Volume Shadow Copies from .NET

        // Administrator Privilege Required for vss operation!!!

    	void vssTest()
    	{
    	    VssWMI vss = new VssWMI();
    	    try
    	    {
    		vss.SetVolume(@"C:\");
    		// copy files with CopyFile API from vss.DeviceName
    	    }
    	    finally
    	    {
    		vss.DelVolume();
    	    }
    	}
 

    public class VssWMI
    {
        public string DeviceName = string.Empty;
        public string Volume = string.Empty;
 
        public string SetVolume(string volume)
        {
            DelVolume();
            shadowId = createShadow(volume);
            DeviceName = getShadowDevice(shadowId);
            Volume = volume;
            return DeviceName;
        }
 
        public void DelVolume()
        {
            if (shadowId != string.Empty) 
                deleteShadow(shadowId);
            shadowId = string.Empty;
            DeviceName = string.Empty;
            Volume = string.Empty;
        }
 
        static string shadowId = string.Empty;
        static string shadowNamespace = @"\\localhost\root\cimv2";
 
        static string createShadow(string volume)
        {
            string res = string.Empty;
            ManagementClass mgmtClass = new ManagementClass(shadowNamespace, "Win32_ShadowCopy", null);
            ManagementBaseObject inParams = mgmtClass.GetMethodParameters("Create");
 
            inParams.SetPropertyValue("Volume", volume);
            inParams.SetPropertyValue("Context", "ClientAccessible");
 
            ManagementBaseObject outParams =
                mgmtClass.InvokeMethod("Create", inParams, null);
 
            res = (string)outParams["ShadowID"];
            
            if (res == string.Empty)
                throw new Exception("Error creating shadow copy!");
 
            return res;
        }
 
        static void deleteShadow(string shadowId)
        {
            ManagementObjectSearcher searcher =
                new ManagementObjectSearcher(shadowNamespace,
                "SELECT * FROM Win32_ShadowCopy where ID = '" + shadowId + "'");
            foreach (ManagementObject queryObj in searcher.Get()) {
                queryObj.Delete();
                break;
            }
        }
 
        static string getShadowDevice(string shadowId)
        {
            string res = string.Empty;
            ManagementObjectSearcher searcher =
                new ManagementObjectSearcher(shadowNamespace,
                "SELECT * FROM Win32_ShadowCopy where ID = '" + shadowId + "'");
            foreach (ManagementObject queryObj in searcher.Get()) {
                res = (string)queryObj["DeviceObject"];
                break;
            }
 
            return res;
        }
 
    }
 

                while (true) {
                    int hr = 0;
                    int x = 0;
                    vssAsync.QueryStatus(out hr, ref x);
                    if (hr == VSS_S_ASYNC_FINISHED) {
                        isSnapOpened = true;
                        break;
                    }
                    if (hr == VSS_S_ASYNC_CANCELLED) {
                        throw new Exception("VSS asynchronous operation was canceled by timeout!");
                    }
                    if (asyncSnapCounter >= 60) {
                        vssAsync.Cancel();
                    }
                    asyncSnapCounter++;
                    Thread.Sleep(500);
                }

        public struct VSSErrHelper
        {
            public long ErrorId;
            public string ErrorMsg;
 
