I have Industry type in my database. When it is null, it is showing an error like:
"Nullable object must have a value."
I want my value to display empty when it is null too.
This is my code:
<p>
<strong>Industry Type:</strong>
<%: Model.GetIndustry(Model.IndustryId.Value).Name%>
</p>
Anyone have an idea? Please help me...
It is similar to "von v"'s answer, but I think the error of "Nullable object must have a value." can be from IndustryId since is nullable, so it is good to check for that first:
<p>
<strong>Industry Type:</strong>
<%:if(Model.IndustryId.HasValue)
{
var idustry = Model.GetIndustry(Model.IndustryId.Value);
if(industry!= null)
industry.Name
}
else
{
""
}
%>
</p>
In my view it is good to do this
Model.GetIndustry()
in Back end, like controller, and then return the industry by viewstate,
like checking in the:
string industryName = "";
if(Industry.IndustryId.HasValue){
var industry = YourClass.GetIndustry(Industry.IndustryId.Value);
industryName = industry!= null ? Industry.Name : "" ;
}
ViewBag.IndustryName= industryName;
and then use your ViewBag in view like this:
<p>
<strong>Industry Type:</strong>
<%: ViewBag.IndustryName %>
</p>
It is good to separate the checking from view and do the logics in code.
Hope it helps.
Check that an industry is returned first then write the name if there's any
<%
var industry = Model.GetIndustry(Model.IndustryId.Value);
%>
<%: industry == null ? "" : industry.Name %>
Is IndustryId nullable? Then you can do this
<%
var industry = Model.GetIndustry(Model.IndustryId.GetValueOrDefault(0));
%>
and in the GetIndustry method, you can just return null if the id is zero.
public Industry GetIndustry(int id) {
if (id==0) return null;
// else do your stuff here and return a valid industry
}
string can accept null or empty value, why don't you try string.IsNullOrEmpty(Model.IndustryId.Value)
this is pretty self explanatory. in your controller,
string yourValue = string.empty;
yourValue = Model.GetIndustry(Model.IndustryId.Value).Name;
if(string.IsNullOrEmpty(yourValue))
{
//display your result here!
}
ViewBag.IndustryValue = yourValue;
Please try something along the lines of
<p>
<strong>Industry Type:</strong>
<%: Model.IndustryId.HasValue ? Model.GetIndustry(Model.IndustryId.Value).Name : string.Empty%>
</p>
I found the Problem.
<p>
<strong>Industry Type:</strong>
<% if (Model.IndustryId.HasValue)
{ %>
<%: Model.GetIndustry(Model.IndustryId.Value).Name%>
<%}
else
{ %>
<%:Model.IndustryId==null ? "": Model.GetIndustry(Model.IndustryId.Value).Name %>
<%} %>
</p>
Related
I have a form that posts a single value, but I cant seem to get it to the controller. I have verified the value exists in the form, but it arrives at the controller as null. Here is the form post:
<%Html.BeginForm("SaveRecord", "NewApplicant", FormMethod.Post, new { id = Model.PersonModel.ApplicantID } ); %>
<%: Html.Hidden("NewId", Model.PersonModel.ApplicantID) %>
<input type="submit" class="SKButton" value="Save" title="Save this new application as a unique record." />
<% Html.EndForm(); %>
and here is the contoller action:
public ActionResult SaveRecord(NewApplicantViewModel model)
{
int NewAppId = model.PersonModel.ApplicantID;
I have also tried:
public ActionResult SaveRecord(int NewId)
{
model.PersonModel.ApplicantID = NewId;
These must be a simple fix, and I want to pass the id in the model, dont want to use ajax. Thoughts?
Try using:
<%: Html.HiddenFor(model => model.PersonModel.ApplicantID) %>
I have an MVC3 page with an object (Header) that has data and a list of objects (Details) that I want to update on a single page. On the details object I have custom validation (IValidatableObject) that also needs to run.
This appears to generally be working as expected, validations are running and returning ValidationResults and if I put an #Html.ValidationSummary(false); on the page it displays those validations. However I don't want a list of validations at the top, but rather next to the item being validated i.e. Html.ValidationMessageFor which is on the page, but not displaying the relevant message. Is there something I'm missing? This is working on other pages (that don't have this Master-Details situation), so i'm thinking it is something about how I'm going about setting up the list of items to be updated or the editor template for the item?
