I'm trying to create an html helper to render a button. As an example this needs to contain -
<button onClick="window.location='/Users/Edit/admin'">
I have tried to do this using TagBuilder but am having issues because MergeAttribute is encoding the html.
e.g.
buttonBuilder.MergeAttribute("onClick", "window.location='" + url.Action(action, controller, routeValues));
gives me -
<button onClick="window.location='/Users/Edit/admin">
Is there a way I can do this so it's not encoded? Or should I be using another method other than TagBuilder?
--EDITED
I almost forget, use the HtmlDecode:
public static class ButtonHelper
{
public static IHtmlString Button(this HtmlHelper html)
{
TagBuilder button = new TagBuilder("button");
button.MergeAttribute("onClick", "window.location='/Users/Edit/admin'");
return new HtmlString(System.Web.HttpUtility.HtmlDecode(button.ToString()));
}
}
Or look it: http://forums.asp.net/t/1377957.aspx/1
I have a label as
<%= Html.Label("");%>
i want to add content to label at runtime, unfortunately it doesn't take any other parameter to create id property for it. can't i create id property for it just similar to asp:label
thanks,
michaeld
No need to use the HtmlHelper functions always and everywhere if they don't fit your need. They're just supposed to make your life easier, not harder. Use good ole HTML here:
<label id="id_for_label"></label>
If you want to keep using HtmlHelper functions you can always create your own extension methods.
For example:
public static class LabelHelper
{
private static string HtmlAttributes(object htmlAttributes)
{
var builder = new StringBuilder();
foreach (PropertyDescriptor descriptor in
TypeDescriptor.GetProperties(htmlAttributes))
{
builder.AppendFormat(" {0}=\"{1}\" ", descriptor.Name,
descriptor.GetValue(htmlAttributes));
}
return builder.ToString();
}
public static MvcHtmlString MyLabel(this HtmlHelper htmlHelper,
string labelText, object htmlAttributes)
{
var attributes = HtmlAttributes(htmlAttributes);
return MvcHtmlString.Create(
String.Format("<label for=\"{0}\" {1}>{0}</label",
labelText, attributes.Trim()));
}
}
Then you can add a label to a view in the following manner:
<%: Html.MyLabel("Hello, World!", new { #id = "myLabel" })%>
The generated HTML is:
<label for="Hello, World!" id="myLabel">Hello, World!</label>
For MVC 3 such a helper function is already available:
http://msdn.microsoft.com/en-us/library/gg538318(v=VS.99).aspx
I have a small MVC site that uses the Html.ActionLink helper for a navbar. One thing I would like to change is that the default ActionLink will render out an html link to a page even if that is the current page.
For example, it creates a link like this:
Some title...
even if you're already on /myUrl. It would be nice if it would disable that link and maybe insert a special CSS class to show the currently visited page, like this:
My Url
Some Other Url
This problem must have been encountered before on loads of MVC sites, so I'm curious to know how other people have tackled it.
This seems like a good scenario to roll a custom HTML helper. So let's roll it:
public static class LinkExtensions
{
public static MvcHtmlString MyActionLink(
this HtmlHelper htmlHelper,
string linkText,
string action,
string controller
)
{
var currentAction = htmlHelper.ViewContext.RouteData.GetRequiredString("action");
var currentController = htmlHelper.ViewContext.RouteData.GetRequiredString("controller");
if (action == currentAction && controller == currentController)
{
var anchor = new TagBuilder("a");
anchor.Attributes["href"] = "#";
anchor.AddCssClass("currentPageCSS");
anchor.SetInnerText(linkText);
return MvcHtmlString.Create(anchor.ToString());
}
return htmlHelper.ActionLink(linkText, action, controller);
}
}
and inside your view:
<%= Html.MyActionLink("hello foo", "Index", "Home") %>
<%= Html.MyActionLink("hello bar", "About", "Home") %>
...
and depending on where you are the helper will generate the proper anchor.
