I am new to ASP.NET MVC and was/am not sure exactly how to word my problem. I have to create a page where the user can add a list of multiple collateral items to a loan application. Each "row" for each collateral items needs several Dropdownlist to select the type of collateral, its class etc. The page is based on a ViewModel:
public class CollateralViewModel
{
public Guid LoanApplicationId { get; set; }
public IEnumerable<CollateralRowViewModel> Collateral { get; set; }
}
The IEnumerable Collateral gets the following:
public class CollateralRowViewModel
{
public Guid Id { get; set; }
public Guid LoanApplicationId { get; set; }
public IEnumerable<SelectListItem> CollateralClass { get; set; }
public IEnumerable<SelectListItem> CollateralType { get; set; }
public Guid SelectedCollateralType { get; set; }
public Guid SelectedCollateralClass { get; set; }
[DataType(DataType.MultilineText)]
public string Description { get; set; }
public decimal? MarketValue { get; set; }
public decimal? PriorLiens { get; set; }
public decimal? AdvanceRate { get; set; }
public string GrantorFirstName { get; set; }
public string GrantorMiddleName { get; set; }
public string GrantorLastName { get; set; }
}
My Controller looks like this:
public async Task<ActionResult> Create(CollateralViewModel collateralViewModel)
{
var collateralServiceProxy = base.ServiceProvider.CollateralServiceProxy;
var collateralTypes = await GetCollateralTypesByClass(Guid.NewGuid());
var selectedCollateral = collateralViewModel.Collateral.Select(collateral => new Collateral()
{
Id = collateral.Id,
LoanApplicationId = collateral.LoanApplicationId,
CollateralTypeId = collateral.SelectedCollateralType,
Description = collateral.Description,
GrantorFirstName = collateral.GrantorFirstName,
GrantorMiddleName = collateral.GrantorMiddleName,
GrantorLastName = collateral.GrantorLastName,
PriorLiens = collateral.PriorLiens,
MarketValue = collateral.MarketValue
});
foreach (var collateral in selectedCollateral)
{
await collateralServiceProxy.PutCollateralAsync(collateral);
}
return View(collateralViewModel);
}
private async Task<IEnumerable<SelectListItem>> GetCollateralClasses()
{
var collateralServiceProxy = base.ServiceProvider.CollateralServiceProxy;
var collateralClasses = await collateralServiceProxy.GetAllCollateralClassesAsync();
if (collateralClasses == null)
{
return new List<SelectListItem>();
}
return collateralClasses.ToSelectList();
}
private async Task<IEnumerable<SelectListItem>> GetCollateralTypesByClass(Guid collateralClassId)
{
var allCollateralTypes = await GetAllCollateralTypes();
var selectedCollateralTypes = allCollateralTypes.Where(collateralType => Guid.Parse(collateralType.Value).Equals(collateralClassId));
return selectedCollateralTypes;
}
When I try to use #Html.DropDownListFor(model=>model.Collateral.CollateralClasses) I cannot because CollateralClasses is unavailable. I type "(model.Collateral." and the properties aren't there. What am I doing wrong here?
Any help is greatly appreciated!!
Please check you dropdownlistfor syntex. I think that may be the issue (because you have not specified the error).Please check the syntex
#Html.DropDownListFor(m => m.ContribType,
new SelectList(Model.ContribTypeOptions,
"ContribId", "Value",
Model.ContribTypeOptions.First().ContribId))
so you may try it like this. In your first place "valueItRepresent", it should be the property for which the dropdown is for
#Html.DropDownListFor(model => model.valueItRepresent, model.Collateral.FirstOrDefault().CollateralClasses as SelectList, "Select")
The issue is your dropdownlist not populated when rendering the UI. You have to properly populate dropdownlist before render data.This can be done in several ways, but I would recommend reading below article.
This article provide solution for your question
http://odetocode.com/blogs/scott/archive/2013/03/11/dropdownlistfor-with-asp-net-mvc.aspx
Hope this helps.
Related
Hi have a problem with auomapper where i try to use the Automapper.Mapper(src, dest) without loosing the values in the dest after doing the mapping.
