What is the replacement for a server control in ASP.NET MVC? What I want to do is to create a declarative and imperative binding so I can write
<cc1:MyControl Header="Some Header" Content="Some Content" />
which would mean that an instance of the MyControl class will be created and possibly rendered to
<h1>Some Header</h1>
<p>Content</p>
I don't want any viewstate or postback crap, just the modularity. I also want these modules to be contained in a separate class library, so ViewUserControls will not do for me. Using a server controls in the normal way works, but it generates a form tag and a viewstate field, which I do not want if I can avoid it.
I have seen this question and this one about how to use server controls in ASP.NET MVC, but they do not provide enough answer.
Edit: I found the answer. When I added the user control using the designer, it automatically created a <form> which I missed. If I simply remove that tag, everything works perfectly.
You can still use all controls in ASP.NET MVC if they don't require rendering in a server form.
ascx files and #Register directives still work pretty well. The great new thing is Html.RenderPartial method that lets you pass a model object to a partial view (ascx) and have it render accordingly.
Just adding one more possibility to Mehrdad answer, you can use extension methods to do a simple control like this:
<%= html.MyControl( "Some header", "Some content" ) %>
<Extension()> _
Public Function MyControl(ByVal htmlHelper As HtmlHelper, _
ByVal Header As String, _
ByVal Content As String) As String
Dim sb As New StringBuilder()
sb.AppendFormat("<h1>{0}</h1>", Header)
sb.AppendFormat("<p>{0}</p>", Content)
Return sb.ToString()
End Function
Or you can make a more complex control like this example: Create an ASP.NET MVC GridView Helper Method
Other than the controls which still work with ASP.Net MVC, you can use mvc controls.
Repeater example - dead link
Exploring ASP.Net MVC Futures - dead link
UPDATE: This answer was for ASP.Net MVC 1.0 in 2009. It is outdated and irrelevant at this point.
Related
Using webforms, a control can be defined like this:
<asp:label id="lblDate" runat="server"></asp:label>
and the code behind can manipulate it like this:
lblDate.Text = DateTime.Now.Year.ToString() + " eheheh";
lblDate.ToolTip = "tooltip";
lblDate.BackColor = Color.Red;
...
My question is: is there a similar way to manipulate a control in MVC?
MVC doesn't have server control; instead, it has HtmlHelper.
For example, the following Label Helper will generate the similar HTML mark up redered by WebForm's label control.
#Html.Label("Date", DateTime.Now.Year.ToString(),
new { style = "background-color: red", title="this is tooltip" })
The easiest thing will be for you to use JS or HTML tags while you can do it in the controller it is kinda pointless and too much work for basic properties you could use Ajax for that but like i said too much work. For Clearing textbox use JS. There are things like controls which are essentially JS libraries that have a corresponding .Net Libraries and you can build objects for the view and control them from Controller, usually those are for advanced and more rich features you add to your web site.
How can I use custom controls with ASPNET.MVC Razor?
I want to use a custom control on a Razor view. for instance:
<mycontrols:something>#Model.MyVar</mycontrols:something>
or
<mycontrols:something myattribute="#Model.MyVar" />
Please note that my goal is to use only few controls derived from MvcControl, only for trivial repetive ui stuffs.
I tried to find out a syntax similar to #Register to write on the top of the view, but without any success.
Then I went to the web.config, adding
<pages>
<controls>
<add tagPrefix="mycontrols" namespace="mynamespace" assembly="myassembly"/>
</controls>
</pages>
but it looks like custom controls are ignored in rendering.
Someone could help?
...Might be it is a little bit old fashion, but sometimes also custom control could be useful to make your code cleaner!
The Razor syntax does not support the notion of Controls at all. If you want to use controls you will have to use the ASPX (WebForms) syntax.
However, the recomended MVC pattern is to use html helper functions or partial views. In Razor you can also use the #helper syntax for quick helper functions.