Normally in an ASP.NET view one could use the following function to obtain a URL (not an <a>):
Url.Action("Action", "Controller");
However, I cannot find how to do it from a custom HTML helper. I have
public class MyCustomHelper
{
public static string ExtensionMethod(this HtmlHelper helper)
{
}
}
The helper variable has the Action and GenerateLink methods, but they generate <a>’s. I did some digging in the ASP.NET MVC source code, but I could not find a straightforward way.
The problem is that the Url above is a member of the view class and for its instantiation it needs some contexts and route maps (which I don’t want to be dealing with and I’m not supposed to anyway). Alternatively, the instance of the HtmlHelper class has also some context which I assume is either supper of subset of the context information of the Url instance (but again I don’t want to dealing with it).
In summary, I think it is possible but since all ways I could see, involve some manipulation with some more or less internal ASP.NET stuff, I wonder whether there is a better way.
Edit: For instance, one possibility I see would be:
public class MyCustomHelper
{
public static string ExtensionMethod(this HtmlHelper helper)
{
UrlHelper urlHelper = new UrlHelper(helper.ViewContext.RequestContext);
urlHelper.Action("Action", "Controller");
}
}
But it does not seem right. I don't want to be dealing with instances of UrlHelper myself. There must be an easier way.
You can create url helper like this inside html helper extension method:
var urlHelper = new UrlHelper(htmlHelper.ViewContext.RequestContext);
var url = urlHelper.Action("Home", "Index")
You can also get links using UrlHelper public and static class:
UrlHelper.GenerateUrl(null, actionName, controllerName, null, null, null, routeValues, htmlHelper.RouteCollection, htmlHelper.ViewContext.RequestContext, true)
In this example you don't have to create new UrlHelper class what could be a little advantage.
Here is my tiny extenstion method for getting UrlHelper of a HtmlHelper instance :
public static partial class UrlHelperExtensions
{
/// <summary>
/// Gets UrlHelper for the HtmlHelper.
/// </summary>
/// <param name="htmlHelper">The HTML helper.</param>
/// <returns></returns>
public static UrlHelper UrlHelper(this HtmlHelper htmlHelper)
{
if (htmlHelper.ViewContext.Controller is Controller)
return ((Controller)htmlHelper.ViewContext.Controller).Url;
const string itemKey = "HtmlHelper_UrlHelper";
if (htmlHelper.ViewContext.HttpContext.Items[itemKey] == null)
htmlHelper.ViewContext.HttpContext.Items[itemKey] = new UrlHelper(htmlHelper.ViewContext.RequestContext, htmlHelper.RouteCollection);
return (UrlHelper)htmlHelper.ViewContext.HttpContext.Items[itemKey];
}
}
Use it as:
public static MvcHtmlString RenderManagePrintLink(this HtmlHelper helper, )
{
var url = htmlHelper.UrlHelper().RouteUrl('routeName');
//...
}
(I'm posting this ans for reference only)
In ASP.NET MVC is there an equivalent of the Html.ActionLink helper for Img tags?
I have a controller action that outputs a dynamically generated JPEG and I wanted to use the same Lambda expressions to link to it as I do HREFs using ActionLink.
Alternatively, a helper that just gives the URL to a route (again specified using Lambdas) would also be acceptable.
EDIT: I had originally specified that I was using Preview 5, however I see that a Beta has been released. So all-in-all the version number was an unneeded piece of info as I may be upgrading soon :-)
You can use the URL.Action method
<img src="../../Content/Images/add_48.png" />
This question is older, and I just started recently with ASP.NET MVC when the RC was already out, but for those who find this question later like me this might be interesting:
At least in the RC you can use Url.Action() also with anonymous types, the result looks much nicer than the suggestions above, I guess:
<a href="<%= Url.RouteUrl("MyRoute", new { param1 = "bla", param2 = 5 }) %>">
put in <span>whatever</span> you want, also <img src="a.gif" alt="images" />.
</a>
There are many other overloads for RouteUrl as well, of course.
Url.Action() will get you the bare URL for most overloads of Html.ActionLink, but I think that the URL-from-lambda functionality is only available through Html.ActionLink so far. Hopefully they'll add a similar overload to Url.Action at some point.