I have a class which has a list of objects like below
public class UpdateShipmentDetailDto
{
public bool IsDocument { get; set; }
public List<UpdateItemDetailDto> ItemDetails { get; set; } = new();
}
which i want to map to
public class SCS_OUT_Manifest
{
public Guid ManifestId { get; set; }
public ICollection<SCS_OUT_ManifestItem> SCS_OUT_ManifestItems { get; set; } = new List<SCS_OUT_ManifestItem>();
}
The UpdateItemDetailDto class looks like this
public class UpdateItemDetailDto
{
public Guid ItemId { get; set; }
public string ItemDescription { get; set; }
public int Qty { get; set; }
public Guid UnitsId { get; set; }
public decimal ItemValue { get; set; }
}
And the SCS_OUT_ManifestItem class looke like
public class SCS_OUT_ManifestItem
{
public Guid ItemId { get; set; }
public Guid ManifestId { get; set; }
public string ItemDescription { get; set; }
public int Qty { get; set; }
public Guid UnitsId { get; set; }
public decimal ItemValue { get; set; }
}
Im performing a maaping like below, which map from ItemDetails (which is a list) to SCS_OUT_ManifestItems (which is also a ICollection).
_mapper.Map(updateShipmentDetailDto.ItemDetails, manifest.SCS_OUT_ManifestItems);
The problem after mapping is done the properties which in the destination collection are set to the default values.
for example the ManifestId inthe SCS_OUT_ManifestItem manifest.SCS_OUT_ManifestItems which is not in updateShipmentDetailDto.ItemDetails is set to its default Guid value 00000000-0000-0000-0000-000000000000.
But if i run this in a loop like below it works.
foreach (var item in manifest.SCS_OUT_ManifestItems)
{
_mapper.Map(updateShipmentDetailDto.ItemDetails.Single(s => s.ItemId == item.ItemId), item);
}
Please help! thanks in advance
Try map your lists and your itens and use the same name ÏtemDetails" in both lists.
var config = new MapperConfiguration(cfg =>
{
cfg.CreateMap<UpdateItemDetailDto, SCS_OUT_ManifestItem>();
cfg.CreateMap<UpdateShipmentDetailDto, SCS_OUT_Manifest>();
});
var _mapper = config.CreateMapper();
var updateShipmentDetailDto = new UpdateShipmentDetailDto();
var updateItemDetailDto = new UpdateItemDetailDto();
var manifest = new SCS_OUT_Manifest();
updateItemDetailDto.ItemId = Guid.NewGuid();
updateItemDetailDto.UnitsId = Guid.NewGuid();
manifest.ManifestId = Guid.NewGuid();
updateItemDetailDto.ItemDescription = "test";
updateItemDetailDto.Qty = 10;
updateItemDetailDto.ItemValue = 25.50M;
updateShipmentDetailDto.ItemDetails = new List<UpdateItemDetailDto>();
updateShipmentDetailDto.ItemDetails.Add(updateItemDetailDto);
_mapper.Map(updateShipmentDetailDto.ItemDetails, manifest.ItemDetails);
Console.WriteLine($"DTO Guid: {updateShipmentDetailDto.ItemDetails[0].ItemId}, Desc: {updateShipmentDetailDto.ItemDetails[0].ItemDescription}");
foreach (var item in manifest.ItemDetails)
{
Console.WriteLine($"Guid: {item.ItemId}, Desc: {item.ItemDescription}");
}
Console.WriteLine($"Guid Manifest: {manifest.ManifestId}");
This a simple project where users can search for job postings by area of expertise. The relationship between Areas and Postings are Many-to-many. I seem to be able to get to the very last part of retrieving the correctly filtered list, but getting back into the view model keeps giving me different errors:
ViewModel:
public class AreaOfertasViewModel
{
public Oferta UnaOferta { get; set; }
public SelectList AreasTrabajo { get; set; }
public IEnumerable<Oferta> Ofertas { get; set; }
public int idArea { get; set; }
public AreaOfertasViewModel()
{
this.UnaOferta = UnaOferta;
this.Ofertas = new List<Oferta>();
cargarAreas();
}
private void cargarAreas()
{
PostulaOfertaContext db = new PostulaOfertaContext();
this.AreasTrabajo = new SelectList(db.Areas, "areaId", "Area");
}
}
}
Controller:
public ActionResult SearchXArea()
{
return View(new AreaOfertasViewModel());
}
[HttpPost]
public ActionResult SearchXArea(AreaOfertasViewModel aovm)
{
int id = aovm.idArea;
PostulaOfertaContext db = new PostulaOfertaContext();
var area = db.Areas.Where(c => c.areaId == id);
var ofertas = from c in db.Ofertas.Where(r => r.AreaTrabajo == area)
select c;
aovm.Ofertas = (IEnumerable<Oferta>)ofertas.ToList();
return View(aovm);
}
The line giving me issues is
aovm.Ofertas = (IEnumerable)ofertas.ToList();
I've tried List<> for Ofertas, and I've tried leaving it as .ToList() without casting, and casting it as different things, but it gives me errors about not being able to cast it, and "Cannot compare elements of type 'System.Collections.Generic.List`1'. Only primitive types, enumeration types and entity types are supported."