In ASP.NET MVC custom server controls should be avoided. Most of them rely on ViewState and PostBack which are notions that no longer exist in MVC. You should prefer using templates, HTML helpers to implement some reusable functionality. Another problem with controls is most of them encapsulate some business logic which fetches data from somewhere and renders it which is an anti-MVC pattern. In MVC it is the controller responsibility to manipulate the model and fetch data and pass a view model to the view which simply should display it.
MVC uses partial views rather than custom controls, and they can be used in two ways that cover pretty much everything a custom control can do
RenderPartial which renders data already retrieved by the page controller
RenderAction which is similar but has its own controller action so can get data independently
The only scenario I can think of where it would be worth putting a custom control on an mvc view is if you are working on a partially migrated webforms project, and I doubt that would work with anything other than the WebFormsViewEngine.
You can do this, though I don't recommend it, though I'm not here to judge. I might add that I don't expect postback and view state to continue working either but you can at least render all of the html.
The only way to do this is a bit of a hack, because razor doesn't support webforms view engine controls. However, it does support partial views made in the webforms View engine. So a hacky solution is to include a partial view with your control in it as such:
For example, say you want to use the office web ui ribbon in your mvc3 project, you could do so by including
<body>
<div>
#Html.Partial("_RibbonPartial")
</div>
</body>
in your view. Where _Ribbon is of type .aspx
then in your partial view simply use your control and set runat="server" and put it inside of a form with runat="server"
//_Ribbon.aspx
<form id="form1" runat="server">
<XyzControls:Manager ID="Manager1" runat="server" UITheme="Silver" />
<XyzControls:OfficeRibbon ID="OfficeRibbon1" runat="server" ApplicationMenuColor="#267c29"
ApplicationMenuText="Item" ApplicationMenuType="Backstage">
//... rest of control code
</form>
Then you need to use ajax to implement events instead of using postback.
Then to cleanup, get rid of the generated code from webforms view engine for post back that you don't need.. You can try keeping it, I haven't so I'm not sure what will happen. I know there are ways to have a fake viewstate as well if you really want to get into messy hacky stuff, but to remove the extra code from webforms you can use the following jquery:
$(function ()
{
// we don't need any of the webforms stuff
$("#__EVENTTARGET","#aspnetForm").parents("div:first").remove();
$("#__EVENTVALIDATION","#aspnetForm").parents("div:first").remove();
});
I had the same demand. Wanted to use custom webcontrol from Razor/MVC page. One should not do that with controls, that is handling postback. You don't have the eventcycle to support that, but if your only demand is to use a 'rendering control', you could instantiate it in razor, and control where the rendering takes place:
#{
var myControl = new mycontrols.something();
myControl.myattribute = Model.MyVar;
mycontrol.RenderControl(new HtmlTextWriter(this.Output));
}
I have a lot of content-heavy views in my ASP.NET MVC 2 site. These contain several re-occurring HTML patterns. When using ASP.NET Webforms, a class derived from WebControl could encapsulate these patterns. I'd like some pointers on the correct approach for this problem with MVC.
Detailed Explanation
Patterns not unlike the following HTML markup keep occurring throughout these views. The markup renders into an isolated a box of content:
<div class="top container">
<div class="header">
<p>The title</p>
<em>(and a small note)</em>
</div>
<div class="simpleBox rounded">
<p>This is content.</p>
<p><strong>Some more content</strong></p>
</div>
</div>
This is a trivial example, but there are more complex recurring patterns. In ASP.NET Webforms I would have abstracted such code into a WebControl (let's say I'd have named it BoxControl), being included on a page like this:
<foo:BoxControl runat="server">
<Header>The title</Header>
<Note>(and a small note)</Note>
<Content>
<p>This is content.</p>
<p><strong>Some more content</strong></p>
</Content>
</foo:BoxControl>
This abstraction makes it easy to adapt the way the box is constructed throughout the site, by just altering the BoxControl source. It also keeps the static HTML content neatly together in the View Page, even when combining several BoxControls on a page. Another benefit is that the HTML used as content is recognized by the IDE, thus providing syntax highlighting/checking.
