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C# - Retrieve data from persistence storage and save it to the view model

Hello I have a controller method that I want to return the view model of that looks like this
This is what it would look like if it was hard-coded
public ActionResult SpecialOrderSummary(int? id)
{
// Retrieve data from persistence storage and save it to the view model.
// But here I am just faking it.
var vm = new ItemViewModel
{
ItemId = 123,
ItemName = "Fake Item",
Parts = new List<ItemPartViewModel>
{
new ItemPartViewModel
{
PartId = 1,
PartName = "Part 1"
},
new ItemPartViewModel
{
PartId = 2,
PartName = "Part 2"
}
}
};
return View(vm);
}
But I obviously don't want it hard coded. So this is what I was trying to do instead to achieve my goal
public ActionResult SpecialOrderSummary(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
JobOrder jobOrder = db.JobOrders.Find(id);
if (jobOrder == null)
{
return HttpNotFound();
}
ViewBag.JobOrderID = jobOrder.ID;
ItemInstance ii = db.ItemInstances.Where(x => x.serialNumber == jobOrder.serialNumber).FirstOrDefault();
Item item = db.Items.Find(ii.ItemID);
var vm = new ItemViewModel
{
ItemId = item.ItemID,
ItemName = item.Name,
Parts = new List<ItemPartViewModel>
{
foreach(ItemHasParts ihp in item.IHP)
{
Part part = db.Parts.Find(ihp.PartID);
new ItemPartViewModel
{
PartId = part.ID,
PartName = part.Name
};
}
}
};
return View(vm);
}
But that doesn't work. As it doesn't seem to recognize the closing }
of the opening "Parts" and the opening "vm" bracket as it skips both. Why is this?

Hmmm I thought I answered this question before: https://stackoverflow.com/a/62782124/2410655. Basically you can't have a for loop like that in the middle of the view model.
I would like to add 2 more things to it.
1. Id?
If the special order summary expects an ID, don't declare it as optional. If you do so, you have to add more logic to check whether there is an ID or not.
If the order summary expects an ID, just declare it as int id. And if the client doesn't provide it, let the MVC framework handle the error. Now depending on your setup, your MVC might throw a 404, or 500, or a user-friendly page. It's up to you, the developer, to set it up.
2. Be careful on NullReference Exception
In your code example, I see you used FirstOrDefault() on the item instance. That will bite you if it comes back as NULL and you call db.Items.Find(ii.ItemID)...
So based on your example, I would change the code to:
public ActionResult SpecialOrderSummary(int id)
{
JObOrder jobOrder = db.JobOrders.Find(id);
if (jobOrder == null)
{
return HttpNotFound();
}
ItemInstance itemInstance = db.ItemInstances
.Where(x => x.serialNumber == jobOrder.serialNumber)
.FirstOrDefault();
Item item = null;
if (itemInstance != null)
{
item = db.Items.Find(itemInstance.ItemID);
}
var vm = new JobOrderSummaryViewModel
{
JobOrderId = jobOrder.ID,
Parts = new List<ItemPartViewModel>();
};
if (item != null)
{
vm.ItemId = item.ItemId;
vm.ItemName = item.ItemName;
foreach(ItemHasParts ihp in item.IHP)
{
// Does Part and Item have many-to-many relationships?
// If so, you might be able to get the part by
// ihp.Part instead of looking it up using the ID.
// Again, it depends on your setup.
Part part = db.Parts.Find(ihp.PartID);
if (part != null)
{
vm.Parts.Add(new ItemPartViewModel
{
PartId = part.ID,
PartName = part.Name
});
}
}
}
return View(vm);
}
Note:
You have additional calls back to the database inside the loop (db.Parts.Find(ihp.PartID);). That will cause performance issue if you have huge data. Is there any way you can fetch all your data you needed once at the beginning?

Trying to Add to Database: Collection was modified; enumeration operation may not execute?

