Create Custom Search Function

You don't create a "VaultViewOperations" instance.  You use the instance from your local vault reference (e.g. "dashboard.Vault.ViewOperations.AddTemporarySearchViewEx..").

Thanks Craig Hawker, i can create the temporary search view now, but when i call shellFrame.NavigateToFolder, it show "Folder  'M:\Sample Vault\Test View' no longer exists" error msg

Show your code maybe? 

Here is the view created

var oView = new MFiles.View();
oView.Name = "Test View";
				
//Create the search criteria for the view.
var oSc = new MFiles.SearchCriteria();
oSc.FullTextSearchString = "demo*";
oSc.FullTextSearchFlags = (MFiles.MFFullTextSearchFlags.MFFullTextSearchFlagsStemming |
	MFiles.MFFullTextSearchFlags.MFFullTextSearchFlagsLookInMetaData |
	MFiles.MFFullTextSearchFlags.MFFullTextSearchFlagsLookInFileData |
	MFiles.MFFullTextSearchFlags.MFFullTextSearchFlagsTypeAllWords);
oSc.SearchFlags = MFiles.MFSearchFlags.MFSearchFlagNone;
oSc.ExpandUI = true;

//Create search conditions for the view: object status is not deleted
var oExpression = new MFiles.Expression();
oExpression.DataStatusValueType = MFiles.MFStatusType.MFStatusTypeDeleted;
oExpression.DataStatusValueDataFunction = MFiles.MFDataFunction.MFDataFunctionNoOp;

var oTypedValue = new MFiles.TypedValue();
oTypedValue.SetValue(MFDataType.MFDatatypeBoolean, false);

var oDeletedEx = new MFiles.SearchConditionEx();
oDeletedEx.SearchCondition.Set(oExpression, MFiles.MFConditionType.MFConditionTypeEqual, oTypedValue);
oDeletedEx.Enabled = true;
oDeletedEx.Ignored = false;
oDeletedEx.SpecialNULL = false;

oSc.AdditionalConditions.Add(-1, oDeletedEx);

oView = dashboard.Vault.ViewOperations.AddTemporarySearchViewEx(oView, oSc, true);
shellFrame.ShowMessage("View created: " + oView.ID + " " + oView.Name + " " + oView.GUID + " " + oView.Visible);

Here is navigate to the view, and the <param> is from created view ID

var fd = new MFiles.FolderDef();
fd.SetView(param);
var fds = new MFiles.FolderDefs();
fds.Add(0,fd);
shellFrame.NavigateToFolder(fds);

At least in the desktop client temporary searches are within the "latest searches" built-in view, so my guess is that you need to ensure that your folderdefs replicate that:

var fd1 = new MFiles.FolderDef();
fd1.SetView(MFBuiltInView.MFBuiltInViewLatestSearches); // May need to pass 11 instead
var fd = new MFiles.FolderDef();
fd.SetView(param);
var fds = new MFiles.FolderDefs();
fds.Add(0,fd1); // First "latest searches"
fds.Add(0,fd); // Then the temporary view itself.
shellFrame.NavigateToFolder(fds);