I need to create a custom #Html.Partial() method.
Use Case
I have a .cshtml page where in I have multple sections like below
<!-- EDUCATION -->
#Html.Partial("Templates/Create/Modules/Education")
<!-- JOBS -->
#Html.Partial("Templates/Create/Modules/Jobs")
I want to be able to create a custom .Partial() method. Something on the likes of this
#Html.CustomPartial("Templates/Create/Modules/Jobs", "jobs", "edit")
where in the last two parameters are module id and action type id respectively. Using these values I will make a decision in my CustomPartial what I need to show in the output.
I am not sure how to go about this one. Please advice.
Or if someone can point me to the source code of the Html.Partial that too would be very helpful.
You can already do this using the overload of #Html.Partial() that accepts a ViewDataDictionary
#Html.Partial("Templates/Create/Modules/Jobs", new ViewDataDictionary { { "module", someValue }, {"edit", anotherValue }})
Then in the partial
#if(ViewData["module"] == someValue)
{
// do something
}
else
{
// do something else
}
And if your still interested, here is the source code
Here is what worked for me
public static class CustomHtmlHelpers
{
public static MvcHtmlString RenderModule(this HtmlHelper helper,
string partialViewName,
string moduleName,
string actionType)
{
var isAccessAllowed = _someService.someMethod(userId, moduleName, actionType);
if (isAccessAllowed)
{
return helper.Partial(partialViewName);
}
else
{
return MvcHtmlString.Empty;
}
}
}
#Html.Partial("../Partial_views/_Menu_creation", new ViewDataDictionary { { "Type",
"Menu" }, { "Menu", "Dimensions" }, { "Active", "Yes" }, { "Icon", "icon-1" }, {
"data-hide", "" } })
In partial view
#if (ViewData["Type"] == "Menu")
{
#if (ViewData["Active"] == "Yes")
{
<a data-check='#ViewData["Menu"]' role="button" class="active-menu">
<b class='#ViewData["Icon"]'></b>
<span>#ViewData["Menu"]</span>
</a>
}
else
{
}
}
#if (ViewData["Type"] == "Heading")
{
}
This is working
Related
<div class="form-gridcontrol">
<label>Notes</label>
#Html.CustomTextArea(m => m.Notes)
</div>
In ASP.NET MVC , I have created a custom textarea and inputing/displaying data from the database using a Model.Above is the code where you can see the Notes are getting assigned to #Html.CustomTextArea.
I have a situation where , I need to display a text "Not Applicable" if there is no value in "m.Notes"
How I should right the logic in the above code? Please guide.
There are multiple possible ways for this. One of the way is that you can populate in the controller action from where it is loaded like:
public ActionResult YourActionMethod()
{
............
............
if(String.IsNullOrEmpty(model.Notes))
model.Notes = "Not Applicable";
return View(model);
}
Another way can be to introdcue the backing field on your property and write in it's getter:
private String _notes;
public String Notes
{
get
{
return String.IsNullOrEmpty(_notes) ? "Not Applicable" : _notes;
}
set
{
_notes = value;
}
}
You can try this:
#if (Model.Notes != null)
{
#Html.CustomTextArea(m => m.Notes)
}
else
{
#Html.CustomTextArea( m => m.Notes, new { #Value = "Not Applicable"})
}
edit:this is not working with textarea
else
{
#Html.CustomTextArea(m => m.Notes, new {id="mytextarea"})
<script>
$("#mytextarea").text("Not Applicable")
</script>
}
I got a trick for you :)
I am having problem reading this razor syntax that comes from an existing template.
<div class="#(HasText(columnclass) ? columnclass == "myColumns-1" || columnclass == "myColumns-2" ? "col-md-12" : columnclass == "myColumns-12" ? "col-md-6" : "col-md-12" : "col-md-12")">
Is the above the same as:
#if(HasText(columnclass))
{
if(columnclass == "myColumns-1" || columnclass == "myColumns2")
{
<div class="col-md-12"></div>
}
else if (columnclass == "myColumns-12")
{
<div class="col-md-6"></div>
}
else
{
<div class="col-md-12"></div>
}
}
else
{
<div class="col-md-12"></div>
}
Can the first complex razor syntax instead be used in a html.extension or even a func<>?