Edit.cshtml (the Header-Details edit view)
#foreach (var d in Model.Details.OrderBy(d => d.DetailId))
{
#Html.EditorFor(item => d, "Detail")
}
Detail.ascx (the Details Editor Template)
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<Detail>" %>
<tr>
<td>
<%= Model.Name %>
<%= Html.HiddenFor(model => model.DetailId) %>
</td>
<td class="colDescription">
<%= Html.EditorFor(model => model.Description) %>
<%= Html.ValidationMessageFor(model => model.Description) %>
</td>
<td class="colAmount">
<%= Html.EditorFor(model => model.Amount) %>
<%= Html.ValidationMessageFor(model => model.Amount) %>
</td>
</tr>
Model is Entity Framework with Header that has Name and HeaderId and Detail has DetailId, HeaderId, Description and Amount
Controller Code:
public ActionResult Edit(Header header, FormCollection formCollection)
{
if (formCollection["saveButton"] != null)
{
header = this.ProcessFormCollectionHeader(header, formCollection);
if (ModelState.IsValid)
{
return new RedirectResult("~/saveNotification");
}
else
{
return View("Edit", header);
}
}
else
{
return View("Edit", header);
}
}
[I know controller code can be cleaned up a bit, just at this state as a result of trying to determine what is occuring here]
IValidatableObject implementation:
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
if (this.Name.Length < 5) && (this.Amount > 10))
{
yield return new ValidationResult("Item must have sensible name to have Amount larger than 10.", new[] { "Amount" });
}
}
I would recommend you to use real editor templates. The problem with your code is that you are writing a foreach loop inside your view to render the template which generates wrong names for the corresponding input fields. I guess that's the reason why you are doing some workarounds in your controller action to populate the model (header = this.ProcessFormCollectionHeader(header, formCollection);) instead of simply using the model binder to do the job.
So let me show you the correct way to achieve that.
Model:
public class Header
{
public IEnumerable<Detail> Details { get; set; }
}
public class Detail : IValidatableObject
{
public int DetailId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
public int Amount { get; set; }
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
if ((this.Name ?? string.Empty).Length < 5 && this.Amount > 10)
{
yield return new ValidationResult(
"Item must have sensible name to have Amount larger than 10.",
new[] { "Amount" }
);
}
}
}
Controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new Header
{
Details = Enumerable.Range(1, 5).Select(x => new Detail
{
DetailId = x,
Name = "n" + x,
Amount = 50
}).OrderBy(d => d.DetailId)
};
return View(model);
}
[HttpPost]
public ActionResult Index(Header model)
{
if (ModelState.IsValid)
{
return Redirect("~/saveNotification");
}
return View(model);
}
}
View (~/Views/Home/Index.cshtml):
#model Header
#using (Html.BeginForm())
{
<table>
<thead>
<tr>
<th>Name</th>
<th>Description</th>
<th>Amount</th>
</tr>
</thead>
<tbody>
#Html.EditorFor(x => x.Details)
</tbody>
</table>
<button type="submit">OK</button>
}
Editor template for the Detail type (~/Views/Shared/EditorTemplates/Detail.ascx or ~/Views/Shared/EditorTemplates/Detail.cshtml for Razor):
<%# Control
Language="C#"
Inherits="System.Web.Mvc.ViewUserControl<MvcApplication1.Controllers.Detail>"
%>
<tr>
<td>
<%= Html.DisplayFor(model => model.Name) %>
<%= Html.HiddenFor(model => model.DetailId) %>
<%= Html.HiddenFor(model => model.Name) %>
</td>
<td class="colDescription">
<%= Html.EditorFor(model => model.Description) %>
<%= Html.ValidationMessageFor(model => model.Description) %>
</td>
<td class="colAmount">
<%= Html.EditorFor(model => model.Amount) %>
<%= Html.ValidationMessageFor(model => model.Amount) %>
</td>
</tr>
Here are a couple of things that I did to improve your code:
I performed the ordering of the Details collection by DetailId at the controller level. It's the controller's responsibility to prepare the view model for display. The view should not be doing this ordering. All that the view should do is display the data
Thanks to the previous improvement I git rid of the foreach loop in the view that you were using to render the editor template and replaced it with a single #Html.EditorFor(x => x.Details) call. The way this works is that ASP.NET MVC detects that Details is a collection property (of type IEnumerable<Detail>) and it will automatically look for a custom editor templated inside the ~/Views/SomeController/EditorTemplates or ~/Views/Shared/EditorTemplates folders called Detail.ascx or Detail.cshtml (same name as the type of the collection). It will then render this template for each element of the collection so that you don't need to worry about it
Thanks to the previous improvement, inside the [HttpPost] action you no longer need any ProcessFormCollectionHeader hacks. The header action argument will be correctly bound from the request data by the model binder
Inside the Detail.ascx template I have replaced <%= Model.Name %> with <%= Html.DisplayFor(model => model.Name) %> in order to properly HTML encode the output and fill the XSS hole that was open on your site.