What's the solution here?
Model for AreaTrabajo:
public class AreaTrabajo
{
[Key]
public int areaId { get; set; }
public string Area { get; set; }
public virtual List<Oferta> oferta { get; set; }
}
Model for Oferta:
public class Oferta
{
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
[Required]
public string Titulo { get; set; }
[Required]
public DateTime Vencimiento { get; set; }
[Required]
public string Cargo { get; set; }
[Required]
public int HorarioComienzo { get; set; }
[Required]
public int HorarioFin { get; set; }
[Required]
public string DescripcionTareas { get; set; }
public int Remuneracion { get; set; }
[Required]
public int RangoEdadMin { get; set; }
[Required]
public int RangoEdadMax { get; set; }
public string TipoFormacion { get; set; }
public string Idiomas { get; set; }
public string Competencias { get; set; }
public string OtrosEstudios { get; set; }
public string Estado { get; set; }
public virtual List<AreaTrabajo> AreaTrabajo { get; set; }
public virtual TipoContrato TipoContrato { get; set; }
public virtual Empresa Empresa { get; set; }
public virtual List<Postulante> Postulantes { get; set; }
}
Answer
[HttpPost]
public ActionResult SearchXArea(AreaOfertasViewModel aovm)
{
int id = aovm.idArea;
PostulaOfertaContext db = new PostulaOfertaContext();
var area = db.Areas.Where(c => c.areaId == id).FirstOrDefault();
var ofertas = db.Ofertas.Where(s => s.AreaTrabajo.All(e => e.areaId == area.areaId)).ToList();
aovm.Ofertas = ofertas;
return View(aovm);
}
Sorry if my question wasn't clear enough. I needed to filter out from the many-to-many relationship, and this solved it.
You are getting an error because the actual sql is executed when you call tolist(). The error is in your sql because you are comparing AreaTrabago to a list.
[HttpPost]
public ActionResult SearchXArea(AreaOfertasViewModel aovm)
{
int id = aovm.idArea;
PostulaOfertaContext db = new PostulaOfertaContext();
var area = db.Areas.Where(c => c.areaId == id).FirstOrDefault();
var ofertas = db.Ofertas.Where(s => s.AreaTrabajo.All(e => e.areaId == area.areaId)).ToList();
aovm.Ofertas = ofertas;
return View(aovm);
}
Sorry if my question wasn't clear enough. I couldn't get the many-to-many relationship, and this solved the filtering problem perfectly.
I'm trying to sort out this issue but as I'm learning a lot of this stuff as I go along I'd really appreciate it if someone could explain where I'm going wrong and/or some good resources where I can read up.
So, I have a model based on my Entity Framework model of my database and a viewmodel representing properties in that model. I've built a Kendo grid to display the data (defined in a js file) and the method in the contoller returns a Json result set. Trouble is, when I try to display a value in a joined db table, if there hasn't been a key value set, I get a nullreferenceexception error. Obviously I'm missing part of the puzzle here as there must be a way of coding this to stop it happening. Any help would be gratefully received!
