I have a class. At one point, I had set the properties of the class to [Required] using System.ComponentModel....
Okay, then I realized this was not needed. I have removed the required property but when I try to submit the form to an ActionResult the form does NOT post and still is trying to enforce the TextBoxFor(theModelProperty) to be populated.
I have deleted the "obj" folder, the "bin" folder, and also "Cleaned" the solutions. Still NO resolution.
I don't want to do a stupid workaround, I would like to do things correctly. Any idea why this occurs?
You have two options:
Set property as nullable,
Turn off required attribute for value
types (see this answer)
If you have value type properties. Client validation will always generate required validations. If you don't want required validation for value types make them nullable.
Related
Is it possible to safely programmatically get a list of fields that are in the View that has just posted back to a Controller?
I noticed a problem with the default implementation of the scaffolding, in
DB.Entry(model).State = EntityState.Modified
DB.SaveChanges()
The problem is that if I haven't included a field to be edited in the view, it is being overwritten by the default value of the field that .NET assigns when creating the object. eg. If I have a User class with ID, Email and PasswordHash and I want to allow the user to update their Email address only, if I don't include anything for the PasswordHash field, it is reset to NULL as it is passed into the controller as NULL. At the moment, I am working around it by retrieving the current object from the database and updating only the fields which I know are in the View from the model passed in. That isn't such a problem for a small table, but I would like to have a general solution that I can apply across the board, especially for large tables which may during development and I don't want to have to update the code every time.
I know that I could loop through the POST variables and examine them to see what has been posted, but that creates a security issue as the user could inject additional fields that I don't want them to edit. I suppose I could explicitly exclude ones that I don't want them to edit, but then again, I would rather not have to list those if I can avoid it as it is an extra thing to maintain.
I think that there are 2 problems here and I'm not sure either are solvable...
Getting the View that posted back
Establishing which fields are included in that View (I might need to construct it again temporarily to do that?)
I suppose that I can probably get away with ignoring the first one as I could just only ever use that method on the Controller for a single View. That is still a little less neat than I'd like, but it does reduce the issue to just establishing which fields are in the View.
If a view needs only certain properties, create an interface with only those properties. Use this interface in the HttpGet and HttpPost methods.
And then you can use something like AutoMapper to map the viewmodel to your entity.
Very simple question that NO ONE has directly answered. Is there no way to insert an entity using EF4 that uses the database default constraint and yet allows that field to be updated later? There doesn't seem to be. When I have a date property for instance and want it to use the database default, I seem to have two options:
1) Set the "StoreGeneratedPattern" to "Computed" or "Identity" which prevents me from updating it later.
2) Ignore the database default entirely and set the default value myself.
Neither one of these options will work for me, and this seems to be a huge weakness with the framework. Any ideas? Is this bug resolved in EF5.
No.
Relevant UserVoice suggestion.
You could extend the generated class and set the default values in the constructor of the patial class.
public partial MyEntityClass MyEntity
{
public MyEntityClass()
{
this.DefaultValueProperty = defaultValue;
}
}
I'm working on my first ASP.NET MVC (beta for version 3) application (using EF4) and I'm struggling a bit with some of the conventions around saving a new record and updating an existing one. I am using the standard route mapping.
When the user goes to the page /session/Evaluate they can enter a new record and save it. I have an action defined like this:
[ActionName("Evaluate")]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult EvaluateSave(EvaluteSessionViewModel evaluatedSession)
{
}
When they save I grab an entity off the view model and attach it to my context and save. So far, so good. Now I want the user to be able to edit this record via the url /session/Evaluate/1 where '1' is the record ID.
Edit: I have my EF entity attached as a property to the View Model.
If I add an overloaded method, like this (so I can retrieve the '1' portion automatically).
[ActionName("Evaluate")]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult EvaluateSave(ID, EvaluteSessionViewModel evaluatedSession)
{
}
I get an "The current request for action 'Evaluate' on controller type 'SessionsController' is ambiguous between the following action" error. I'm not sure why they're ambiguous since they look unique to me.
I decided that I was just going to skip over this issue for now and see if I could get it to update an existing record, so I commented out the EvaluateSave that didn't have the ID parameter.
What I'd like to do is this:
// Load the original entity from EF
// Rebind the postback so that the values posted update the entity
// Save the result
Since the entity is populated as the parameter (evaluatedSession) the rebinding is happening too soon. But as I look at the approach I'd like to take I realized that it opens my code up to hacking (since a user could add in fields into the posted back page and these could override the values I set in the entity).
So it seems I'm left with having to manually check each field to see if it has changed and if it has, update it. Something like this:
if (evaluatedSession.MyEntity.myField <> savedSession.myField)
savedSession.myField = evaluatedSession.MyEntity.myField;
Or, save a copy of the entity and make sure none of the non-user editable ones have changed. Yuck.
So two questions:
First: how do I disambiguate the overloaded methods?
Second: is there a better way of handling updating a previously saved record?
Edit: I guess I could use something like Automapper...