Inside the Validate method I ensured that the Name property is not null before testing against its length. By the way in your example you only had an input field for the Description field inside the template and didn't have a corresponding input field for the Name property, so when the form is submitted this property will always be null. As a consequence I have added a corresponding hidden input field for it.
I have been having an issue with updating a nullable bool value using TryUpdateModel. I have a template created to handle the values as so:
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<System.Boolean?>" %>
<% if (ViewData.ModelMetadata.IsNullableValueType) { %>
<%= Html.DropDownListFor(model => model, new SelectListItem[] { new SelectListItem() { Text = "", Value = "null"},new SelectListItem() { Text = "Yes", Value = "true"}, new SelectListItem() { Text = "No", Value = "false" }})%>
<% } else { %>
<%= Html.CheckBoxFor(model => model.Value)%>
<% } %>
My View looks like this:
<%=Html.EditorFor(model => model.TestField) %> //which looks/acts correctly
The SQL Server Database types are also defined correctly as a nullable bit.
My Code is straight forward:
var so = new SomeObject();
if (ModelState.IsValid)
{
//gets to here
if (TryUpdateModel(so))
{
//never gets here
}
}
The Error reported for ModelState on that field is: "The value 'null' is not valid for TestField."
This seems pretty straight forward, but I wasn't able to find anything on this. Any help would be greatly appreciated.
Cheers,
Brian
Since nobody has answered my question, I will put my workaround up. It's not super elegant, but it works. If I wanted it to be pretty, it'd be in a pink font. ;)
Basically I had to load "so" (someObject) manually using the form Collection like so...
var so = new SomeObject();
if (ModelState.IsValid)
{
so.WasItFound = StringToNullBool(form["WasItFound"]);
so.WhereWasItFound = form["WhereWasItFound"];
//fill in the rest of the properties using the form Collection...
}
private bool? StringToNullBool(string s)
{
if (s != "null")
return Convert.ToBoolean(s);
else
return null;
}
I want to display error messages in my view. What is the best way to do this?
What replaces the "???" in my code below? I don't want to simply use Html.ValdiationSummary because right now I'm thinking I need to process the list myself and place certain error messages in different places. For example, the code below would actually need to be expanded to put some of the error messages in a floating div, while others may be displayed at the top of the page.
Is there a better way to do this altogether? e.g. Should I be using an entirely different approach to passing error messages from my controller to the view?
My Controller:
public ActionResult ForgotUsername(ForgotUsernameModel model)
{
...
if (!Users.CheckUsername(model.UserName)) {
ModelState.AddModelError("", "That username does not exist.");
}
....
return View(model);
}
My View:
....
<%
if (???) {
foreach (KeyValuePair<string, ModelState> item in ViewData.ModelState) {
if (item.Value != null && item.Value.Errors != null && item.Value.Errors.Count > 0) {
foreach (ModelError e in item.Value.Errors) {
Response.Write(String.Format("<div>{0}</div>", e.ErrorMessage));
}
}
}
}
%>
<% if (!ViewData.ModelState.IsValid) { %>
<%= Html.ValidationSummary(true) %>
<% } %>
or simply:
<%= Html.ValidationSummary(true) %>
How can I get access to a variable in a View which was created in a Controller?
Either put the variable into the Model that you are using for your View
Or use a ViewBag variable - e.g. from http://weblogs.asp.net/hajan/archive/2010/12/11/viewbag-dynamic-in-asp-net-mvc-3-rc-2.aspx
public ActionResult Index()
{
List<string> colors = new List<string>();
colors.Add("red");
colors.Add("green");
colors.Add("blue");
ViewBag.ListColors = colors; //colors is List
ViewBag.DateNow = DateTime.Now;
ViewBag.Name = "Hajan";
ViewBag.Age = 25;
return View();
}
and
<p>
My name is
<b><%: ViewBag.Name %></b>,
<b><%: ViewBag.Age %></b> years old.
<br />
I like the following colors:
</p>
<ul id="colors">
<% foreach (var color in ViewBag.ListColors) { %>
<li>
<font color="<%: color %>"><%: color %></font>
</li>
<% } %>
although hopefully you'll be using Razor :)
You need to send the variable to the view in the ViewModel (the parameter to the View() method) or the TempData dictionary.
You can add it to the ViewData[] dictionary or the (newer) ViewBag dynamic.
In your controller:
ViewData['YourVariable'] = yourVariable;
// or
ViewBag.YourVariable = yourVariable;
In your view:
<%: ViewData["yourVariable"] %>
// or
<%: ViewBag.YourVariable %>