Is there a way of getting the Action, and reading any attributes, during the model binding phase?
The scenario is this:
I've got a default model binder set-up for a certain data-type, but depending on how it's being used (which is controlled via an attribute on the action) I need to ignore a set of data.
I can use the RouteData on the controller context and see the action name, which I can use to go get the data, but wondered if that information is already available.
Additionally, if the action in question is an asynchronous one, they'd be more processing involved in looking it up...
You could walk the stack trace and find the first method that returns an ActionResult and pull the attributes:
StackTrace st = new StackTrace();
for (int i = 0; i < st.FrameCount; i++)
{
StackFrame frame = st.GetFrame(i);
MethodBase mb = frame.GetMethod();
if (mb is MethodInfo)
{
MethodInfo mi = (MethodInfo)mb;
if (typeof(ActionResult).IsAssignableFrom(mi.ReturnType))
{
object[] methodAttributes = mb.GetCustomAttributes(true);
object[] objectAttributes = mb.DeclaringType.GetCustomAttributes(true);
}
}
}
This would only work if you call UpdateModel after the action has been called not when the model is bound before reaching the action method.
Related
Due to a strange behavior in my application, i am forced to reload the designer before calling WorkflowInvoker.Invoke on it.
wd.Flush();
SaveXamlFile(currentXamlPath, wd.Text);
I just flush the content, and write the wd.Text to a file.
//cleanup the previous designer
if (wd != null)
{
wd.ModelChanged -= new EventHandler(Designer_ModelChanged);
}
//designer
wd = new WorkflowDesigner();
designerArea.Child = wd.View;
this.DebuggerService = this.wd.DebugManagerView;
//property grid
propertiesArea.Child = wd.PropertyInspectorView;
//event handler
wd.ModelChanged += new EventHandler(Designer_ModelChanged);
//error service
wd.Context.Services.Publish<IValidationErrorService>(errorService);
wd.Context.Items.Subscribe<Selection>(OnItemSelected);
I then recreate a new instance of the WorkflowDesigner and load the previously saved file.
wd.Load(currentXamlPath);
I call WorkflowInvoker.Invoke and inside my custom activity which derives from CodeActivity i am taking it's name:
OK, fine until now, i have a 1.2 Id there.
I want to update some of the fields of this Activity via its ModelItem in order to display them in the GUI right away.
IEnumerable<ModelItem> activityCollection = currentWorkflow.Find(currentWorkflow.Root, typeof(Activity));
But here comes the issue:
I can't find that my Activity id there. Is now transformed from 1.2 to 2. Why is this happening?
I've tried to send a this reference from my Activity Execute method and searched it by ref but all i get is nulls.
ModelItem temp = activityCollection.FirstOrDefault((m) => (m.GetCurrentValue() == a));
I am sure i am missing something here, but i can't figure out what is it.
I found a workaround on this :
On my custom activities i am adding a Guid property and I override CacheMetadata:
public Guid unique { get; set; }
protected override void CacheMetadata(CodeActivityMetadata metadata)
{
if (unique.ToString() == "00000000-0000-0000-0000-000000000000")
unique = Guid.NewGuid();
}
When i drag the activity on the designer, the unique id is generated. I make sure that this portion of code is called only once.
Why is that?
Because after a call like this,
IEnumerable<ModelItem> activityCollection = currentWorkflow.Find(currentWorkflow.Root, typeof(Activity));
each model in the activity collection contains that property ( unique of type Guid ) with the value of the first assignment made in CacheMetadata. I can't explain this behavior, i've just taken it into consideration.
Who calls again that CacheMetadata ? something like this :
Activity root = ActivityXamlServices.Load(currentXamlPath);
WorkflowInspectionServices.CacheMetadata(root);
And so, the Guid is changed and its utility is gone.
This way, i am able to get the ModelItem for my custom activity and update some of its properties which are immediately displayed in the GUI.
I'm a bit stumped. From what I've read setting the DbContext.AutoDetectChangesEnabled to false should disable change tracking requiring one to call DbContext.DetectChanges in order to identify changes to be sent to the database.
However, it is clear from my logs below that the changes are being registered by dbContexts change tracker, even with the setting set to false.
Am I missing something?