You can write a simple Extension -
public static class DivExtensions
{
public static MvcHtmlString Div(this HtmlHelper html, string input)
{
if(String.IsNullOrWhiteSpace(input))
return new MvcHtmlString("<div class=\"col-md-12\"></div>");
if (input == "myColumns-12")
return new MvcHtmlString("<div class=\"col-md-6\"></div>");
return new MvcHtmlString("<div class=\"col-md-12\"></div>");
}
}
usage -
#using MVC.NameSpaceOfExtension
#Html.Div("myColumns-6")
NOTE: I cannot guarantee the logic in my extension method. Please do test it on your side and if there is a problem in logic, then please replace it with your logic.
I need to validate 3 or more input fields (required at lest one). For example I have Email, Fax, Phone.
I require at least ONE to be filled in. I need both server and client 'unobtrusive validation'. please help. I looked into "Compare" method and tried modifying it but no luck. please help.
thanks
You could write a custom attribute:
public class AtLeastOneRequiredAttribute : ValidationAttribute, IClientValidatable
{
private readonly string[] _properties;
public AtLeastOneRequiredAttribute(params string[] properties)
{
_properties = properties;
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
if (_properties == null || _properties.Length < 1)
{
return null;
}
foreach (var property in _properties)
{
var propertyInfo = validationContext.ObjectType.GetProperty(property);
if (propertyInfo == null)
{
return new ValidationResult(string.Format("unknown property {0}", property));
}
var propertyValue = propertyInfo.GetValue(validationContext.ObjectInstance, null);
if (propertyValue is string && !string.IsNullOrEmpty(propertyValue as string))
{
return null;
}
if (propertyValue != null)
{
return null;
}
}
return new ValidationResult(FormatErrorMessage(validationContext.DisplayName));
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var rule = new ModelClientValidationRule
{
ErrorMessage = ErrorMessage,
ValidationType = "atleastonerequired"
};
rule.ValidationParameters["properties"] = string.Join(",", _properties);
yield return rule;
}
}
which could be used to decorate one of your view model properties (the one you want to get highlighted if validation fails):
public class MyViewModel
{
[AtLeastOneRequired("Email", "Fax", "Phone", ErrorMessage = "At least Email, Fax or Phone is required")]
public string Email { get; set; }
public string Fax { get; set; }
public string Phone { get; set; }
}
and then a simple controller:
public class HomeController : Controller
{
public ActionResult Index()
{
var model = new MyViewModel();
return View(model);
}
[HttpPost]
public ActionResult Index(MyViewModel model)
{
return View(model);
}
}
Rendering the following view which will take care of defining the custom client side validator adapter:
#model MyViewModel
<script src="#Url.Content("~/Scripts/jquery.validate.js")" type="text/javascript"></script>
<script src="#Url.Content("~/Scripts/jquery.validate.unobtrusive.js")" type="text/javascript"></script>
<script type="text/javascript">
jQuery.validator.unobtrusive.adapters.add(
'atleastonerequired', ['properties'], function (options) {
options.rules['atleastonerequired'] = options.params;
options.messages['atleastonerequired'] = options.message;
}
);
jQuery.validator.addMethod('atleastonerequired', function (value, element, params) {
var properties = params.properties.split(',');
var values = $.map(properties, function (property, index) {
var val = $('#' + property).val();
return val != '' ? val : null;
});
return values.length > 0;
}, '');
</script>
#using (Html.BeginForm())
{
#Html.ValidationSummary(false)
<div>
#Html.LabelFor(x => x.Email)
#Html.EditorFor(x => x.Email)
</div>
<div>
#Html.LabelFor(x => x.Fax)
#Html.EditorFor(x => x.Fax)
</div>
<div>
#Html.LabelFor(x => x.Phone)
#Html.EditorFor(x => x.Phone)
</div>
<input type="submit" value="OK" />
}
Of course the custom adapter and validator rule should be externalized into a separate javascript file to avoid mixing script with markup.
I spent more than 36 hours why the code did not work for me.. At the end , I found out that in my case , I was not supposed to use the property names in this line of code
[AtLeastOneRequired("Email", "Fax", "Phone", ErrorMessage = "At least Email, Fax or Phone is required")]
But I had to use the HTMl element Ids in place of the property names and it worked like magic.
Posting this here if it might help somebody.