To my understanding, WebControls are discouraged in ASP.NET MVC. Instead of a WebControl, I could accomplish the abstraction with a partial view. Such a view would then be included in a View Page as follows:
<%= Html.Partial("BoxControl", new {
Header="The Title",
Note="(and a small note)",
Content="<p>This is content.</p><p><strong>Some more content</strong></p>"});
%>
This is not ideal, since the 'Content' parameter could become very long, and the IDE does not treat it as HTML when passed this way.
Considered Solutions
Strongly-Typed ViewModels can be passed to the Html.Partial call instead of the lengthy parameters shown above. But then I'd have to pull the content in from somewhere else (a CMS, or Resource file). I'd like for the content to be contained in the View Page.
I have also considered the solution proposed by Jeffrey Palermo, but that would mean lots of extra files scattered around the project. I'd like the textual content of any view to be restricted to one file only.
Should I not want to abstract the markup away? Or is there maybe an approach, suitable for MVC, that I am overlooking here? What is the drawback to 'sinning' by using a WebControl?
There is a solution to this problem, although the way to get there is a little more clutsy than other frameworks like Ruby on Rails.
I've used this method to create markup for Twitter Bootstrap's control group syntax which looks like this:
<div class="control-group">
<label class="control-label">[Label text here]</label>
<div class="controls">
[Arbitrary markup here]
</div>
</div>
Here's how:
1) Create a model for the common markup snippet. The model should write markup on construction and again on dispose:
using System;
using System.Web.Mvc;
namespace My.Name.Space
{
public class ControlGroup : IDisposable
{
private readonly ViewContext m_viewContext;
private readonly TagBuilder m_controlGroup;
private readonly TagBuilder m_controlsDiv;
public ControlGroup(ViewContext viewContext, string labelText)
{
m_viewContext = viewContext;
/*
* <div class="control-group">
* <label class="control-label">Label</label>
* <div class="controls">
* input(s)
* </div>
* </div>
*/
m_controlGroup = new TagBuilder("div");
m_controlGroup.AddCssClass("control-group");
m_viewContext.Writer.Write(m_controlGroup.ToString(TagRenderMode.StartTag));
if (labelText != null)
{
var label = new TagBuilder("label");
label.AddCssClass("control-label");
label.InnerHtml = labelText;
m_viewContext.Writer.Write(label.ToString());
}
m_controlsDiv = new TagBuilder("div");
m_controlsDiv.AddCssClass("controls");
m_viewContext.Writer.Write(m_controlsDiv.ToString(TagRenderMode.StartTag));
}
public void Dispose()
{
m_viewContext.Writer.Write(m_controlsDiv.ToString(TagRenderMode.EndTag));
m_viewContext.Writer.Write(m_controlGroup.ToString(TagRenderMode.EndTag));
}
}
}
2) Create a nifty Html helper
using System.Collections.Generic;
using System.Linq;
using System.Web.Mvc;
using My.Name.Space
namespace Some.Name.Space
{
public static class FormsHelper
{
public static ControlGroup ControlGroup(this HtmlHelper helper, string labelText)
{
return new ControlGroup(helper.ViewContext, labelText);
}
}
}
3) Use it in the view (Razor code)
#using (Html.ControlGroup("My label"))
{
<input type="text" />
<p>Arbitrary markup</p>
<input type="text" name="moreInputFields" />
}
This is also the way MVC framework renders a form with the Html.BeginForm method
Well you wouldn't render the partial like that, pass it a strongly-typed ViewModel, like this:
<%= Html.RenderPartial("BoxControl", contentModel) %>
contentModel is the ViewModel (just a POCO-like storage mechanism for your views), which the strongly typed partial view would bind to.
So you can do this in your partial view:
<h1><%: Model.Header %></h1>
<p><%: Model.Content %></p>
etc etc
After considering the answers and running an experiment, I'm inclined to adhere to the pure MVC approach and duplicate some presentation code throughout View Pages. I'd like to elaborate on the rationale for that decision.