I used a workaround to place a marker instead of text for ActionLink and then replace it with my image code. Something like this:
<%= Html.ActionLink("__IMAGE_PLACEHOLDER__", "Products").Replace("__IMAGE_PLACEHOLDER__", "<img src=\"" + myImgUrl + "\" />")%>
Not the most elegant solution but it works.
In MVC3, your link would look like this:
<img src="../../Content/Images/add_48.png" />
In ASP.NET MVC Beta, you can use the Html.BuildUrlFromExpression method in the Futures assembly (which is not included in the default ASP.NET MVC install, but is available from CodePlex) to create a link around an image--or any HTML--using the lambda-style ActionLink syntax, like this:
<a href="<%=Html.BuildUrlFromExpression<MyController>(c => c.MyAction())%>">
<%=Html.Image("~/Content/MyImage.gif")%>
</a>
To keep your image links borderless, you'll need to add a CSS rule like this:
img
{
border: none;
}
You can use this control.It behaves like ActionLink.
http://agilefutures.com/index.php/2009/06/actionimage-aspnet-mvc
It's pretty simple to achieve in MVC 2. I have created my own very simple extension method to support Lambda expressions for the Url.Action helper. It requires that you reference MVC 2 Futures.
Here's the code:
using System;
using System.Linq.Expressions;
using System.Web.Mvc;
using System.Web.Routing;
using ExpressionHelperInternal=Microsoft.Web.Mvc.Internal.ExpressionHelper;
namespace Bnv.Bssi.Web.Infrastructure.Helpers
{
public static class UrlExtensions
{
public static string Action<TController>(this UrlHelper helper, Expression<Action<TController>> action) where TController : Controller
{
RouteValueDictionary routeValuesFromExpression = ExpressionHelperInternal.GetRouteValuesFromExpression<TController>(action);
return helper.Action(routeValuesFromExpression["action"].ToString(), routeValuesFromExpression);
}
}
}
This is how you use it:
<img src="<%= Url.Action<YourController>(c => c.YourActionMethod(param1, param2)); %>" />
I know that my post is too late but i wanna share :)
I added new extension method something like this :
public static class ImageExtensions
{
public static MvcHtmlString ImageLink(this HtmlHelper htmlHelper, string imgSrc, string additionalText = null, string actionName = null, string controllerName = null, object routeValues = null, object linkHtmlAttributes = null, object imgHtmlAttributes = null)
{
var urlHelper = ((Controller)htmlHelper.ViewContext.Controller).Url;
var url = "#";
if (!string.IsNullOrEmpty(actionName))
url = urlHelper.Action(actionName, controllerName, routeValues);
var imglink = new TagBuilder("a");
imglink.MergeAttribute("href", url);
imglink.InnerHtml = htmlHelper.Image(imgSrc, imgHtmlAttributes) + " " + additionalText;
linkHtmlAttributes = new RouteValueDictionary(linkHtmlAttributes);
imglink.MergeAttributes((IDictionary<string, object>)linkHtmlAttributes, true);
return MvcHtmlString.Create(imglink.ToString());
}
public static MvcHtmlString Image(this HtmlHelper htmlHelper, string imgSrc, object imgHtmlAttributes = null)
{
var imgTag = new TagBuilder("img");
imgTag.MergeAttribute("src", imgSrc);
if (imgHtmlAttributes != null)
{
imgHtmlAttributes = new RouteValueDictionary(imgHtmlAttributes);
imgTag.MergeAttributes((IDictionary<string, object>)imgHtmlAttributes, true);
}
return MvcHtmlString.Create(imgTag.ToString());
}
}
Hope this helped.
Is Url.Content() what you're looking for?
Give it something like Url.Content("~/path/to/something.jpg") it will turn it into the appropriate path based on the application root.
