How To Make A Custom Strongly Typed Html Helper Method
Dec 2, 2010
Now I found out how to create custom html helpers
using System;
namespace MvcApplication.Helpers {
public class InputlHelper {
public static string Input(this HtmlHelper helper, string name, string text) {
return String.Format("<input name='{0}'>{1}</input>", name, text);
}
}
}
Now how to turn it into a strongly typed helper method InputFor Like it is in the framework?I don't need the Html.TextBoxFor method, I know it exists. I am just curious in how to implement this behavior myself and used this as a simple example.PS. I was looking in the mvc source code but couldn't find a trace of this mysterious TextBoxFor. I only found TextBox. Am I looking at the wrong code?
I was wondering if it is possible to create a custom strongly typed HTML Helper in ASP.NET MVC 2? Creating a regular (read not-strongly-typed) helper is straightforward but i am having difficulty creating strongly typed versions. For example, I would like to create a DatePickerFor html helper...
The strongly typed helpers are now written like this -
<%= Html.TextBoxFor(model => model.State) %>
I need to add a default value to a textbox. In the prior version of Asp.Net MVC it was easy to assign a default value. I thought doing the following would work in MVC 2-
<%= Html.TextBoxFor(model => model.CountyId, new{ value = 840 })%>
This, however, does not work for me in Asp.Net MVC 2. The value is still blank for the textbox. I want to make sure that this isn't some random error that I am having. Has anyone else encountered the same problem? I have searched and searched to find more information on the default property for the html helpers in MVC 2, but I can't find anything. Does anyone out there know how to correctly assign a default value to a textbox in Asp.Net MVC 2?
in the body of a strongly typed view, I get full intellisense for my model.
However, if I put:
<a href="/Projects/Edit/<%=Model.Project.Id %>">
With the script being written within an html property (in this case the href="" property), the intellisense doesn't work.I imagine this is a limitation of VisualStudio, but it seems this is a very common task and should be able to work. Is there a fix for this? Does my version of VisualStudio have a problem?
I am having a trouble while trying to create an entity with a custom view modeled create form. Below is my custom view model for Category Creation form.
[code]....
When i click on save button, it doesnt bind the category for me because of i am using custom view model and strongly typed html helpers like that
I am using the MetaDataType DataAnnotation to validate my models in an MVC2 application. I also apply the DisplayFormat annotation so that currencies and dates are formatted the way I want. This method works for the original Html Helpers such as :
[Code]....
When I used the new strongly typed helpers:
[Code]....
the formatting never gets applied. Is there a way around this?
I try to use HtmlHelper.TextBoxFor with spark view engine but view crashed with exception "Dynamic view compilation failed. 'System.Web.Mvc.HtmlHelper' does not contain a definition for 'TextBoxFor' and no extension method 'TextBoxFor' accepting a first argument of type 'System.Web.Mvc.HtmlHelper' could be found(are you missing a using directive or an assembly reference?)".
It is my _global.spark: <use namespace="System"/> <use namespace="System.Linq"/> <use namespace="System.Text" /> <use namespace="System.Web.Mvc"/> <use namespace="System.Web.Mvc.Html"/> <use namespace="System.Web.Routing"/> <use namespace="System.Linq.Expressions" /> <use namespace="MyModels" /> In spark-view using: ${Html.TextBoxFor(m => m.UserName)}
I have a view that is strongly typed and its model is of type LogOnModel. That LogOnModel has anotated properties like this one:
[Required(ErrorMessage = "Please enter your password")] [DataType(DataType.Password)] [Display(Name = "Password", Description = "Your secreet password")] public string Password { get; set; }
All of them has Display anotation with Display.Descripion property set. I want to create HtmlHelper extension method that will output <span> containg the value of Display.Description property. So for example if I called my extension method DescriptionFor than this code:
<%: Html.DescriptionFor(m => m.Password) %>
should produce following html: <span>Your secreet password</span>
When I send a strongly typed ViewModel containing other ViewModels nested inside (basically spanning 3 tables into one object) all the data is correctly presented when debugging. However it complains at rendering time with an exception "Compiler Error Message: CS1061: 'object' does not contain a definition for 'Name' and no extension method 'Name' accepting a first argument of type 'object' could be found (are you missing a using directive or an assembly reference?)"
and the error is thrown from mvc2-rtm-sourcessrcSystemWebMvcMvcViewPageControlBuilder.cs method: ProcessGeneratedCode line 19
I personally dont like doing this as i find it makes it harder for me to know if someone changed the field name, or mis typed it during development - the other way you won't know until the page loads.
With the strongly typed version if something changes in your DAL etc the build will break - letting me know I've messed up.
Why do so many people appear to use weakly typed code in ASP.Net (in examples, MVC, etc)? Am i missing something?
Given the benefits of using strongly typed views to eliminate typed errors and the use of lambda expressions why would one use a dynamically typed view? When I use them I don't feel as safe as with strongly typed views. Am I missing something? Is there a special use for them?
It's a little unclear for me on when to use a custom helper method and when to use RenderAction and also when to simply use ViewData instead. Some of their functions overlap slightly.
For example, if I were to create a Category navigation bar, would I create a new helper method and place that in some partial view? I had initially though of doing this, but I read on some blog to use RenderAction instead.
Assume the list of categories is coming from some data source.
Can I call Ajax.BeginFrom from a custom helper method ?
AjaxHelper is not available in a custom helper method, so I tried to pass the "Ajax" available in ViewPage to Helper method while calling it, but then in method, BeginForm is not available on that passed "Ajax" parameter.
MVC contains a strong typed HTML Helper (HTML.CehckBoxFor()) this takes a bool and returns a bool. To make the URL smaller I am thinking to change the bool values on the model object to byte or somthing like that so the url only contains &Parameter=1.
I have found this snippet :
[Code]....
But I have no clue how to turn this in to a strong typed HTML Helper for checkbox that takes byte instead of bool. Its also important that the model object is set with byte instead of bool.
