Insert Multiple records RIA services - silverlight-4.0

I have a service class to hold the calls to the RIA service.
I have the following method to save multiple records, on the first step I should get the famous MaxId from the table and increment it in the foreach to add the objects.
public bool SaveRecs(ObservableCollection<Acc> accList)
{
int i = 0;
invokeOperation = Context.GetMaxAcc();
invokeOperation.Completed +=
(s, a) =>
{
foreach (Acc item in accList)
{
//if (CheckAcc(item.name, item.id)) continue;
item.id = invokeOperation.Value + i;
Context.Accs.Add(item);
i++;
}
};
return Commit();
}
The problem is that when the method is called first time, it do nothing and second time it works, the strange is that it may give an error of duplicate.
when I debug the code the id was ZERO
Is this the correct way of doing it?
thanks

My mistake, I should move the commit after the foreach.

Related

Update context in SQL Server from ASP.NET Core 2.2

_context.Update(v) ;
_context.SaveChanges();
When I use this code then SQL Server adds a new record instead of updating the
current context
[HttpPost]
public IActionResult PageVote(List<string> Sar)
{
string name_voter = ViewBag.getValue = TempData["Namevalue"];
int count = 0;
foreach (var item in Sar)
{
count = count + 1;
}
if (count == 6)
{
Vote v = new Vote()
{
VoteSarparast1 = Sar[0],
VoteSarparast2 = Sar[1],
VoteSarparast3 = Sar[2],
VoteSarparast4 = Sar[3],
VoteSarparast5 = Sar[4],
VoteSarparast6 = Sar[5],
};
var voter = _context.Votes.FirstOrDefault(u => u.Voter == name_voter && u.IsVoted == true);
if (voter == null)
{
v.IsVoted = true;
v.Voter = name_voter;
_context.Add(v);
_context.SaveChanges();
ViewBag.Greeting = "رای شما با موفقیت ثبت شد";
return RedirectToAction(nameof(end));
}
v.IsVoted = true;
v.Voter = name_voter;
_context.Update(v);
_context.SaveChanges();
return RedirectToAction(nameof(end));
}
else
{
return View(_context.Applicants.ToList());
}
}
You need to tell the DbContext about your entity. If you do var vote = new Vote() vote has no Id. The DbContext see this and thinks you want to Add a new entity, so it simply does that. The DbContext tracks all the entities that you load from it, but since this is just a new instance, it has no idea about it.
To actually perform an update, you have two options:
1 - Load the Vote from the database in some way; If you get an Id, use that to find it.
// Loads the current vote by its id (or whatever other field..)
var existingVote = context.Votes.Single(p => p.Id == id_from_param);
// Perform the changes you want..
existingVote.SomeField = "NewValue";
// Then call save normally.
context.SaveChanges();
2 - Or if you don't want to load it from Db, you have to manually tell the DbContext what to do:
// create a new "vote"...
var vote = new Vote
{
// Since it's an update, you must have the Id somehow.. so you must set it manually
Id = id_from_param,
// do the changes you want. Be careful, because this can cause data loss!
SomeField = "NewValue"
};
// This is you telling the DbContext: Hey, I control this entity.
// I know it exists in the DB and it's modified
context.Entry(vote).State = EntityState.Modified;
// Then call save normally.
context.SaveChanges();
Either of those two approaches should fix your issue, but I suggest you read a little bit more about how Entity Framework works. This is crucial for the success (and performance) of your apps. Especially option 2 above can cause many many issues. There's a reason why the DbContext keep track of entities, so you don't have to. It's very complicated and things can go south fast.
Some links for you:
ChangeTracker in Entity Framework Core
Working with Disconnected Entity Graph in Entity Framework Core