Entity Framework Version: 5.0.0.0
DbContext class
public class ProjectContext : DbContext {
public DbSet<Project> Projects {get;set;}
}
Controller class
private ProjectContext db = new ProjectContext();
public method(){
Project p = new Project("uniqueName");
db.Configuration.AutoDetectChangesEnabled = false;
db.Projects.Add(p);
DebugChangeTracker();
db.SaveChanges();
db.Projects.First().ProjectName = "a differentName!";
DebugChangeTracker();
db.SaveChanges();
}
Logging method
private void DebugChangeTracker()
{
var path = "C:\\mypath\\";
path = path + Util.GetMsSinceEpoch().ToString() + "changeTracker.log";
using (StreamWriter sw = new StreamWriter(path))
{
var changeTracker = db.ChangeTracker;
var entries = changeTracker.Entries();
foreach (var x in entries)
{
var name = x.Entity.ToString();
var state = x.State;
sw.WriteLine("");
sw.WriteLine("***Entity Name: " + name +
"is in a state of " + state);
var currentValues = x.CurrentValues;
sw.WriteLine("***CurrentValues***");
PrintPropertyValues(currentValues,sw);
if (state != EntityState.Added)
{
sw.WriteLine("***Original Values***");
PrintPropertyValues(x.OriginalValues,sw);
}
}
}
}
First log
***Entity Name: Models.Projectis in a state of Added
***CurrentValues***
ProjectId:0
ProjectName:uniqueName
Second Log
***Entity Name: Models.Projectis in a state of Modified
***CurrentValues***
ProjectId:1
ProjectName:uniqueName
***Original Values***
ProjectId:1
ProjectName:a differentName!
Setting AutoDetectChangesEnabled to false doesn't disable change tracking. (That's what the AsNoTracking() extension method would do.) It just disables the automatic call of DetectChanges that would otherwise occur in many DbContext API methods.
But DetectChanges isn't the only method that participates in change tracking. However, if you don't call it manually at the right places where it is needed the tracked entity states are incomplete or wrong leading to incorrectly saved data.
In your case the state Added in the first part of your method is expected, even with AutoDetectChangesEnabled set to false because you only call db.Projects.Add(p). (The line is missing in your code btw, but I guess it's just a copy and paste error.) Calling a method from the DbContext API tracks changes correctly and the states in the tracker will be correct if the state was correct before the call to Add.
Or in other words: Calling an API method doesn't turn a correct state into a wrong state. But: If AutoDetectChangesEnabled is false it also won't turn a wrong state into a correct state which would be the case if AutoDetectChangesEnabled is true.
However, in the second part of your method you are just changing a POCO property value. After this point the change tracker state is wrong (Unchanged) and without a call to DetectChanges (manually or - if AutoDetectChangesEnabled is true - automatically in ChangeTracker.Entries or SaveChanges) it will never be adjusted. The effect is that the changed property value is not saved to the database.
In the last section mentioning the state Unchanged I'm refering to my own test (and also to what I would expect). I don't know and can't reproduce why you have state Modified.
Sorry, if this sounds all a bit confusing. Arthur Vickers can explain it better.
I find automatic change detection and the behaviour when disabling it rather difficult to understand and to master and I usually don't touch the default (AutoDetectChangesEnabled = true) for any tracked changes that are more complex than the simplest things (like bulk adding entities in a loop, etc.).
If someone looking for AutoDetectChangesEnabled in Entity Framework Core you can find it under ChangeTracker insted of Configuration
Usage like:
context.ChangeTracker.AutoDetectChangesEnabled = false;
//Do something here
context.PriceRecords.Add(newPriceRecord);
context.ChangeTracker.AutoDetectChangesEnabled = true;
according to Entity Framework Automatic Detect Changes's Article
they said:
you may get significant performance improvements by turning it off in some cases
look at this example from that article
using (var context = new BloggingContext())
{
try
{
context.Configuration.AutoDetectChangesEnabled = false;
// Make many calls in a loop
foreach (var blog in aLotOfBlogs)
{
context.Blogs.Add(blog);
}
}
finally
{
context.Configuration.AutoDetectChangesEnabled = true;
}
}
This code avoids unnecessary calls to DetectChanges that would have occurred while calling the DbSet.Add and SaveChanges methods.
I need to get the component associated to a Activity at the event system.