            public VSSErrHelper(long errorId, string errorMsg)
            {
                ErrorId = errorId;
                ErrorMsg = errorMsg;
            }
        }
        public static VSSErrHelper[] VSSErrors =
        {
            new VSSErrHelper(VSS_E_BAD_STATE, "A function call was invalid because of the state of either the\nbackup extensions or the coordinator.  For example calling AddToSnapshot\nset prior to calling StartSnapshotSet."),
            new VSSErrHelper(VSS_E_PROVIDER_ALREADY_REGISTERED, "Calling RegisterProvider"),
            new VSSErrHelper(VSS_E_PROVIDER_NOT_REGISTERED, "Calling UnregisterProvider"),
            new VSSErrHelper(VSS_E_PROVIDER_VETO, "Calling DoSnapshotSet"),
            new VSSErrHelper(VSS_E_PROVIDER_IN_USE, "Calling UnregisterProvider, StartSnapshotSet"),
            new VSSErrHelper(VSS_E_OBJECT_NOT_FOUND, "Calling DeleteSnapshots, Query"),
            new VSSErrHelper(VSS_S_ASYNC_PENDING, "Calling IVssAsync::QueryStatus"),
            new VSSErrHelper(VSS_S_ASYNC_FINISHED, "Calling IVssAsync::QueryStatus"),
            new VSSErrHelper(VSS_S_ASYNC_CANCELLED, "Calling IVssAsync::QueryStatus"),
            new VSSErrHelper(VSS_E_VOLUME_NOT_SUPPORTED, "Calling AddToSnapshotSet"),
            new VSSErrHelper(VSS_E_VOLUME_NOT_SUPPORTED_BY_PROVIDER, "Calling AddToSnapshotSet"),
            new VSSErrHelper(VSS_E_OBJECT_ALREADY_EXISTS, "Calling ExposeCurrentState"),
            new VSSErrHelper(VSS_E_UNEXPECTED_PROVIDER_ERROR, "Calling several methods supported by the providers."),
            new VSSErrHelper(VSS_E_CORRUPT_XML_DOCUMENT, "XML document unexpectedly does not match schema."),
            new VSSErrHelper(VSS_E_CORRUPT_XML_DOCUMENT, "An XML document passes as an argument is not valid, i.e., is either\nnot correctly formed XML or does not match the schema"),
            new VSSErrHelper(VSS_E_MAXIMUM_NUMBER_OF_VOLUMES_REACHED, "We cannot add any more volumes since we passed the maximum limit."),
            new VSSErrHelper(VSS_E_FLUSH_WRITES_TIMEOUT, "VSS couldn't flush I/O writes anymore."),
            new VSSErrHelper(VSS_E_HOLD_WRITES_TIMEOUT, "VSS couldn't hold I/O writes anymore."),
            new VSSErrHelper(VSS_E_UNEXPECTED_WRITER_ERROR, "VSS encountered problems while sending events to writers"),
            new VSSErrHelper(VSS_E_SNAPSHOT_SET_IN_PROGRESS, "StartSnapshotSet was called when another snapshot set in the\nprocess of being created."),
            new VSSErrHelper(VSS_E_MAXIMUM_NUMBER_OF_SNAPSHOTS_REACHED, "AddToSnapshotSet was called on a volume that has already reached\nits maxinum number"),
            new VSSErrHelper(VSS_E_WRITER_INFRASTRUCTURE, "The Writer infrastructure is not operating properly.  Check that the\nEvent Service and the Volume Snapshot Service are started and check for\nerrors associdated with these services in the error log."),
            new VSSErrHelper(VSS_E_WRITER_NOT_RESPONDING, "A writer did not respond to a GetWriterStatus call.  This means that\nthe process containing the writer died or is hung."),
            new VSSErrHelper(VSS_E_WRITER_ALREADY_SUBSCRIBED, "A writer has already sucessfully called the Subscribe function.  It cannot call\nsubscribe multiple times."),
            new VSSErrHelper(VSS_E_UNSUPPORTED_CONTEXT, "Attempt to use an unsupported context."),
            new VSSErrHelper(VSS_E_VOLUME_IN_USE, "Calling ChangeDiffAreaMaximumSize"),
            new VSSErrHelper(VSS_E_MAXIMUM_DIFFAREA_ASSOCIATIONS_REACHED, "Calling AddDiffArea"),
            new VSSErrHelper(VSS_E_INSUFFICIENT_STORAGE, "Calling EndPrepareSnapshots, ChangeDiffAreaMaximumSize"),
            new VSSErrHelper(VSS_E_NO_SNAPSHOTS_IMPORTED, "Calling ImportSnapshots, no volumes were successfully imported"),
            new VSSErrHelper(VSS_S_SOME_SNAPSHOTS_NOT_IMPORTED, "Calling ImportSnapshots, some volumes were not successfully imported")/*,
            new VSSErrHelper(VSS_E_SOME_SNAPSHOTS_NOT_IMPORTED, "Calling ImportSnapshots, some volumes were not successfully imported"),
            new VSSErrHelper(VSS_E_MAXIMUM_NUMBER_OF_REMOTE_MACHINES_REACHED, "While calling AddToSnapshotSet - cannot add shares to snapshot from other machines\nsince we passed the maximum remote machines limit."),
            new VSSErrHelper(VSS_E_REMOTE_SERVER_UNAVAILABLE, "Remote machine that exposes a share to snapshot is not available"),
            new VSSErrHelper(VSS_E_REMOTE_SERVER_UNSUPPORTED, "Remote machine that exposes the share to snapshot runs a VSS version\nthat does not support creation of snapshots for shares"),
            new VSSErrHelper(VSS_E_REVERT_IN_PROGRESS, "A revert is currently in progress for the specified volume.  Another revert\ncannot be initiated until the current revert completes"),
            new VSSErrHelper(VSS_E_REVERT_VOLUME_LOST, "The volume being reverted was lost during revert.")*/
        };
 
        private static Exception getVSSErrMsg(Exception e)
        {
            //Message	"Exception from HRESULT: 0x80000000"	
            int indexOfErrorId = -1;
            long errorId = 0;
            string srcErrMsg = "";
            indexOfErrorId = e.Message.IndexOf("HRESULT:");
            if (indexOfErrorId >= 0) {
                srcErrMsg = e.Message.Substring(indexOfErrorId);
                try {
                    errorId = Convert.ToInt64(e.Message.Substring(indexOfErrorId + 8).Trim(), 16);
                } catch { errorId = 0; }
            }
            if (errorId > 0) {
                foreach (VSSErrHelper dscr in VSSErrors) {
                    if (dscr.ErrorId == errorId)
                        return new Exception("VSS ERROR: " + dscr.ErrorMsg + " (" +
                            srcErrMsg + ")", e);
                }
            }
            return e;
        }