i have been playing around with MVC. I am currently stumped on with html helper methods. One thing i have noticed is that I cant really cant apply the ASP.NET Web Form logic into MVC. To explain further, in ASP.NET I could create a Label control and assign it some text data and then read the text data.
However, in MVC, I cant seem to do the same with #Html.LabelFor/#Html.Label, I have realised that once you do a POST from your form, the value from the Label is not bound back into my view model. However, if I use an EditorFor or TextBoxFor, I can get values bound to my viewmodel upon POST.
My question what html hlper method should I use to display text as readonly but yet be able to bind back to my viewmodel upon post ? I have tried TextBoxFor with its html attributes set to disabled and readonly but no luck.
Appreciate any pointers.
thanks
You should be able to bind the readonly attribute to the TextBox by passing in htmlAttributes as the 2nd parameter of the TextBoxFor method:
<%=Html.TextBoxFor(m => m.SomeProperty, new { #readonly = "readonly" }) %>
On MSDN: InputExtensions.TextBoxFor Method (HtmlHelper, Expression>, Object)
If you're trying to maintain the Label value you can use a combination of the LabelFor and HiddenFor methods.
I don't know why you would need to do this though, since you should be able to get the DisplayText attribute or the Property Name from the property.
<%=Html.LabelFor(m => m.SomeProperty) %>
<%=Html.HiddenFor(m => m.SomeProperty) %>
but this doesn't make a lot of sense since the usual syntax would be:
<%=Html.LabelFor(m => m.SomeProperty) %>
<%=Html.TextBoxFor(m => m.SomeProperty) %>
Note that if you use the disabled attribute the input will not be posted when the form is submitted
This is expected behaviour, only values form elements are added to your Model on POST so your label will be ignored. To get around this duplicate your label value in a hidden field
Html.HiddenFor(model => model.FieldName)
or
Html.Hidden("FieldName", model.FieldName)
Related
I have a partial view that allows Html and the rendered name attribute of the <textarea> is throwing everything off, for instance this is my text area
#Html.TextAreaFor(model => model.cars.mycars)
causes the attribute to render as name="cars.mycars", is there anyway to change that to cars_mycars without using #Name ?
The reason why I want cars_mycars is because it is a field that has AllowHtml in it in the model
[AllowHtml]
public string mycars { get; set; }
In order for AllowHtml to work I would need a strongly typed model such as #Html.TextAreaFor(model => model.mycars) but I am using multiple models in 1 view therefore I have
#Html.TextAreaFor(model => model.cars.mycars, #new{id="cars_mycars",#Name="cars_mycars"})
This is all in a partialview and when I try to submit it nothing happens at all. That is the only field in the form so the issue much lie there and in addition if I put
ValidateInput(False)
on the action method then everything works fine which leads me back to the #name convention not working .
You can try like this
#Html.TextArea("cars_mycars")
when using
<%= Html.DropDownListFor(model => model.FeeTypeId, Model.GetFeeTypes(), new { })%>
in this case the right option is selected according to Model.FeeTypeId when the select is rendered.
BUT
if you render the form using a partial view, passing it a specific HtmlFieldPrefix (you will need it if,for example, you want to render two identical views and want different ids the elements)
<% Html.RenderPartial("path-to-partial-view", Model, new ViewDataDictionary() { TemplateInfo = new TemplateInfo() { HtmlFieldPrefix = "myPrefix" } }); %>
then the value will not be selected.
looks similar to the problem at DropDownListFor in EditorTemplate not selecting value but from different cause.
looked in the MVC 3 source and seems like the problem is at the SelectInternal method
it uses the htmlHelper.ViewData.Eval(fullName);
which fails to get the value by the full name when it contains the prefix,
TextBoxFor doesn't fail as it passes the value of the expression to InputHelper so it doesn't get to use the ViewData.Eval
just to be sure tested it at the partial view:
in the partial view the following will print "myPrefix.FeeTypeId"
<%= Html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName("FeeTypeId") %>
and the following will print "by property name: [value] by full name: [empty string]"
<%="by property name: " + Html.ViewData.Eval("FeeTypeId")%><br />
<%= "by full name: " + Html.ViewData.Eval(Html.ViewContext.ViewData.TemplateInfo.GetFullHtmlFieldName("FeeTypeId"))%>
The only solution i found is to generate a List at Model.GetFeeTypes() and mark the option i want as selected:
<%= Html.DropDownListFor(model => model.FeeTypeId, Model.GetFeeTypes(Model.FeeTypeId), new { })%>
don't really like this solution + i know i can create the List in the partial view which is also ugly,
is there another solution to this?