I try to get the component ID using:
public void OnActivityInstanceFinishPost(ActivityInstance activityInstance, string finishMessage, string nextActivity, string dynamicAssignee)
{
if (activityInstance.ProcessInstance.ProcessDefinition.Title.Equals("Component Process IESE"))
{
if (activityInstance.ActivityDefinition.Title.Equals("Create or Edit Component"))
{
WFE workflow = tdse.GetWFE();
try
{
Component comp = (Component)activityInstance.ProcessInstance.Item;
XMLReadFilter filter = new XMLReadFilter();
String processHistoryId = activityInstance.ProcessInstance.ID.Replace("131076", "131080");
ProcessHistory hist = (ProcessHistory)tdse.GetObject(activityInstance.ProcessInstance.ID, EnumOpenMode.OpenModeView, Constants.URINULL, filter);
}
catch (Exception e)
{ }
}
}
}
we try different options:
Component comp = (Component)activityInstance.ProcessInstance.Item;
But this solution returns a null.
Then I found in internet the next solution:
XMLReadFilter filter = new XMLReadFilter();
String processHistoryId = activityInstance.ProcessInstance.ID.Replace("131076", "131080");
ProcessHistory hist = (ProcessHistory)tdse.GetObject(activityInstance.ProcessInstance.ID, EnumOpenMode.OpenModeView, Constants.URINULL, filter);
Component comp = hist.Item as Component;
But the ProcessHistory object is null.
How can I determine the component associated to the activityInstance?
Thank you.
After reviewing the functionality needed by Guskermitt, I've shown him a neater way to do what he needs to do. In short, EventSystem is not needed in this case.
His goal is to send an email after a component has been approved, the approach will be the following:
Add to workflow a new automatic activity.
Create a new .NET assembly, in this case a C# class to do what he needs to do.
Register the assembly in the GAC.
Add logic in the new automatic activity in workflow to use the .NET assembly.
2#
[ProgId("WfHelper")]
[ComVisible(true)]
public class Helper
{
public void SendMail(string workItemId)
{
var session = new Session();
.
.
.
4#
dim helper
set helper = CreateObject("WfHelper")
call helper.SendMail(CurrentWorkItem.ID)
set helper = nothing
FinishActivity “Email has been sent"
ActivityInstance has a WorkItems property (inherited from Activity) that contains a reference to your Component.
OnActivityInstanceFinishPost means that your activity is finished. Therefore there is no more work item associated with it. However, you are getting the process instance and the work item associated with that. If you get null there, then it suggests your workflow process is done and the component has moved out of workflow. From looking at your code, it is quite likely that your ProcessInstance is completed (it won't be null, but it won't have any item associated with it).
I suspect that you've read this post http://www.tridiondeveloper.com/autopublishing-on-workflow-finish suggesting to look in the history. Have you looked into the history via the CM GUI, is the history item there? If it isn't, that's why you get null. A workflow process gets moved to history when it is completed. So double check that you are indeed on the last workflow activity before looking at the history.
By looking at your code, the error seems to be that you are trying to get a history object using activityInstance.ProcessInstance.ID. GetObject() should return an item, but your cast to a ProcessHistory should break and then you quietly eat the exception. You need to pass in the History ID, not the ProcessInstance ID as follows:
ProcessHistory hist = (ProcessHistory)tdse.GetObject(processHistoryId, EnumOpenMode.OpenModeView, Constants.URINULL, filter);
I'm having trouble with one of my queries because of EF's change tracking and lazy loading features. The thing is that after I'm getting the result of the query, I'm using AutoMapper to map the domain objects into my business model but it keeps throwing an exception because the context has been disposed.
The ObjectContext instance has been disposed and can no longer be used
for operations that require a connection.
When I look at the resultant collection in the debugger, I see that it is a list of DynamicProxy and not the actual entity. I tried to stop Change Tracking but that did not help. Here's my code:
public List<ContentTypeColumn> GetContentTypeColumns(Int64 contentTypeId)
{
List<ContentTypeColumn> result = new List<ContentTypeColumn>();
using (SCGREDbContext context = new SCGREDbContext())
{
ContentType contentType = context.ContentTypes.Include("Parent").AsNoTracking().FirstOrDefault(x => x.Id.Equals(contentTypeId));
result.AddRange(contentType.ContentTypeColumns.ToList());
while (contentType.Parent != null)
{
result.AddRange(contentType.Parent.ContentTypeColumns.ToList());
contentType = contentType.Parent;
}
}
return result.ToList();
}
Note: If you need to look into my domain model involved in this operation you can refer to this question.
If you need to stop lazy loading and dynamic change tracking you can simply turn it off:
using (SCGREDbContext context = new SCGREDbContext())
{
context.Configuration.ProxyCreationEnabled = false;
...
}
My database has a 'LastModifiedUser' column on every table in which I intend to collect the logged in user from an application who makes a change. I am not talking about the database user so essentially this is just a string on each entity. I would like to find a way to default this for each entity so that other developers don't have to remember to assign it any time they instantiate the entity.