Partial View
When using a Partial View, The content for the box needs to be passed as a View Model, making the View Page less readable versus declaring the content HTML on the spot. Remember that the content does not come from a CMS, so that would mean filling the View Model with HTML in a controller or setting a local variable in the View Page. Both of these methods fail to take advantage of IDE features for dealing with HTML.
WebControl
On the other hand, a WebControl-derived class is discouraged and also turns out to have some practical issues. The main issue that the declarative, hierarchical style of traditional ASP.NET .aspx pages just does not fit the procedural style of MVC.NET View Pages. You have to choose for either a full blown traditional approach, or go completely MVC.
To illustrate this, the most prominent issue in my experimental implementation was one of variable scope: when iterating a list of products, the MVC-way is to use a foreach loop, but that introduces a local variable which will not be available in the scope of the WebControl. The traditional ASP.NET approach would be to use a Repeater instead of the foreach. It seems to be a slippery slope to use any traditional ASP.NET controls at all, because I suspect you'll soon find yourself needing to combine more and more of them to get the job done.
Plain HTML
Forgoing the abstraction at all, you are left with duplicate presentation code. This is against DRY, but produces very readable code.
It doesnt look like webforms has that much less html to me, it seems more like a lateral move. Using a partial in MVC can make it cleaner but the html markup you needed will still be there, in one place or another. If its mostly the extra html that bothers you, you might take a look at the NHaml view engine or check out haml
the haml website.
I'm by no means a Haml expert but the html does look a lot cleaner...
.top container
.header
%p
The title
%em
(and a small note)
.simpleBox rounded
%p
This is content.
%p
Some more content
Our designers have come up with button styles for an application which require the addition of <span> tags inside the <a> tags of our links.
In ASP.NET we implemented this by adding an App_Browsers entry for Link Buttons.
How would I go about doing this in ASP.NET MVC?
I've contemplated creating my own versions of all of the various HTML helper functions for creating ActionLinks and RouteLinks but this seems to be quite a 'brute force' way of doing things.
Is there a nice elegant way of doing it?
I know we could write some simple jQuery to do it, but we'd rather have the markup coming out of the server correctly in the first place.
Actually I think writing a new helper is exactly the way I would go. Seems to me that that's exactly what they are there for and it makes them very re-usable too.
You could always write one extension method, that takes another one (one of the built-in ones) as an argument, and wrappes the <span> around your link text before calling it. It should be quite easy to do with lambdas...
public static string SpanLink(this HtmlHelper helper,
string linkText, object args, Action<string> action)
where TController : IController
{
action("<span>" + linkText + "</span>", args);
}
And to call it:
<%= Html.SpanLink<HomeController>("link text", (s) => Html.ActionLink<HomeController>(c => c.Index(s));
(This code is typed directly into the answer field of SO - I haven't even checked it to make sure it compiles. So bear with me if it doesn't work on the first try...)
Ok, this is for me a very tough challenge. We're taking our existing ASP.NET website and converting (redesigning the PL only) to MVC. Our site is very complex. But the hard part is to convert the existing custom controls to MVC equivilant. The custom controls (I am not talking about user controls) are just of course a class currently that inherits System.Web.UI.Control and uses that object throughout. For example, we have some properties at the top of this existing custom class like so:
Dictionary<int, Control> configControls;
DropDownList kControl;
CheckBox confirmBox;
These all are variables of type Web controls in classic ASP.NET.
So I figured maybe what I could do (without building entire new custom controls from scratch) is to use the HtmlHelper object. So I tried this:
(include first the using statement that includes System.Web.MVC.Html at the top of my new custom class in our new web project)
private HtmlHelper helper;
Dictionary configControls;
helper.DropDownList
but this is not working. I guess I can't use this object just like this ?? I figured I can use HtmlHelper in the Dictionary and then make variable types off of helper. but those are just extension methods, not objects
I don't know of an equivalent to something like the generic "Control" we had available to us to inherit from such as in classic ASP.NET. Surely it won't be the same in MVC obviusly (stateless and a completely diff way of doing things) but what can I use in MVC with the same concept sort of?
