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How to return a key for the whole model in FluentValidation

Imagine, you have this model
public Class SomeModel
{
public string someString1 { get; set; }
public string someString2 { get; set; }
}
Now you want to validate this model. In FluentValidation you write this.RuleFor(m => m.{property} for each property on the model/class and when a validation error occurs, you get the key of the property that failed validation and a message.
Now, what i am wondering about, is how you can set a key for the whole model when it returns an error from validation, which validates two or more properties. (e.g. this.RuleFor(m => m).TestIfPropsAreEqual(); ) What is the correct way to approach this problem? I don't really want to write the method on a property, because that wouldn't be correct, because you are validating the whole model not a specific property.
EDIT: Forgot to mention that when validating the whole model, the returned key is empty.

https://fluentvalidation.net/start#overriding-the-property-name is the answer. I can give the a name to class or new name to a property.

Ninject bind property on view models to filter

I'm fairly new to ninject so you'll have to forgive the potentially stupid question. I have been able to successfully bind my own custom filter to controller actions, however my question is can I do the same to a property on a ViewModel? My scenario is thus:
I have a view model with properties that look like this
public class CreateViewModel
{
...
[PopulateWith(typeof(Country))]
public IEnumerable<SelectListItem> Countries { get; set; }
...
}
the attribute is is a simple class
public class PopulateWithAttribute : Attribute
{
public Type Type { get; }
public PopulateWithAttribute(Type t)
{
Type = t;
}
}
and all I want to be able to do is have a block of code that will run when a new instance of CreateViewModel is created, that will take the database context to hydrate the enumeration. I'm not sure if even an action filter is the correct route to go down like how you make custom authorization / logging functionality. It doesn't seem that the BindFilter<> has anything that points to being able to bind on properties...
A point in any direction or to any resources would be great.

Pre-processing Form data before Model validation in MVC

I am fairly new to MVC, but have quite a bit of experience in development in general, and am having an issue with MVC request life cycle it seems.
Will try to keep this simple, even tho the project is a bit complex in some areas.
I have a view bound to a view model that has a few complex list properties. These properties are displayed via checkboxes who's IDs are not directly related to any property in the model, but instead related to the IDs of the objects in the List<>. Because of this, the checked values do not automatically get applied to the model on POST.
To get around that, I added code in the Action method in the controller that parses the proper controls (in the Request.Form collection) and assigns the checked/selected value to the proper list items in the model.
This works perfectly up to a point.
Now, I also use Fluent Validation, and the problem is when performing custom validation rules when posting a new model to the server. The Validation routine is firing BEFORE the controller's action method, and thus before my processing of the list objects.
So, my question is, is there a way I can override the initial call to the model validation so I can just call the validation manually after my processing? I know I can do that which will fix the problem without overriding the initial call, but some of the validation takes a bit of time to process since it requires linq queries to a live database, so I do not want the validation to fire 2 times - that will quite literally double the time it takes to return no matter if the model is valid or not.
EDIT: Adding a example:
namespace Models
{
[Validator(typeof(MemberValidator))]
public class ViewMember
{
public int MemberID { get; set; }
public short RegionID { get; set; }
public List<PropTypeInfo> PropTypes { get; set; }
}
}
PropTypeInfo class:
public class PropTypeInfo
{
public byte ID { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public bool Selected { get; set; }
public PropTypeInfo(byte i, string n, string d, bool sel)
{
ID = i;
Name = n;
Description = d;
Selected = sel;
}
public static List<PropTypeInfo> GetAll(bool selected = false)
{
List<PropTypeInfo> output = new List<PropTypeInfo>();
OpenAccess.Context context = new OpenAccess.Context();
var list = (from f in context.Prop_Types orderby f.PropType select f).ToList();
foreach (OpenAccess.WebrentzServerPayments.Models.Prop_Type p in list)
output.Add(new PropTypeInfo(p.PropType, p.PropName, p.DisplayText, selected));
return output;
}
}
now here is the code in the view that renders the checkboxes for each item in the list:
<div class="Column Emp-PropTypes">
#foreach (WebrentzServerPayments.Models.PropTypeInfo ptype in Model.PropTypes)
{
<div style="float:right;width:20%;font-weight:bold;">
#Html.CheckBox("ptype_" + ptype.ID, ptype.Selected, new {Value=ptype.ID}) #Html.Raw(" ") #ptype.Name
</div>
}
</div>
And here is the code I use in the Controller Action method to pull that data back in to the List:
foreach (PropTypeInfo info in member.PropTypes)
info.Selected = form[string.Format("ptype_{0}", info.ID)].Contains(info.ID.ToString());
As a little background, a "PropType" is a type of property (house, condo, apartment) - there are about 2 dozen of them, and more can be added/removed at any time. The list in the class called "PropTypes" is first populated with the Name, Description and ID from a table in the database that lists all the available proptypes for that region.
We then will mark the proptypes as "selected" if the user has chosen that particular type. Those are saved to a table called Member.PropTypes (MemberID, ProptypeID).
So, at runtime the list will contain one record for each available proptype and the selected property will be set to yes if that user has selected it. That makes it easy to render the full list in the view...
Its actually quite a bit more complex as there are almost a dozen such lists, but each works the exact same way just with different data, as well as about 200 additional properties that are easier to manage. Only these lists are causing the issue.
Any help appreciated!
Dave