So something like this would occur:
using (EntityContext ctx = new EntityContext())
{
MyEntity foo = new MyEntity();
// Trying to avoid having the following line every time
// a new entity is created/added.
foo.LastModifiedUser = Lookupuser();
ctx.Foos.Addobject(foo);
ctx.SaveChanges();
}
There is a perfect way to accomplish this in EF 4.0 by leveraging ObjectStateManager
First, you need to create a partial class for your ObjectContext and subscribe to
ObjectContext.SavingChanges Event. The best place to subscribe to this event is inside the OnContextCreated Method. This method is called by the context object’s constructor and the constructor overloads which is a partial method with no implementation:
partial void OnContextCreated() {
this.SavingChanges += Context_SavingChanges;
}
Now the actual code that will do the job:
void Context_SavingChanges(object sender, EventArgs e) {
IEnumerable<ObjectStateEntry> objectStateEntries =
from ose
in this.ObjectStateManager.GetObjectStateEntries(EntityState.Added
| EntityState.Modified)
where ose.Entity != null
select ose;
foreach (ObjectStateEntry entry in objectStateEntries) {
ReadOnlyCollection<FieldMetadata> fieldsMetaData = entry.CurrentValues
.DataRecordInfo.FieldMetadata;
FieldMetadata modifiedField = fieldsMetaData
.Where(f => f.FieldType.Name == "LastModifiedUser").FirstOrDefault();
if (modifiedField.FieldType != null) {
string fieldTypeName = modifiedField.FieldType.TypeUsage.EdmType.Name;
if (fieldTypeName == PrimitiveTypeKind.String.ToString()) {
entry.CurrentValues.SetString(modifiedField.Ordinal, Lookupuser());
}
}
}
}
Code Explanation:
This code locates any Added or Modified entries that have a LastModifiedUser property and then updates that property with the value coming from your custom Lookupuser() method.
In the foreach block, the query basically drills into the CurrentValues of each entry. Then, using the Where method, it looks at the names of each FieldMetaData item for that entry, picking up only those whose Name is LastModifiedUser. Next, the if statement verifies that the LastModifiedUser property is a String field; then it updates the field's value.
Another way to hook up this method (instead of subscribing to SavingChanges event) is by overriding the ObjectContext.SaveChanges Method.
By the way, the above code belongs to Julie Lerman from her Programming Entity Framework book.
EDIT for Self Tracking POCO Implementation:
If you have self tracking POCOs then what I would do is that I first change the T4 template to call the OnContextCreated() method. If you look at your ObjectContext.tt file, there is an Initialize() method that is called by all constructors, therefore a good candidate to call our OnContextCreated() method, so all we need to do is to change ObjectContext.tt file like this:
private void Initialize()
{
// Creating proxies requires the use of the ProxyDataContractResolver and
// may allow lazy loading which can expand the loaded graph during serialization.
ContextOptions.ProxyCreationEnabled = false;
ObjectMaterialized += new ObjectMaterializedEventHandler(HandleObjectMaterialized);
// We call our custom method here:
OnContextCreated();
}
And this will cause our OnContextCreated() to be called upon creation of the Context.
Now if you put your POCOs behind the service boundary, then it means that the ModifiedUserName must come with the rest of data from your WCF service consumer. You can either expose this
LastModifiedUser property to them to update or if it stores in another property and you wish to update LastModifiedUser from that property, then you can modify the 2nd code as follows:
foreach (ObjectStateEntry entry in objectStateEntries) {
ReadOnlyCollection fieldsMetaData = entry.CurrentValues
.DataRecordInfo.FieldMetadata;
FieldMetadata sourceField = fieldsMetaData
.Where(f => f.FieldType.Name == "YourPropertyName").FirstOrDefault();
FieldMetadata modifiedField = fieldsMetaData
.Where(f => f.FieldType.Name == "LastModifiedUser").FirstOrDefault();
if (modifiedField.FieldType != null) {
string fieldTypeName = modifiedField.FieldType.TypeUsage.EdmType.Name;
if (fieldTypeName == PrimitiveTypeKind.String.ToString()) {
entry.CurrentValues.SetString(modifiedField.Ordinal,
entry.CurrentValues[sourceField.Ordinal].ToString());
}
}
}
Hope this helps.
There is a nuget package for this now : https://www.nuget.org/packages/TrackerEnabledDbContext
Github: https://github.com/bilal-fazlani/tracker-enabled-dbcontext