My model is like this:
namespace TrainingKendoUI.Models
{
using System;
using System.Collections.Generic;
public partial class TRAINING_EMPLOYEE_COURSES
{
public int EMP_COURSE_ID { get; set; }
public int EMPLOYEE_ID { get; set; }
public int COURSE_ID { get; set; }
public Nullable<System.DateTime> DATE_ATTENDED { get; set; }
public Nullable<decimal> COURSE_COST { get; set; }
public string COURSE_RESITS { get; set; }
public Nullable<int> PROVIDER_ID { get; set; }
public Nullable<int> EMP_COURSE_STATUS_ID { get; set; }
public Nullable<int> VENUE_ID { get; set; }
public virtual TRAINING_COURSES TRAINING_COURSES { get; set; }
public virtual TRAINING_EMPLOYEE_COURSE_STATUS TRAINING_EMPLOYEE_COURSE_STATUS { get; set; }
public virtual TRAINING_EMPLOYEES TRAINING_EMPLOYEES { get; set; }
public virtual TRAINING_PROVIDERS TRAINING_PROVIDERS { get; set; }
public virtual TRAINING_VENUES TRAINING_VENUES { get; set; }
}
}
My controller method looks like this:
public JsonResult EmployeeCourses_Read()
{
var model = db.TRAINING_EMPLOYEE_COURSES;
var ViewModel = new List<EmployeeCoursesIntersectionViewModel>();
foreach (var employee in model)
{
ViewModel.Add(new EmployeeCoursesIntersectionViewModel(employee));
}
return Json(ViewModel, JsonRequestBehavior.AllowGet);
}
and my view model lilke this:
namespace TrainingKendoUI.ViewModels
{
public class EmployeeCoursesIntersectionViewModel
{
#region Constructors
public EmployeeCoursesIntersectionViewModel()
{
}
public EmployeeCoursesIntersectionViewModel(TRAINING_EMPLOYEE_COURSES model)
{
this.empCourseId = model.EMP_COURSE_ID;
this.employee = model.TRAINING_EMPLOYEES.FIRST_NAME;
this.course = model.TRAINING_COURSES.COURSE_NAME;
this.dateAttended = model.DATE_ATTENDED;
this.cost = model.COURSE_COST;
this.resits = model.COURSE_RESITS;
//These lines will produce a NullReference error if not set through the front end...
this.provider = model.TRAINING_PROVIDERS.PROVIDER_NAME;
this.status = model.TRAINING_EMPLOYEE_COURSE_STATUS.EMP_COURSE_STATUS;
this.venue = model.TRAINING_VENUES.VENUE_NAME;
}
#endregion
#region Properties
public int empCourseId { get; set; }
public string employee { get; set; }
public string course { get; set; }
public Nullable<System.DateTime> dateAttended { get; set; }
public Nullable<decimal> cost { get; set; }
public string resits { get; set; }
public string provider { get; set; }
public string status { get; set; }
public string venue { get; set; }
#endregion
}
}
Do a null check on the object before setting it, i.e.
this.provider = model.TRAINING_PROVIDERS == null ? ""
: model.TRAINING_PROVIDERS.PROVIDER_NAME;
and you'll have to do similar for status and venue
this.status = model.TRAINING_EMPLOYEE_COURSE_STATUS== null ? ""
model.TRAINING_EMPLOYEE_COURSE_STATUS.EMP_COURSE_STATUS;
this.venue = model.TRAINING_VENUES== null ? ""
model.TRAINING_VENUES.VENUE_NAME;
So I have a model that contains a list of models which contains items, and so on, like this:
public partial class CART
{
public CART()
{
//this.CART_DETAIL = new HashSet<CART_DETAIL>();
this.CART_DETAIL = new List<CART_DETAIL>();
}
public int CART_IDE { get; set; }
public int CART_COUNT { get; set; }
public string SHOPPING_CART_IDE { get; set; }
public virtual IList<CART_DETAIL> CART_DETAIL { get; set; }
}
public partial class CART_DETAIL
{
public int CART_DETAIL_IDE { get; set; }
public int CART_IDE { get; set; }
public int CART_DETAIL_COUNT { get; set; }
public Nullable<int> PACK_IDE { get; set; }
public Nullable<int> BACKSTORE_INVENTORY_IDE { get; set; }
public virtual CART CART { get; set; }
public virtual PACK PACK { get; set; }
public virtual BACKSTORE_INVENTORY BACKSTORE_INVENTORY { get; set; }
}
public partial class BACKSTORE_INVENTORY
{