Getting error at time of binding ListBoxFor control in MVC4

When I am changing the "model => model.id" to "model => model.Supplierid" i am getting below error
"The parameter 'expression' must evaluate to an IEnumerable when
multiple selection is allowed."
please have look on below code
// this my model class
public class clslistbox{
public int id { get; set; }
public int Supplierid { get; set; }
public List<SuppDocuments> lstDocImgs { get; set; }
public class SuppDocuments
{
public string Title { get; set; }
public int documentid { get; set; }
}
public List<SuppDocuments> listDocImages()
{
List<SuppDocuments> _lst = new List<SuppDocuments>();
SuppDocuments _supp = new SuppDocuments();
_supp.Title = "title";
_supp.documentid = 1;
_lst.Add(_supp);
return _lst;
}
}
// this my controller
[HttpGet]
public ActionResult AddEditSupplier(int id)
{
clslistbox _lst = new clslistbox();
_lst.lstDocImgs= _lst.listDocImages();
return View(_lst);
}
// this is view where i am binding listboxfor
#model clslistbox
#using (Html.BeginForm("AddEditSupplier", "Admin", FormMethod.Post))
{
#Html.ListBoxFor(model => model.id, new SelectList(Model.lstDocImgs, "documentid", "title"))
}
Can anyone see the reason for it?