Since you are using MVC 3, take a look at great video Brad Wilson had on mvcConf. There's everything you need to create client + server Unobtrusive Validation
#Darin Dimitrov 's solution is probably the standard of creating a custom validation attribute that works with unobtrusive validation. However, using custom validation attributes for unobtrusive validation have some disadvantages such as:
The custom validation attribute is only attached to one properties, so client validation will not work if there's a change event on the other two inputs.
The error message works fine with ValidationSummary, but if you want to display 1 error message for the whole group (which I think is the norm), it would be nearly impossible.
To avoid the first problem, we can add custom validation attribute to each element in the group, which will cause another problem: we have to validate all elements of the group, instead of stopping at the first invalid group element. And of course, the second problem - separate error messages for each element - still remains.
There's another way to handle client side validation of group of inputs, using groups setting in jquery validator (https://jqueryvalidation.org/validate/#groups). The only problem (and a big one) is that unobtrusive validation doesn't support jquery validation's groups by default, so we have to customize a little bit.
Although this answer is hardly "unobtrusive", in my opinion, it is worth trying to get rid of unnecessary complication of code, if your final goal is to validate a group of inputs while using Microsoft's unobtrusive validator library.
First, because groups settings of default jquery validator is not available in jquery unobtrusive validator, we have to override unobtrusive settings (ref. How can I customize the unobtrusive validation in ASP.NET MVC 3 to match my style?)
$("form").on('submit', function () {
var form = this;
var validator = $(this).data("validator");
if (validator.settings && !validator.settings.submitHandler) {
$.extend(true, validator.settings.rules, validationSettings.rules);
$.extend(true, validator.settings.groups, validationSettings.groups);
initGroups(validator);
var fnErrorReplacement = validator.settings.errorPlacement;
validator.settings.errorPlacement = function (error, element) {
validationSettings.errorPlacement(error, element, fnErrorReplacement, form);
}
validator.settings.submitHandler = formSubmitHandler;
}
});
function formSubmitHandler(form) {
form.submit();
}
After that, override unobtrusive validator's groups, rules and errorPlacement settings.
var validationSettings = {
groups: {
checkboxgroup: "Email Fax Phone"
},
rules: {
Email: {
required: function () {
return validateCheckboxGroup(["#Email", "#Fax", "#Phone"]);
}
},
Fax: {
required: function () {
return validateCheckboxGroup(["#Email", "#Fax", "#Phone"]);
}
},
Phone: {
required: function () {
return validateCheckboxGroup(["#Email", "#Fax", "#Phone"]);
}
}
}
,
errorPlacement: function (error, element, fnUnobtrusive, form) {
switch (element.attr("name")) {
case "Email":
case "Fax":
case "Phone":
onGroupError(error, "CheckBoxGroup", form);
break;
default:
fnUnobtrusive(error, element);
break;
}
}
}
function validateCheckboxGroup(names) {
var result = true;
$.each(names, function (index, value) {
if ($(value).is(":checked")) {
result = false;
}
});
return result;
}
Because unobtrusive validator does not implement groups setting of jquery validator, we need to reuse two functions from the two libraries to: (1).split group names (reusing code from jquery validator) and (2) append error element without remove 'input-validation-error' class (reusing function onError from unobtrusive library).
function initGroups(validators) {
validators.groups = {};
$.each(validators.settings.groups,
function (key, value) {
if (typeof value === "string") {
value = value.split(/\s/);
}
$.each(value,
function (index, name) {
validators.groups[name] = key;
});
});
}
function onGroupError(error, inputElementName, form) {
var container = $(form).find("[data-valmsg-for='" + inputElementName + "']"),
replaceAttrValue = container.attr("data-valmsg-replace"),
replace = replaceAttrValue ? $.parseJSON(replaceAttrValue) !== false : null;
container.removeClass("field-validation-valid").addClass("field-validation-error");
error.data("unobtrusiveContainer", container);
if (replace) {
container.empty();
error.appendTo(container);
}
else {
error.hide();
}
}
Finally, use HtmlExtensions.ValidationMessage to create error span of the checkbox group.
#Html.ValidationMessage("CheckBoxGroup", new { #class = "text-danger" })
The keeping of "input-validation-error" class is necessary, so that jquery validator will validate all 3 elements (Email, Phone, Fax) of checkbox group as a whole, instead of validating one by one. The unobtrusive validation library remove this class by default on function onError, so we have to customize this as shown in function onGroupError above.