Below is my controller That I am calling from a href button and passing an id. The href button is a duplicate button which is meant to create a copy of the selected module and add it to the database and then return it.
public ActionResult dupe(int? id)
{
if (id == null)
{
return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
}
MODULE Modules = db.MODULE.Find(id);
if (Modules == null)
{
return HttpNotFound();
}
else
{
MODULE newMOd = new MODULE();
newMOd.APPLY__FINISH = Modules.APPLY__FINISH;
newMOd.CREATED_BY = Modules.CREATED_BY;
newMOd.CREATED_DATE = Modules.CREATED_DATE;
newMOd.MODULE_DESC = "Duplicate-"+Modules.MODULE_DESC;
newMOd.MODULE_TYPE = Modules.MODULE_TYPE;
newMOd.MODULE_TYPE1 = Modules.MODULE_TYPE1;
newMOd.PRODUCT_LINE = Modules.PRODUCT_LINE;
newMOd.MODULE_NAME = "Duplicate-" + Modules.MODULE_NAME;
foreach (MODULE_PARTS mp in Modules.MODULE_PARTS)
{
newMOd.MODULE_PARTS.Add(mp);
}
foreach (MODULE_OPTION mo in Modules.MODULE_OPTION)
{
MODULE_OPTION m = new MODULE_OPTION();
m.OPTION_NAME = mo.OPTION_NAME;
m.OPTION_TYPE = mo.OPTION_TYPE;
m.PRODUCT_LINE = mo.PRODUCT_LINE;
m.ADDED_BY = mo.ADDED_BY;
m.ADDED_ON = mo.ADDED_ON;
m.DEFAULT_FACTOR = mo.DEFAULT_FACTOR;
foreach (OPTION_PARTS op in mo.OPTION_PARTS)
{
m.OPTION_PARTS.Add(op);
}
newMOd.MODULE_OPTION.Add(mo);
}
newMOd.MODULE_PARTS = Modules.MODULE_PARTS;
newMOd.MODULE_OPTION = Modules.MODULE_OPTION;
db.MODULE.Add(newMOd);
db.SaveChanges();
}
return View(Modules);
}
This is my controller method, and when I try to add this module to database I get collection modified error. I'm not sure how or where?
enter image description here

The exception message in this case is quite clear... you cannot modify a member of a collection you are currently iterating over. It's that simple.

asp.net return same view but delete url?