I think the changing of the property in the expression here is a red-herring - it won't work in either case.
Update
However, see at the end of my answer for some probably needlessly detailed exposition on why you didn't get an error first-time round.
End Update
You're using ListBoxFor - which is used to provide users with multiple selection capabilities - but you're trying to bind that to an int property - which cannot support multiple selection. (It needs to be an IEnumerable<T> at least to be able to bind a list box to it by default in MVC)
I think you mean to be using DropDownListFor - i.e. to display a list of items from which only one can be selected?
If you're actually looking for single-selection semantics in a listbox, that's trickier to do in MVC because it's Html helpers are geared entirely around listboxes being for multiple selection. Someone else on SO has asked a question about how to get a dropdown to look like a list box: How do I create a ListBox in ASP.NET MVC with single selection mode?.
Or you could generate the HTML for such a listbox yourself.
(Update) - Potentially needlessly detailed exposition(!)
The reason you don't get an exception first time round is probably because there was no value for id in ModelState when the HTML was generated. Here's the reflected MVC source (from SelectExtensions.SelectInternal) that's of interest (the GetSelectListWithDefaultValue call at the end is the source of your exception):
object obj =
allowMultiple ? htmlHelper.GetModelStateValue(fullHtmlFieldName, typeof(string[])) :
htmlHelper.GetModelStateValue(fullHtmlFieldName, typeof(string));
if (!flag && obj == null && !string.IsNullOrEmpty(name))
{
obj = htmlHelper.ViewData.Eval(name);
}
if (obj != null)
{
selectList =
SelectExtensions.GetSelectListWithDefaultValue(selectList, obj, allowMultiple);
}
Note first that the control variable allowMultiple is true in your case, because you've called ListBoxFor. selectList is the SelectList you create and pass as the second parameter. One of the things that MVC (unfortunately in some cases) does is to use ModelState to modify the select list you pass when re-displaying a view in order to ensure that values which were set in ModelState via a POST are re-selected when the view is reloaded (this is useful when page validation fails because you won't copy the values to your underlying model from ModelState, but the page should still show those values as being selected).
So as you can see on the first line, the model's current value for the expression/field you pass is fished out of model state; either as a string array or as a string. If that fails (returns null)then it makes another go to execute the expression (or similar) to grab the model value. If it gets a non-null value from there, it calls SelectExtensions.GetSelectListWithDefaultValue.
As I say - what you're trying to do will ultimately not work in either the case of Id or SupplierId (because they would need to be IEnumerable) but I believe this ModelState->Eval process is yielding a null value when you use Id, so the process of getting an 'adjusted' SelectList is skipped - so the exception doesn't get raised. The same is not true when you use SupplierId because I'll wager that there's either a value in ModelState at that point, or the ViewData.Eval successfully gets an integer value.
Not throwing an exception is not the same as working!.
End update

Try changing your property from int to int[]
public class SuppDocuments
{
public string Title { get; set; }
public int documentid { get; set; }
}
Assuming above is the class used for binding the model , try changing the documentid property as below
public class SuppDocuments
{
public string Title { get; set; }
public int[] documentid { get; set; }
}

Passing and returing data to a simple grid form using ASP.NET MVC

I have page with a simple table and advanced search form. I pass List<Customers> to the model:
View(List<Customers>);
So what is best way to pass and return data to the search form? I want to use validation or something but I think passing data through ViewData is not good idea. Any suggestions?

You should wrap all your data that is required by you view in a model specific to that view. The advantage to this is you could also include your search criteria in the model which would be empty at first but when your search posted, the model would automatically contain your search criteria so you could reload it when passing back the results. This will help maintain your state between post's as well.
This also allows all your view's data to be type safe where ViewData would not be.
Eg:
public class CustomerSearchViewModel
{
public List<Customer> Customers { get; set; }
// your search criteria if you want to include it
public string SearchFirstName { get; set; }
public string SearchLastName { get; set; }
public int SearchCustomerID { get; set; }
// etc...
}
When you return back the List<Customer> the search criteria would already be filled in your model from the post so your view can default the search criteria back to the corresponding controls (assuming your search results and search inputs controls are on the same view).
For example, in your post you would accept a CustomerSearchViewModel. Then all you need to do is get your list of customers and add it back to the model and return the same model.
// assuming you have accepted a CustomerSearchViewModel named model
model.Customers = GetCustomersForSearchCriteria(model.SearchFirstName,
model.SearchLastName, model.SearchCustomerID);
return View(model);
You could also add the validation attributes to your model properties to leverage the built in validation in MVC. This would not be possible if you were using ViewData to pass this data around.
You have to also consider the 'next guy'. It's cleaner when all the data that the view requires is located in a single class. This way they don't have to hunt through the code to discover if ViewData is being used and what data is actually being passed around in it.
ViewData is still an option for passing data but I try to minimize the use of it if at all possible.

Rather than passing just a list of items to your View, create a class which contains your list of items and any other data you might need, i.e. a ViewModel.
public class CustomerSearchViewModel {
public IEnumerable<Customer> Customers { get; set; }
public string SearchTerm { get; set; }
}
.....
var viewModel = new CustomerSearchViewModel {
Customers = customerList,
SearchTerm = searchTerm
};
return View(viewModel);