So I figured maybe what I could do (without building entire new custom controls from scratch) is to use the HtmlHelper object. So I tried this:
(include first the using statement that includes System.Web.MVC.Html at the top of my new custom class in our new web project)
private HtmlHelper helper;
Dictionary configControls;
helper.DropDownList
but this is not working. I don't even know if this approach will work in my custom control. And when I try to use my helper variable, I get no extension methods unless it's inside an existing extension method where the signature has an HtmlHelper param passed in. So when I create that private variable just in my custom class outside, I get nothing in intellisense to choose from when doing "helper.". So do I need to define that object like this: ?
private HtmlHelper htmlHelper = new HtmlHelper();
but it's asking for a ViewContext and an IViewDataContainer as params. If I'm building out a custom method that knows nothing yet about its view (it shouldn't need to) because I'm simply creating strings of HMTL in this custom class to be passed to the Extension method to ultimately spit out fields then maybe I can't use HtmlHelper this way in a custom class like this.
So can I use that object in a way instead of "Control"? Maybe I can even in my dictionary variable use type object in place of control ? I don't know and then cast object to type HtmlHelper when I need to use or reference that value from the dictionary? But for now, I figured I can use HtmlHelper object in the Dictionary and then make variable types off of helper. but those are just extension methods, not objects.
I hope I am making any sense here when you read this.
I just blogged about this last night, some of this might be helpful for you.
WebForms And MVC In Harmony — Almost…
Basically it discusses some options for emulating "WebControls" using MVC.
Additionally, you can still use WebControls like you could before (granted they may not work if they need things like the ViewState). The problem I've discovered with that is you have a disconnect from the inline render code and the WebControls themselves.
I did write this method last night which let you use WebControls with inline code.
using System.Reflection;
using System.IO;
using System.Web.UI;
using System.Web;
using System.Web.Mvc;
public static class MyExtensionMethods {
//example method - renders a webcontrol to the page
public static void RenderControl(this HtmlHelper helper, Control control) {
//perform databinding if needed
MethodInfo bind = control.GetType().GetMethod("DataBind");
if (bind is System.Reflection.MethodInfo) {
bind.Invoke(control, null);
}
//render the HTML for this control
StringWriter writer = new StringWriter();
HtmlTextWriter html = new HtmlTextWriter(writer);
control.RenderControl(html);
//write the output
HttpContext.Current.Response.Write(writer.ToString());
//and cleanup the writers
html.Dispose();
writer.Dispose();
}
}
//then used like...
<% int[] numbers = { 1, 2, 3, 4, 5 }; %>
<% this.Html.RenderControl(new DataGrid() { DataSource = numbers }); %>
Just an interesting concept you might be interested in.
Short of hacking webforms controls into your MVC application, servercontrols with many methods do not map to MVC.
They are replaced by partials and controllers(or subcontrollers if you like that sort of thing).
If all you want to do is render some HTML based on a few parameters, then a Helper is what you are after. Static Class, static methods. If however, you need to keep state, and do a bunch of stateful stuff, then a partial, JS, and controller(or subcontroller) are really what you are after.
Server Controls that manage their own state really are a thing of the past in MVC.
Remember that MVC is an attempt to use the web the way it was meant to work, particularly if you bring REST into the picture. Webforms is a fudge to make the web work like windows forms.
I would create needed business logic, shared partial view (probably, with quite a lot of well structured javascript lines attached) and seperated controller.
Then i would use this bunch of code through partial request technique.
Not sure how much this will be of help but, do have a look at this series of blog post
Custom controls everywhere
Also have a look at the Catharsis project
Web-Application Framework - Catharsis - Part I - New Solution
The codeplex URL for the same is
Catharsis
This project has some good examples of control creating for asp.net mvc.