public BACKSTORE_INVENTORY()
{
this.CART_DETAIL = new HashSet<CART_DETAIL>();
this.ORDER_DETAIL = new HashSet<ORDER_DETAIL>();
}
public int BACKSTORE_INVENTORY_IDE { get; set; }
public int INVENT_IDE { get; set; }
public int STORE_IDE { get; set; }
public decimal BACKSTORE_INVENTORY_PRICE { get; set; }
public int BACKSTORE_STOCK_QTY { get; set; }
public decimal BACKSTORE_DISCOUNT { get; set; }
public decimal BACKSTORE_SELLING_PRICE { get; set; }
public virtual INVENTORY INVENTORY { get; set; }
public virtual STORE STORE { get; set; }
public virtual ICollection<CART_DETAIL> CART_DETAIL { get; set; }
public virtual ICollection<ORDER_DETAIL> ORDER_DETAIL { get; set; }
}
When I open a connection and consult the data, everything's fine, but if I retrive the whole data in a view, for example, unless I modify the Hashset to a List and then proceed like this:
CART cart =
db.CART.FirstOrDefault(_item => _item.SHOPPING_CART_IDE == mShoppingCartID && _item.CART_ACTIVE_INDICATOR);
if (cart != null)
{
cart.CART_EXP_TIME = DateTime.Now.AddMinutes(90);
cart.USER_SESSION_IDE = UserSessionManager.GetUserSession().mUserSessionID;
cart.CART_DETAIL = cart.CART_DETAIL.ToList();
foreach (var cartDetail in cart.CART_DETAIL)
{
if(cartDetail.BACKSTORE_INVENTORY_IDE != null)
{
cartDetail.BACKSTORE_INVENTORY =
db.BACKSTORE_INVENTORY.First(_item => _item.BACKSTORE_INVENTORY_IDE == cartDetail.BACKSTORE_INVENTORY_IDE);
cartDetail.BACKSTORE_INVENTORY.INVENTORY =
db.INVENTORY.Find(cartDetail.BACKSTORE_INVENTORY.INVENT_IDE);
cartDetail.BACKSTORE_INVENTORY.INVENTORY.CARD =
db.CARD.Find(cartDetail.BACKSTORE_INVENTORY.INVENTORY.CARD_IDE);
}
else
{
cartDetail.PACK = db.PACK.First(_item => _item.PACK_IDE == cartDetail.PACK_IDE);
}
}
db.SaveChanges();
}
I get the following error: CS0021: Cannot apply indexing with [] to an expression of type 'System.Collections.Generic.ICollection<MyApp.Models.DAL.Entities.CART_DETAIL>' which I understand is because the ICollection does not afford indexing, and then I get The ObjectContext instance has been disposed and can no longer be used for operations that require a connection. for items that I forgot to retrive.
So my question: what makes this happen? Is there a way to retrieve all the data at once without having to get all specific items separately? A better way to do things?
What are you trying to achieve form the above code?
I am struggling to follow what your end goal is but would something along these lines be what you are looking for:
public List<Cart> GetAllInCart()
{
return db.CART.Where(a => a.Cart_IDE == CartIDE)
.Include(x => x.Cart_Detail)
.Include(x => x.Cart_Detail.Pack)
.Include(x => x.Cart_Detail.Backstore_Inventory)
.ToList()
}
I hope this helps :)
Getting the "Collection was modified" exception when attempting to add to a collection
public void UpdateLinks(EventViewModel form)
{
var selectedIds = form.Links.Select(r => r.ResourceTypeID).ToList();
var assignedIds = form.Event.Links.Select(r => r.ResourceTypeID).ToList();
foreach (var resource in form.Links)
{
resource.EventID = form.Event.ID;
if (!assignedIds.Contains(resource.ResourceTypeID))
form.Event.Links.Add(resource);
}
foreach (var resource in form.Event.Links.ToList())
{
if (!selectedIds.Contains(resource.ResourceTypeID))
form.Event.Links.Remove(resource);
}
}
The problem is specifically with the "Add" method. If I comment that part out, no exception is thrown. It's important to note that I've already tried re-writing the foreach as a for loop and adding "ToList()" to form.Links. The same exception is thrown in all cases. I use this exact pattern on other parts of the site without issue which is why this is so frustrating. This also works on "Create". The problem only affects the "Edit" action.
