Access the Windows 7 Boot Configuration Data using

I need to be able to access the identifier GUID of the current running installation of Windows from the Boot Configuration Data Store using c#. It can be returned from the command line running:

bcdedit /enum {current} /v

The problem I have is that in c# if I try to directly run this command (even though the program is running as Administrator) I'm told that bcdedit does not exist. I'm using:

ProcessStartInfo procStartInfo = new ProcessStartInfo("bcdedit.exe", "/enum {current} /v");

The other thing that I have researched is using WMI but the only reference I have to doing so is http://msdn.microsoft.com/en-us/library/windows/desktop/aa362673(v=vs.85).aspx which isn't very helpful.

The best solution would be if I don't have to use bcdedit but instead could use native WMI classes. How would I find the current Windows Boot Loader identifier using C#?

回答1:

There seem to be many problems accessing bcdedit.exe directly but I was able to figure out how to use WMI in C# to access the BcdStore:

ConnectionOptions connectionOptions = new ConnectionOptions();
connectionOptions.Impersonation = ImpersonationLevel.Impersonate;
connectionOptions.EnablePrivileges = true;

// The ManagementScope is used to access the WMI info as Administrator
ManagementScope managementScope = new ManagementScope(@"root\WMI", connectionOptions);

// {9dea862c-5cdd-4e70-acc1-f32b344d4795} is the GUID of the System BcdStore
ManagementObject privateLateBoundObject = new ManagementObject(managementScope, new ManagementPath("root\\WMI:BcdObject.Id=\"{9dea862c-5cdd-4e70-acc1-f32b344d4795}\",StoreFilePath=\"\""), null);

ManagementBaseObject inParams = null;
inParams = privateLateBoundObject.GetMethodParameters("GetElement");

// 0x24000001 is a BCD constant: BcdBootMgrObjectList_DisplayOrder
inParams["Type"] = ((UInt32)0x24000001);
ManagementBaseObject outParams = privateLateBoundObject.InvokeMethod("GetElement", inParams, null);
ManagementBaseObject mboOut = ((ManagementBaseObject)(outParams.Properties["Element"].Value));

string[] osIdList = (string[]) mboOut.GetPropertyValue("Ids");

// Each osGuid is the GUID of one Boot Manager in the BcdStore
foreach (string osGuid in osIdList)
{
    ManagementObject currentManObj = new ManagementObject(managementScope, new ManagementPath("root\\WMI:BcdObject.Id=\"" + osGuid + "\",StoreFilePath=\"\""), null);
            MessageBox.Show("" + currentManObj.GetPropertyValue("Id"));
}

This gets the GUID of every Windows Boot Manager in the BcdStore and shows them in a MessageBox. It should be noted that you must have the right ConnectionOptions and that this program must be run as Administrator.

Thanks to Ross Johnston for his project at: http://www.codeproject.com/script/Articles/ViewDownloads.aspx?aid=18233 to find the BCD constants and to Tran Dinh Hop for his project at: http://www.codeproject.com/script/Articles/ViewDownloads.aspx?aid=19208 which has all of the C# code to work with the BcdStore (except for the aforementioned constants).

Update:

Using:

ManagementObject privateLateBoundObject = new ManagementObject(managementScope, new ManagementPath("root\\WMI:BcdObject.Id=\"{fa926493-6f1c-4193-a414-58f0b2456d1e}\",StoreFilePath=\"\""), null);

will obtain the BcdObject for the current, running Windows Boot Manager. If you then call:

currentManObj.GetPropertyValue("Id")

you will get the GUID of the current, running Windows Boot Manager which is different from "{fa926493-6f1c-4193-a414-58f0b2456d1e}" which is a link to the current Boot Manager.

Thanks to The Microsoft Scripting Guys and their project at: http://technet.microsoft.com/en-us/magazine/2008.07.heyscriptingguy.aspx?pr=blog for having that GUID constant that links to the current Boot Manager.

回答2:

Note that there is only a 64-bit bcdedit.exe in %systemroot%\system32. If your app is 32-bit, it will not be able to launch the 64-bit bcdedit because the WOW64 layer remaps the system32\ directory to syswow64. It's definitely best to use the WMI interface.