Deleting many managed objects selectd by fragment name

I want to delete many managed objects, selected by fragment type. There are more then 2000 elements in it. Unfortunately I can not delete all with one function call. I have to call this function many times until I have deleted all. How can I delete a list of managed objects in a sufficient way? Not defining page size did not help...
This is my current function:
InventoryFilter filter = new InventoryFilter();
filter.byFragmentType("xy_fragment");
ManagedObjectCollection moc = inventoryApi.getManagedObjectsByFilter(filter);
int count = 0;
// max page size is 2000
for (ManagedObjectRepresentation mo : moc.get(2000).allPages()) {
if (mo.get("c8y_IsBinary") != null) {
binariesApi.deleteFile(mo.getId());
} else {
inventoryApi.delete(mo.getId());
}
LOG.debug(count + " remove: " + mo.getName() + ", " + mo.getType());
count++;
}
LOG.info("all objectes removed, count:" + count);
By calling moc.get(2000).allPages() you already obtain an iterator that queries following pages on demand as you iterate over it.
The problem you are facing is caused by deleting elements from the same list you are iterating over. You delete element from the first page, but once the second page is queried from the server it does not contain the expected elements anymore because you already deleted the first page. Now all elements are shifted forward by your page size.
You can avoid all of that by making a local copy of all elements you want to delete first:
List<ManagedObjectRepresentation> allObjects = Lists.newArrayList( moc.get(2000).allPages())
for (ManagedObjectRepresentation mo : allObjects) {
//delete here
}
There is no bulk delete allowed on the inventory API so your method of looping through the objects is the correct approach.
A bulk delete is already a dangerous tool on the other APIs but on the inventory API it would give you the potential to accidentally delete all your data with just one call (as all data associated with a managedObject is also deleted upon the deletion of the managedObject).
That is why it is not available.
I solved the problem by calling the method until no elements can be found any more. It is not nice but I have no other idea.
public synchronized void removeManagedObjects(String deviceTypeKey) {
int count = 0;
do {
count = deleteManagedObjectes(deviceTypeKey);
}while(count > 0);
}
private int deleteManagedObjectes(String deviceTypeKey) {
InventoryFilter filter = new InventoryFilter();
filter.byFragmentType("xy_fragment");
ManagedObjectCollection moc = inventoryApi.getManagedObjectsByFilter(filter);
int count = 0;
if(moc == null) {
LOG.info("ManagedObjectCollection are NULL");
return count;
}
for (ManagedObjectRepresentation mo : moc.get(2000).allPages()) {
if (mo.get("c8y_IsBinary") != null) {
binariesApi.deleteFile(mo.getId());
} else {
inventoryApi.delete(mo.getId());
}
LOG.debug(count + " remove: " + mo.getName() + ", " + mo.getType());
count++;
}
LOG.info("all objectes removed, count:" + count);
return count;
}

Dapper.Net and the DataReader

I have a very strange error with dapper:
there is already an open DataReader associated with this Command
which must be closed first
But I don't use DataReader! I just call select query on my server application and take first result:
//How I run query:
public static T SelectVersion(IDbTransaction transaction = null)
{
return DbHelper.DataBase.Connection.Query<T>("SELECT * FROM [VersionLog] WHERE [Version] = (SELECT MAX([Version]) FROM [VersionLog])", null, transaction, commandTimeout: DbHelper.CommandTimeout).FirstOrDefault();
}
//And how I call this method:
public Response Upload(CommitRequest message) //It is calling on server from client
{
//Prepearing data from CommitRequest
using (var tr = DbHelper.DataBase.Connection.BeginTransaction(IsolationLevel.Serializable))
{
int v = SelectQueries<VersionLog>.SelectVersion(tr) != null ? SelectQueries<VersionLog>.SelectVersion(tr).Version : 0; //Call my query here
int newVersion = v + 1; //update version
//Saving changes from CommitRequest to db
//Updated version saving to base too, maybe it is problem?
return new Response
{
Message = String.Empty,
ServerBaseVersion = versionLog.Version,
};
}
}
}
And most sadly that this exception appearing in random time, I think what problem in concurrent access to server from two clients.
Please help.
This some times happens if the model and database schema are not matching and an exception is being raised inside Dapper.
If you really want to get into this, best way is to include dapper source in your project and debug.