Other relevant code:
[HttpPost]
public ActionResult Edit(EventViewModel form, HttpPostedFileBase[] eventFiles)
{
if (ModelState.IsValid)
{
eventsService.UpdateEvent(form.Event);
eventsService.UpdateManufacturerTags(form);
eventsService.UpdateFiles(form, eventFiles);
eventsService.UpdateLinks(form);
eventsService.Save();
return RedirectToAction("Details", new { id = form.Event.ID });
}
return View(form);
}
public class EventViewModel : ContentLeftViewModel
{
public Event Event { get; set; }
public string[] SelectedManufacturers { get; set; }
public MultiSelectList Manufacturers { get; set; }
public IList<EventResource> Files { get; set; }
public IList<EventResource> Links { get; set; }
public EventViewModel()
{
SelectedManufacturers = new string[0];
Files = new List<EventResource>();
Links = new List<EventResource>();
}
}
public class Event
{
[Key]
public int ID { get; set; }
[Required]
public string Title { get; set; }
[Required]
[DisplayName("Start Time")]
[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:M/d/yyyy h:mm tt}")]
public DateTime? StartTime { get; set; }
[Required]
[DisplayName("End Time")]
[DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:M/d/yyyy h:mm tt}")]
public DateTime? EndTime { get; set; }
public string Venue { get; set; }
public string Address { get; set; }
public string City { get; set; }
public string State { get; set; }
public string Zip { get; set; }
[AllowHtml]
[DataType(DataType.MultilineText)]
public string Description { get; set; }
[DisplayName("Registration Link")]
public string RegistrationUrl { get; set; }
public virtual IList<Manufacturer> Manufacturers { get; set; }
public virtual IList<EventResource> Files { get; set; }
public virtual IList<EventResource> Links { get; set; }
//public IEnumerable<EventResource> Resources
//{
// get { return Files.Concat(Links); }
//}
public string StartDate
{
get { return StartTime.Value.ToShortDateString(); }
}
public string StartTimeOnly
{
get { return StartTime.Value.ToShortTimeString(); }
}
public string EndDate
{
get { return EndTime.Value.ToShortDateString(); }
}
public string EndTimeOnly
{
get { return EndTime.Value.ToShortTimeString(); }
}
public Event()
{
Manufacturers = new List<Manufacturer>();
Files = new List<EventResource>();
Links = new List<EventResource>();
}
}
public class EventResource
{
[Key, Column(Order = 0)]
public int EventID { get; set; }
[Key, Column(Order = 1)]
public int ResourceTypeID { get; set; }
[Key, Column(Order = 2)]
public string Path { get; set; }
public virtual Event Event { get; set; }
public virtual ResourceType Type { get; set; }
}
UPDATE
Some more info: Adding to the collection at all... even outside of a loop throws the same error. Does that give anyone an idea?
Try this instead:
var lsEvents = form.Event.Links.ToList();
foreach (var resource in form.Links)
{
resource.EventID = form.Event.ID;
if (!assignedIds.Contains(resource.ResourceTypeID))
lsEvents.Add(resource);
}
foreach (var resource in form.Event.Links)
{
if (!selectedIds.Contains(resource.ResourceTypeID))
lsEvents.Remove(resource);
}
and Use lsEvents according to the requirement. This will fix your issue.
You can use LINQ to filter out entries before adding them.
public void UpdateLinks(EventViewModel form)
{
var selectedIds = form.Links.Select(r => r.ResourceTypeID).ToArray();
var assignedIds = form.Event.Links.Select(r => r.ResourceTypeID).ToArray();
foreach (var resource in form.Links
.Where(r=> !assignedIds.Contain(r.ResourceTypeID)).ToArray())
{
resource.EventID = form.Event.ID;
form.Event.Links.Add(resource);
}
foreach (var resource in form.Event.Links
.Where(r=> !selectedIds.Contain(r.ResourceTypeID)).ToArray())
{
form.Event.Links.Remove(resource);
}
}
In both methods, we are filtering resources before enumerating and adding. You can not enumerate and add at the same time.
You can't modify a collection you are enumerating (e.g., for each).
You need to loop once to get the items you want to add and/or remove, then add or remove all of them in a second loop outside the first.
E.g.:
Dim coll = New List(of String)({"1", "2", "3", "4", "6"})
dim coll2 = New List(of String)({"5", "8", "9", "2"})
Dim removeItems as new list(of String)()
For Each item in coll
For Each item2 in coll2
If item2 = item
removeItems.Add(item)
end if
Next item2
Next item
' remove the items gathered
For each itemToRemove in removeItems
coll.Remove(itemToRemove)
Next itemToRemove
It can be done a better way, but this shows the gist of the error. You can't change the collection you are looping over.
Not sure exactly what was responsible for solving the issue, but after upgrading to Visual Studio 2013 Express (from 2010 Professional), and installing ASP.Net 4.5/IIS8 with it, even though this application continues to target ASP.Net 4.0, I am no longer experiencing the issue and the code used in the original post works as is.
Perhaps this was caused by a certain build of the ASP.Net framework or an older version of IIS?