I have a project where I report time on diffrent projects, and I am working on so I can delete a report incase I do it wrong, which is working decent.
When I go to the summery page of all my reports it lists all the dates, I click the date and it sends it to the TimeReport view like this:
http://localhost:9061/Reports/TimeReport/b604a74a-2034-4916-9534-57788db1e8e2
And than it checks if the ReportId has a value like this:
#if (Model.ReportId.HasValue)
{
<button type="button" class="btn btn-danger" data-toggle="modal" data-target="#basic">Ta bort!</button>
}
And if it exists a Remove button will appear, I click the remove button and it will remove the report. but the URL is still the same, so if I refresh the site my application will crash because it that ID no longer exists in the database.
if (form != null && form.AllKeys.Contains("delete"))
{
new DatabaseLayer().DeleteTimeReport(Guid.Parse(form["ReportId"]));
LoadDefaultSettings(projectData);
ViewData.Model = projectData;
ViewData["deleted"] = true;
return View();
}
This is the model that check if if the GUID exists.
public void SaveToDatabase(Guid consultantId)
{
using (DatabaseLayer db = new DatabaseLayer())
{
//Time report exists, delete it.
if (ReportId.HasValue)
{
db.DeleteTimeReport(ReportId.Value);
}
//Time report does not exist, create a new one.
else
{
ReportId = Guid.NewGuid();
}
Report report = new Report
{
FK_ConsultantID = consultantId,
FK_UserID = Constants.UserTreetop,
Date = Date,
TimeReportID = ReportId.Value
};
TimeReportData reportData = new TimeReportData
{
Absent = 0,
Description = "",
StartHour = Times.StartHour,
StartMinute = Times.StartMinute,
EndHour = Times.EndHour,
EndMinute = Times.EndMinute,
BreakHour = Times.BreakHour,
BreakMinute = Times.BreakMinute,
FK_TimeReportID = ReportId.Value,
TimeReportDataID = Guid.NewGuid()
};
TimeReportProject[] reportProjects = new TimeReportProject[Projects.Count];
for (int i = 0; i < Projects.Count; i++)
{
reportProjects[i] = new TimeReportProject
{
Description = Projects[i].Description,
FK_ProjectID = Projects[i].ProjectId,
FK_TimeReportID = ReportId.Value,
Hours = Projects[i].Hours.GetValueOrDefault(), //Projects[i].Hours.Value,
HourRate = db.GetProjectHourRate(Projects[i].ProjectId, Date, Projects[i].Hours.GetValueOrDefault()),
TimeReportProjectID = Guid.NewGuid()
};
}
db.InsertTimeReport(report, reportData, reportProjects);
}
}
And as it exists it does this
public void DeleteTimeReport(Guid timeReportId)
{
db.ExecuteStoreCommand(
#" DELETE FROM [Salesweb].[dbo].[TimeReportProject] WHERE FK_TimeReportID = #id;
DELETE FROM [Salesweb].[dbo].[TimeReportData] WHERE FK_TimeReportID = #id;
DELETE FROM [Salesweb].[dbo].[TimeReport] WHERE TimeReportID = #id;"
, new SqlParameter("#id", timeReportId));
db.SaveChanges();
}
This is the view when I pass in the guid I Want to delete as the guid has a value the remove button will appear.
But as I delete the project it will return to the same view. Like we can see the tabs is not showing up, so if I want the to show again I have to go to another view, and than back to the same view. And if I refresh it will crash due the guid dosen't exist in the DB.
And here is the whole controller, it's a bit messy right now.
public ActionResult TimeReport(FormCollection form, Guid? id)
{
ViewDataDictionary vd = new ViewDataDictionary
{
["projects"] = new DatabaseLayer().GetConsultantProjects(Constants.CurrentUser(User.Identity.Name)),
["id"] = 1,
["showDescription"] = true
};
ViewData["vd"] = vd;
NewTimeReportModel projectData = new NewTimeReportModel();
if (form != null && form.AllKeys.Contains("delete"))
{
new DatabaseLayer().DeleteTimeReport(Guid.Parse(form["ReportId"]));
LoadDefaultSettings(projectData);
ViewData.Model = projectData;
ViewData["deleted"] = true;
return RedirectToAction("Index");
}
if (id.HasValue && (form == null || form.AllKeys.Length == 0))
{
using (DatabaseLayer db = new DatabaseLayer())
{
var timeReport = db.GetTimeReport(id.Value);
projectData = new NewTimeReportModel(timeReport);
if (projectData.Projects.Count == 1)
projectData.Projects[0].Hours = null;
}
}
else if (form == null || form.AllKeys.Length == 0)
{
LoadDefaultSettings(projectData);
}
else
{
//Get's all the dates from the view and formates them to look like yy-mm-dd so we can parse it to a datetime.
string[] dates = FormateDate(form["date"]);
//Loops over all the dates and saves the dates to the database.
projectData = ReportDates(form, projectData, dates);
//Loads default settings if all dates been reported.
LoadDefaultSettings(projectData);
}
//Get's and lists all the missing days
ListAllMssingDays();
ViewData.Model = projectData;
return View();
}

Recommended thing to do in such cases is run redirect to some default URL, like the summary page. Guessing that you have Summary action, that should be something like:
if (form != null && form.AllKeys.Contains("delete"))
{
new DatabaseLayer().DeleteTimeReport(Guid.Parse(form["ReportId"]));
return RedirectToAction("Summary", "Reports");
}
Note that this will do a client-side redirect, so to say - this will do a response with code 302 and new URL /Reports/Summary. This is usually a desired behavior though.

The exception you're getting is because your code assumes the item you're deleting will exist.
Change
return db.TimeReports.Where(x => x.TimeReportID == timeReportId).Single();
To
return db.TimeReports.Where(x => x.TimeReportID == timeReportId).SingleOrDefault();
Which will return null if your Where clause returns 0 items.
Then wherever in your code you're calling GetTimeReport() you need to check for and handle null.