Edit 9/22/2010 - OK, it looks like this is supposed to work with a combination of two items: you can control what fields bind (and specifically exclude some of them) via the [Bind(Exclude="field1,field2")] attribute either on the class level or as part of the method doing the saving, ex.
public ActionResult EvaluateSave([Bind(Exclude="field1")] EvaluateSessionViewModel evaluatedSession)
From the EF side of things you are supposed to be able to use the ApplyCurrentValues() method from the context, ex.
context.ApplyCurrentValues(savedEval.EntityKey.EntitySetName, evaluatedSession);
Of course, that doesn't appear to work for me. I keep getting "An object with a key that matches the key of the supplied object could not be found in the ObjectStateManager. Verify that the key values of the supplied object match the key values of the object to which changes must be applied.".
I tried attaching the original entity that I had just loaded, just in case it wasn't attached to the context for some reason (before ApplyCurrentValues):
context.AttachTo(savedEval.EntityKey.EntitySetName, savedEval);
It still fails. I'm guessing it has something to do with the type of EF entity object MVC creates (perhaps it's not filled in enough for EF4 to do anything with it?). I had hoped to enable .NET framework stepping to walk through it to see what it was attempting to do, but it appears EF4 isn't part of the deal. I looked at it with Reflector but it's a little hard for me to visualize what is happening.
Well, the way it works is you can only have one method name per httpverb. So the easiest way is to create a new action name. Something like "Create" for new records and "Edit" for existing records.
You can use the AntiForgeryToken ( http://msdn.microsoft.com/en-us/library/dd492767.aspx ) to validate the data. It doesn't stop all attempts at hacking but it's an added benefit.
Additional
The reason you can only have one action name per httpverb is because the model binders only attempt to model bind and really aren't type specific. If you had two methods with the same action name and two different types of parameters it can't just try and find the best match because your intent might be clearly one thing while the program only sees some sort of best match. For instance, your might have a parameter Id and a model that contains a property Id and it might not know which one you intend to use.
PLEASE NOTE: I've answered my own question with a link to an answer to a similar question. I'll accept that answer once I'm allowed to (unless anyone comes up with a better answer meantime).
I have a database column defined as NVARCHAR(1000) NOT NULL DEFAULT(N'') - in other words, a non-nullable text column with a default value of blank.
I have a model class generated by the Linq-to-SQL Classes designer, which correctly identifies the property as not nullable.
I have a TextAreaFor in my view for that property. I'm using UpdateModel in my controller to fetch the value from the form and populate the model object.
If I view the web page and leave the text area blank, UpdateModel insists on setting the property to NULL instead of empty string. (Even if I set the value to blank in code prior to calling UpdateModel, it still overwrites that with NULL). Which, of course, causes the subsequent database update to fail.
I could check all such properties for NULL after calling UpdateModel, but that seems ridiculous - surely there must be a better way?
Please don't tell me I need a custom model binder for such a simple scenario...!
Might be duplicate or something in the line of this:
MVC binding form data problem
I fear custom model binder will be necessary. ;)
You might want to use a partial class implementation of your entity that implements the on property changed handler for that particular property. When you detect that the property has been changed to NULL, simply change it to string.Empty. That way anytime NULL is assigned to the property it gets reset to the empty string.
Why is the checkbox not checked with this code?
<td><%=Html.CheckBox("ItemIsActive", item.ItemIsActive)%></td>
Item.ItemIsActive is of type boolean and set to true?
When i do this, it shows "true" in the view
<td><%=item.ItemIsActive%></td>
I had this same issue until I changed my boolean field to a non-nullable field. Make sure your Item.IsActive field is declared like:
bool ItemIsActive {..}
instead of
bool? ItemIsActive {..}
If you are using Linq2Sql make sure ItemIsActive is not nullable in your table.
I had the same problem as well (using ASP.NET MVC).
Actually I had a form with two checkboxes, one where the boolean is nullable and the other non-nullable.
In the case of the non-nullable the checkbox was checked when the value from the database was true. In the case of the nullable I couldn't get it checked using Html.CheckBox.
I solved it by converting the value from the model to non-nullable boolean.
<td><%=Html.CheckBox("ItemIsActive", item.ItemIsActive == null ?
false :
(bool)item.ItemIsActive) %></td>
I've played with this for around 30 minutes now and I have tried the following;
1) Create a checkbox and set to true
2) Create a variable, set to true and use it as the checked flag
3) Create two checkboxes with the same id setting one to false the other to true
All of the above works fine so the (only) thing I can think of is that you may have some css or javascript setting checkboxes back to false. This is easy to do if you are using jQuery.
The fact that there are so few replies to this question seems to indicate that others can't seem to replicate your issue either.
Like I said, I'd be checking my CSS and any Javascript/jQuery I have on the page, partial controls, master etc.
If you have a viewdata item called ItemIsActive, or if your view is tied to a specific model that has a property called that, it will use that over what you specify.
To see if this might be it try changing it to this:
<td><%=Html.CheckBox("ItemIsActive_test", item.ItemIsActive)%></td>
If that works then I would bet something in the viewdata, or in the model is overwriting what item.ItemIsActive contains