A misbehaving WCF service asynch call

Okay, I have a WCF service which is going to be acting as a way to access my SQL database. That part has become largely irrelevant to this question, since for some reason my WCF service crashes. Or, at least, it causes my client Silverlight application to crash. This is why I come here to ask you guys about it.
So here's the code. Bear in mind that it is called asynchronously from my Silverlight client. When it is done, the string that is returned from this method is put on the screen for the client.
public string AddClients(IEnumerable<Client> newClients)
{
int nAdded = 0;
int nelse = 0;
string str = "";
List<Client> newClientsList = newClients.ToList();
List<Client> existingClients = dc.Clients.ToList();
List<Client> clientsToAdd = new List<Client>();
return newClientsList.Count.ToString();
foreach (Client client in newClientsList)
{
var clt = existingClients.FirstOrDefault(c => c.ClientName == client.ClientName);
if (clt == null)
{
return clt.ClientName;
//str = str + " found: " + clt.ClientName + "\n";
//dc.Clients.(clt);
//existingClients.Add(clt);
// clientsToAdd.Add(clt);
nAdded++;
}
else
{
nelse++;
}
}
if (nAdded > 0)
{
//str = str + " more than one nAdded";
// dc.Clients.InsertAllOnSubmit(clientsToAdd);
// dc.SubmitChanges();
}
return nelse.ToString();
}
You may be able to figure out what's supposed to be happening, but most of it's not happening now due to the fact that it's not working out for me very well.
At the moment, as you can see, there is a return quite early on (before the foreach). With things as they are, that works okay. You press a button in the client, it makes the call, and then returns. So as it is, you get '3' returned as a string (this is the size of newClients, the parameter). That is okay, and at least proves that the service can be connected to, that it returns messages okay, and what not.
If I remove that top most return, this is where it gets interesting (well, problematic). It should either return clt.ClientName, in the if (clt==null) condition, or it should return nelse.ToString() which is right at the end.
What do I actually get? Nothing. The method for the completion never seems to get called (the message box it shows never appears).
I've commented most of the stuff out. Surely it has to get to one of these conditions! Have I missed something really obvious here? I really have been attempting to debug this for ages, but nothing! Can someone see something obvious that I can't see?
For the record, 'dc' is the data context, and dc.Clients is a list of Client entities.
I could be missing something, but won't this throw a NullReferenceException? That has to be at least part of your problem.
if (clt == null)
{
return clt.ClientName;
...
I dont understand why you are trying to return the name of the first newly found client from the list you received. Why not just return an integer with total count of newly found clients that you are inserting in the database.
Try:
public string AddClients(IEnumerable<Client> newClients)
{
string str = "";
List<Client> newClientsList = newClients.ToList();
//to save processor and network
List<string> existingClients = dc.Clients.Select(x => x.ClientName).ToList();
List<Client> clientsToAdd = (from nc in newClientsList
join ec in existingClients on nc.ClientName equals ec into nec
from ec in nec.DefaultIfEmpty()
where ec == null
select nc).ToList();
if (clientsToAdd.Count > 0)
{
dc.Clients.InsertAllOnSubmit(clientsToAdd);
foreach (Client c in clientsToAdd)
str += "found: " + c.ClientName + "\n";
return str;
}
return "0 new clients found";
}
easier, simpler, cleaner.

How do I mock this value using Rhino Mocks

Here is the method I'm trying to test:
public override void CalculateReductionOnYield()
{
log.LogEnter();
if (illus.RpFundStreams.Count <= 0)
{
throw new InvalidDataException("No regular premium fund streams which are required in order to calculate reduction on yield");
}
// Add the individual ReductionOnYield classes to the collection.)
foreach (RegularPremiumFundStream fs in illus.RpFundStreams)
{
foreach (int i in ReductionOnYieldMonths)
{
ReductionOnYield roy = new ReductionOnYield(i);
roy.FundStream = fs;
ReductionsOnYield.Add(roy);
}
foreach (ReductionOnYield redOnYield in ReductionsOnYield)
{
if (redOnYield.Month == 0 || illus.RegularPremiumInPlanCurrency == 0M)
{
redOnYield.Reduction = 0M;
}
else
{
double[] regPremiums = new double[redOnYield.Month + 1];
for (int i = 1; i <= redOnYield.Month; i++)
{
regPremiums[i - 1] = Convert.ToDouble(-1*redOnYield.FundStream.FundStreamMonths[i].ValRegularPremium);
}
regPremiums[redOnYield.Month] = Convert.ToDouble(redOnYield.FundStream.GetFundStreamValue(redOnYield.Month));
redOnYield.Reduction = Convert.ToDecimal(Math.Pow((1 + Financial.IRR(ref regPremiums, 0.001D)), 12) - 1);
}
}
}
How do I mock all the required classes to test the value of redOnYield.Reduction to make sure that it working properly?
e.g. how do I mock redOnYield.FundStream.GetFundStreamValue(redOnYield.Month) and redOnYield.FundStream.FundStreamMonths[i].ValRegularPremium ?
Is this a valid test? Or am I going about this the wrong way?
without more info on your objects its hard to say, but you want something like:
var fundStream = MockRepository.GenerateStub<TFundStream>();
fundStream.Stub(f => f.GetFundStreamValue(60)).Return(220000M);
var redOnYeild = MockRepository.GenerateStub<TRedOnYeild>();
redOnYeild.Stub(r => r.FundStream).Return(fundStream);
redOnYield is an object returned from iterating ReductionsOnYield. I don't see where this is coming from. If we assume it's a virtual property, then you'll want to create a collection of mock ReductionOnYield objects and stub out ReductionsOnYield to return your mocked collection (or, to make it easier to test, have CalculateReductionOnYield accept an IEnumerable and operate on that collection).
Once you get the ReductionsOnYield issue resolved, Andrew's response of stubbing out the properties will get you where you want to be. Of course, this assumes that FundStream is virtual (so it can be mocked/stubbed) as well as RegularPremiumFundStream's GetFundStreamValue and FundStreamMonths.