Create an Array from SQL Query Results

I have the following function that searches a database for entries where a column called "description" have the same value. Right now it just returns the first value it finds or a default value is there isn't one.
public static NewCode GetAltCode(int altCodeVer, string descrip)
{
var sql = #"select Code, Description, VersionID from Code.CodeLookup where versionid=#vers and description=#description";
return ObjectFactory.GetInstance<IDatabaseFactory>().Query<NewCode>(sql, new { vers = altCodeVer, description = descrip, }).FirstOrDefault();
}
I have this if statement to check and make sure the result isn't null, and if it is, to say that the "code isn't found"
[Authorize(parentAction: "Edit")]
public ActionResult Lookup(string Code, int? VersionId = null)
{
var Info = VisitViews.GetDescriptionByVersionId(Code, VersionId.HasValue ? VersionId.Value : 9);
var description = string.Empty;
// CHECK FOR NULL
if (Info != null)
{
description = Info.Description;
if (VersionId == 9)
{
var altInfo = VisitViews.GetAltCode(10, description);
}
if (VersionId == 10)
{
var altInfo = VisitViews.GetAltCode(9, description);
}
}
else
description = "CODE NOT FOUND";
return Json(new { Description = description });
}
My question is, instead of doing FirstOrDefault, is there a way to store the results in an array (or even to store them in a list and call ToArray on the list)? I'm trying to get all of the codes received during the sql search instead of just one so that another function I am working on can traverse the array and place the items where they need to be in a UI.

For future reference of this post, here is the answer:
Change the return type to NewCode[] and replace .FirstOrDefault() with .ToArray()
public static NewCode[] GetAltCode(int altCodeVer, string descrip)
{
var sql = #"select Code, Description, VersionID from Code.CodeLookup where versionid=#vers and description=#description";
return ObjectFactory.GetInstance<IDatabaseFactory>().Query<NewCode>(sql, new { vers = altCodeVer, description = descrip, }).ToArray();
}

Persisting data in ASP.NET MVC

I'm having some issues in updating and inserting records using ASP.NET MVC and Entity Framework.
I have a form (which is a report) that is dynamically created and can have any amount of questions. I'm trying to allow the user to edit the report and submit the changes so that it is updated in the database.
I am retrieving the report to be edited from the database via a repository then setting it to an instance of ModeratorReport. I'm then changing the value of the properties and using db.SaveChanges to save the changes to the database.
The problem is that it is not saving the changes.
Please could someone advise me on what I am doing wrong?
Here is the Edit Action:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Edit(FormCollection formCollection, int moderatorReportId, string status)
{
ModeratorReport reportToEdit = repository.GetModeratorReportById(moderatorReportId);
List<QuestionAnswer> originalReportAnswers = repository.GetAllModeratorReportAnswers(moderatorReportId, status).ToList();
foreach (QuestionAnswer answer in originalReportAnswers) {
reportToEdit.QuestionAnswers.Remove(answer);
}
int sectionID;
int questionID;
foreach (string key in formCollection.AllKeys)
{
var value = formCollection[key.ToString()];
Match m = Regex.Match(key, "section(\\d+)_question(\\d+)");
if (m.Success) {
QuestionAnswer newAnswer = new QuestionAnswer();
sectionID = Convert.ToInt16(m.Groups[1].Value.ToString());
questionID = Convert.ToInt16(m.Groups[2].Value.ToString());
newAnswer.ModeratorReportID = moderatorReportId;
newAnswer.SectionID = sectionID;
newAnswer.QuestionID = questionID;
newAnswer.Answer = value;
newAnswer.Status = "SAVED";
reportToEdit.QuestionAnswers.Add(newAnswer);
}
}
reportToEdit.Status = "SAVED";
AuditItem auditItem = new AuditItem();
auditItem.ModeratorReportID = moderatorReportId;
auditItem.Status = "SAVED";
auditItem.AuditDate = DateTime.Now;
auditItem.Description = "The Moderator report..."
auditItem.UserID = User.Identity.Name;
reportToEdit.Audit.Add(auditItem);
db.SaveChanges();
return RedirectToAction("Details", new { id = moderatorReportId });
}

The problem looks like you're just not setting reportToEdit's EntityState to modified. Like so:
reportToEdit.Audit.Add(auditItem);
reportToEdit.EntityState = EntityState.Modified;
db.SaveChanges();
For more information about the EntityState enumeration, see this MSDN article.