-Josh
I took the above answers and made a bit of a wrapper extension:
public static MvcHtmlString ActionImageLink(this HtmlHelper helper, string src, string altText, UrlHelper url, string actionName, string controllerName)
{
return ActionImageLink(helper, src, altText, url, actionName, controllerName, null, null);
}
public static MvcHtmlString ActionImageLink(this HtmlHelper helper, string src, string altText, UrlHelper url, string actionName, string controllerName, Dictionary<string, string> linkAttributes, Dictionary<string, string> imageAttributes)
{
return ActionImageLink(helper, src, altText, url, actionName, controllerName, null, linkAttributes, imageAttributes);
}
public static MvcHtmlString ActionImageLink(this HtmlHelper helper, string src, string altText, UrlHelper url, string actionName, string controllerName, dynamic routeValues, Dictionary<string, string> linkAttributes, Dictionary<string, string> imageAttributes)
{
var linkBuilder = new TagBuilder("a");
linkBuilder.MergeAttribute("href", routeValues == null ? url.Action(actionName, controllerName) : url.Action(actionName, controllerName, routeValues));
var imageBuilder = new TagBuilder("img");
imageBuilder.MergeAttribute("src", url.Content(src));
imageBuilder.MergeAttribute("alt", altText);
if (linkAttributes != null)
{
foreach (KeyValuePair<string, string> attribute in linkAttributes)
{
if (!string.IsNullOrWhiteSpace(attribute.Key) && !string.IsNullOrWhiteSpace(attribute.Value))
{
linkBuilder.MergeAttribute(attribute.Key, attribute.Value);
}
}
}
if (imageAttributes != null)
{
foreach (KeyValuePair<string, string> attribute in imageAttributes)
{
if (!string.IsNullOrWhiteSpace(attribute.Key) && !string.IsNullOrWhiteSpace(attribute.Value))
{
imageBuilder.MergeAttribute(attribute.Key, attribute.Value);
}
}
}
linkBuilder.InnerHtml = MvcHtmlString.Create(imageBuilder.ToString(TagRenderMode.SelfClosing)).ToString();
return MvcHtmlString.Create(linkBuilder.ToString());
}
has made it easier for me anyway, hope it helps someone else.
I tried to put the output of the Html.Image into my Html.ImageLink helper.
#(new HtmlString(Html.ActionLink(Html.Image("image.gif").ToString(), "myAction", "MyController").ToString().Replace("<", "<").Replace(">", ">")))
The problem for me is, that the ActionLink name is encoded so I have < instead of <.
I just removed this encoding and the result works for me.
(Is there a better way of doing this instead using replace?)
Adding to the other posts: in my case (asp.net mvc 3) I wanted an image link to act as a language selector so I ended up with:
public static MvcHtmlString ImageLink(this HtmlHelper htmlHelper, string imgSrc, string cultureName, object htmlAttributes, object imgHtmlAttributes, string languageRouteName = "lang", bool strictSelected = false)
{
UrlHelper urlHelper = ((Controller)htmlHelper.ViewContext.Controller).Url;
TagBuilder imgTag = new TagBuilder("img");
imgTag.MergeAttribute("src", imgSrc);
imgTag.MergeAttributes((IDictionary<string, string>)imgHtmlAttributes, true);
var language = htmlHelper.LanguageUrl(cultureName, languageRouteName, strictSelected);
string url = language.Url;
TagBuilder imglink = new TagBuilder("a");
imglink.MergeAttribute("href", url);
imglink.InnerHtml = imgTag.ToString();
imglink.MergeAttributes((IDictionary<string, string>)htmlAttributes, true);
//if the current page already contains the language parameter make sure the corresponding html element is marked
string currentLanguage = htmlHelper.ViewContext.RouteData.GetRequiredString("lang");
if (cultureName.Equals(currentLanguage, StringComparison.InvariantCultureIgnoreCase))
{
imglink.AddCssClass("selectedLanguage");
}
return new MvcHtmlString(imglink.ToString());
}
The internalization support was done via a language route - original source here.
Nice solutions here, but what if you want to have more then just an image in the actionlink? This is how I do it:
#using (Html.BeginForm("Action", "Controler", ajaxOptions))
{
<button type="submit">
<img src="image.png" />
</button>
}
The drawback is that I still have to do a bit of styling on the button-element, but you can put all the html you want in there.
And it works with the Ajax helper as well: https://stackoverflow.com/a/19302438/961139