I have discovered that this is a bug in MVC. It's not fixed, though there is a work around.
See my question answered by myself (I had the same problem before finding your post).
MVC4 binding drop down list in a list (bug)
Regards
Craig
I am using a DropDownListFor like this:
#Html.DropDownListFor(model => model.SelectedOrganisationValue, new SelectList(Model.OrganisationList, "Value", "Text"))
And I am also using:
[Required]
As Attribute in the View.
So when I PostBack the View to the Server and the Required Attribute will fail, the View is showed again, but then Model is null. So I will get a NullReferenceException in Model.OrganisationList.
That is the default behaviour. As you know ,MVC does not rely on ViewState, It can not keep the content inside the drop down across Postbacks (generic term). You need to repopulate it again in the ActionMethod.
I have a url like this:
http://localhost/products/AddFeature?code=SMW
in the controller action, I create a model and set the
model.Code = "123112".
The View has this
#Html.EditorFor(model => model.Code)
the final rendered html always shows "SMW" as the value.
Is this a bug where the query string value overrides the assigned value ?
Does anyone got same results or I need some coffee ?
Clear the model state before returning your view. Be sure that you haven't missed some model error before you do that. The helpers use the ModelState, then the models for their values.
ModelState.Clear();
This code was converted from some ASP.Net MVC 2 code in this tutorial:
MVC 2 Editor Template with DateTime
It is a custom EditorTemplate for DateTime fields stored as 'EditorTemplates/DateTime.cshtml'.
#Model DateTime?
#Html.TextBox("", (Model.HasValue ? Model.Value.ToShortDateString() : string.Empty), new { #class = "datePicker" })
However I get the following error when using #Html.EditorFor(model => model.NewAbsence.StartDate):
CS1973: 'System.Web.Mvc.HtmlHelper' has no applicable method named 'TextBox' but appears to have an extension method by that name. Extension methods cannot be dynamically dispatched. Consider casting the dynamic arguments or calling the extension method without the extension method syntax.
I've seen some similar posts on here which mention casting the parameter of the EditorFor method, however I cannot seem to get this to work in my example.
Could someone please point out what I will need to change in my code. Thanks.
Actually it's #model with lowercase m:
#model DateTime?
^
instead of:
#Model DateTime?
So to sort of summarize what people are saying, and make it a bit more generic. If your view is declaring that it accepts dynamic models:
#model dynamic
Then things like extension methods will not be able to infer the types of arguments passed to them. Here are two examples (using Razor because it's awesome):
#Html.TextBox("myTextBoxName", Model.MyTextBoxValue)
#Html.DropDownList("myDropDownName", Model.MySelectList))
In these cases, the engine doesn't know what types Model.MyTextBoxValue or Model.MySelectList are, therefore it can't figure out what overloads of the extension methods to compile. So you just help it along with some strong typing:
#Html.TextBox("myTextBoxName", (string)Model.MyTextBoxValue)
#Html.DropDownList("myDropDownName", (SelectList)Model.MySelectList))
By the way, just to stop people from potentially pulling out their hair, that SelectList has to be properly instantiated with something like:
var items = List<SelectListItem>();
...
new SelectList(items, "Value", "Text");
As a temporary work around I am using:
<div class="editor-field date-field">
#Html.EditorFor(model => model.NewAbsence.StartDate)
#Html.ValidationMessageFor(model => model.NewAbsence.StartDate)
</div>
Then using the jQuery selector:
$(".date-field > input").datepicker({
showOn: "button",
buttonImage: "*pathtoimage*"
});
To apply the date picker to the input tags within the 'date-field' div. However this still doesn't format the date value how I want it to display initially, and cuts out the editor template entirely.
The error message comes from your textbox statement. In a template, this becomes a dynamic expression, and .Net doesn't know how to type the Model properties.
#Html.TextBox("", (string)(Model==null ? Model.Value.ToShortDateString() : string.Empty), new { style = "width: 10em;", #class="datefield" })
Explicitly cast your date value as string, and the dynamic expression has the information it needs. I also had a problem with the .HasValue property, but that wasn't the point of your question.