GUID;
hr = CreateClassMoniker(ref clsid, out monkey);
if (hr != 0)
{
Marshal.ReleaseComObject(rot);
throw new COMException("Could not create moniker for CLSID/IID \"" + clsid + "\"!", hr);
}
UInt32 iResult = (UInt32)rot.Register(ROTFLAGS_REGISTRATIONKEEPSALIVE, obj, monkey); // Weak reference, but allow any user
if (65536 == iResult)
iResult = (UInt32)rot.Register(ROTFLAGS_REGISTRATIONKEEPSALIVE, obj, monkey);
cookie = (HRESULT)iResult;
}
public void RemoveFromROT()
{
if (cookie != 0)
{
try
{
// Get the running object table and revoke the cookie
rot.Revoke((int)cookie);
cookie = 0;
}
finally
{
if (rot != null) while (Marshal.ReleaseComObject(rot) > 0) ;
}
}
}
[DllImport("ole32.dll", ExactSpelling = true)]
private static extern int GetRunningObjectTable([MarshalAs(UnmanagedType.U4)] int reserved, out IRunningObjectTable pprot);
[DllImport("ole32.dll", CharSet = CharSet.Unicode, ExactSpelling = true)]
private static extern int CreateClassMoniker([In] ref Guid g, [Out] out IMoniker ppmk);
#region IDisposable Members
public void Dispose()
{
if (null != monkey)
Marshal.ReleaseComObject(monkey);
rot.Revoke((int)cookie);
Marshal.ReleaseComObject(rot);
}
#endregion
}
[ComVisible(true)]
[Guid("331F1768-05A9-4ddd-B86E-DAE34DDC998A")]
[ClassInterface(ClassInterfaceType.None)]
public class Autoplay : IQueryCancelAutoPlay, IDisposable
{
private RunningObjectTableEntry rotEntry;
public Autoplay()
{
rotEntry = new RunningObjectTableEntry(this);
}
public void RemoveFromROT()
{
this.rotEntry?.RemoveFromROT();
}
#region IQueryCancelAutoPlay Members
public int AllowAutoPlay(string pszPath, AutorunContent dwContentType, string pszLabel, int dwSerialNumber)
{
String msgUser = $"AllowAutoPlay: Path={pszPath}, ContentType={dwContentType.ToString()}, Label={pszLabel}, SerialNumber={dwSerialNumber.ToString()}";
System.Diagnostics.Debug.WriteLine(msgUser);
MessageBox.Show(msgUser);
}
#endregion
#region IDisposable Members
public void Dispose()
{
rotEntry.Dispose();
}
#endregion
}
The cookie on the second call is fine, consistent, but fine at 131073 or 0x00020001.
I used the following articles: Prevent Autoplay, 65536 error, and CodeProject.
Neither a breakpoint or the message box shows.
I am running on Windows 10 using Visual Studio 2017.
Thoughts?
My first answer is the technical answer, which answers the specific question, however the first answer does NOT address the problem.
I struggled and finally found a real solution, which I wanted to share.
My test application with the solution DOES receive the QueryCancelAutoPlay message, however my real application does NOT. I used the Windows SDK Inspect utility, added the WndProc() to every form and nothing.
I also do not like the only the active window gets QueryCancelAutoPlay message. If the user happens to shift to another application momentarily, then this talked method will not work.
I once started down the path of the answer mentioned here and for whatever reason abandoned it.
I now have 2 ComboBox controls in the setup area. One holds the Windows default, while the other is for the application. I then set the application upon launch to the application version, and upon application exit I reset to the Windows default option, which I stored in the ComboBox.
Works great.
private const String RegKey_UserChosen_StorageOnArrival = @"Software\Microsoft\Windows\CurrentVersion\Explorer\AutoplayHandlers\UserChosenExecuteHandlers\StorageOnArrival";
private const String RegKey_Event_StorageOnArrival = @"Software\Microsoft\Windows\CurrentVersion\Explorer\AutoplayHandlers\EventHandlersDefaultSelection\StorageOnArrival";
private const String RegValue_NoAction = @"MSTakeNoAction";
private const String RegValue_OpenFolder = @"MSOpenFolder";
public static Boolean SetExplorerAutoplay(String regValue)
{
try
{
// Open first key needed.
using (RegistryKey oKey = Registry.CurrentUser.OpenSubKey(ExplorerAutoplay.RegKey_UserChosen_StorageOnArrival, true))
{
// Set the default value. To set the default value do not use "(Default)", but rather leave blank.
oKey.SetValue(String.Empty, regValue);
}
// Open second key needed.
using (RegistryKey oKey = Registry.CurrentUser.OpenSubKey(ExplorerAutoplay.RegKey_Event_StorageOnArrival, true))
{
// Set the default value. To set the default value do not use "(Default)", but rather leave blank.
oKey.SetValue(String.Empty, regValue);
}
return true;
}
catch (Exception)
{
}
return false;
}
public static Boolean GetExplorerAutoplay(out AutoPlayDriveAction action, out String regValue)
{
action = AutoPlayDriveAction.Invalid;
regValue = null;
try
{
// Only one of the keys is necessary, as both are the same.
using (RegistryKey oKey = Registry.CurrentUser.OpenSubKey(ExplorerAutoplay.RegKey_UserChosen_StorageOnArrival, true))
{
// Get the default value.
object oRegValue = oKey.GetValue(String.Empty);
regValue = oRegValue?.ToString();
if (true == regValue.Equals(ExplorerAutoplay.RegValue_NoAction))
action = AutoPlayDriveAction.TakeNoAction;
else if (true == regValue.Equals(ExplorerAutoplay.RegValue_OpenFolder))
action = AutoPlayDriveAction.OpenFolder;
}
return true;
}
catch (Exception)
{
}
return false;
}
public enum AutoPlayDriveAction
{
Invalid,
TakeNoAction,
OpenFolder,
}