I have the following code which is not working as expected. I want to have a retrun from the controller and using alert display the value returned from the controller.
$('#change').dialog({
autoOpen: false,
width: 380,
buttons: {
"Close": function() {
$(this).dialog("close");
},
"Accept": function() {
var test = $("#ChangePasswordForm").submit();
alert(test);
}
}
});
In my controller I want to return a string
[AcceptVerbs(HttpVerbs.Post)]
public string ChangePassword(string Name)
{
var msg = "Cool!";
if (name != null)
return msg;
}
How can I do that?
Your controller needs to return a type that derives from an ActionResult.
If you want to display a simple confirmation message you can add it to the ViewData bag like this:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult ChangePassword(string name)
{
if (!string.IsNullOrEmpty(name))
{
ViewData["msg"] = "Cool";
}
return View();
}
Then, in your view, check for the presence of the value, and display it if it's there:
<% if(ViewData["msg"] != null) { %>
<script type="text/javascript">alert('<%= ViewData["msg"].ToString() %>')</script>
<%} %>
First of all, im assuming you are using an ajax form for this. I also assume you have a or something for putting your text into. All you have to do is set the UpdateTargetId to point at the id of the element you want to update with the text
<%using (Ajax.Form("ChangePasswordForm", new AjaxOptions { UpdateTargetId = "result" })) %>
.
[HttpPost]
public ContentResult ChangePassword(string s)
{
var msg = "Cool!";
if ( s != null ? return Content(msg, "text/plain") : return Content("An error has occured", "text/plain") );
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult ChangePassword(string Name)
{
var msg = "Cool!";
if (name != null)
{
return Content(msg, "text/plain");
}
else
{
return Content("Error...", "text/plain");
}
}
Don't submit the form as that will perform a postback and cause the dialog to be removed.
Instead perform an AJAX post to the Controller Action and return a JsonResult containing the data.
Hook into the success callback from the Ajax request, and call alert passing the data from the Json object.
You'll probably wan't to use a loading mask after clicking submit so the user knows something is going on.
How can dynamic breadcrumbs be achieved with ASP.net MVC?
If you are curious about what breadcrumbs are:
What are breadcrumbs? Well, if you have ever browsed an online store or read posts in a forum, you have likely encountered breadcrumbs. They provide an easy way to see where you are on a site. Sites like Craigslist use breadcrumbs to describe the user's location. Above the listings on each page is something that looks like this:
s.f. bayarea craigslist > city of san francisco > bicycles
EDIT
I realize what is possible with the SiteMapProvider. I am also aware of the providers out there on the net that will let you map sitenodes to controllers and actions.
But, what about when you want a breadcrumb's text to match some dynamic value, like this:
Home > Products > Cars > Toyota
Home > Products > Cars > Chevy
Home > Products > Execution Equipment > Electric Chair
Home > Products > Execution Equipment > Gallows
... where the product categories and the products are records from a database. Some links should be defined statically (Home for sure).
I am trying to figure out how to do this, but I'm sure someone has already done this with ASP.net MVC.
Sitemap's are definitely one way to go... alternatively, you can write one yourself! (of course as long as standard MVC rules are followed)... I just wrote one, I figured I would share here.
#Html.ActionLink("Home", "Index", "Home")
#if(ViewContext.RouteData.Values["controller"].ToString() != "Home") {
#:> #Html.ActionLink(ViewContext.RouteData.Values["controller"].ToString(), "Index", ViewContext.RouteData.Values["controller"].ToString())
}
#if(ViewContext.RouteData.Values["action"].ToString() != "Index"){
#:> #Html.ActionLink(ViewContext.RouteData.Values["action"].ToString(), ViewContext.RouteData.Values["action"].ToString(), ViewContext.RouteData.Values["controller"].ToString())
}
Hopefully someone will find this helpful, this is exactly what I was looking for when I searched SO for MVC breadcrumbs.
ASP.NET 5 (aka ASP.NET Core), MVC Core Solution
In ASP.NET Core, things are further optimized as we don't need to stringify the markup in the extension method.
In ~/Extesions/HtmlExtensions.cs:
using System.Text.RegularExpressions;
using Microsoft.AspNetCore.Html;
using Microsoft.AspNetCore.Mvc.Rendering;
namespace YourProjectNamespace.Extensions
{
public static class HtmlExtensions
{
private static readonly HtmlContentBuilder _emptyBuilder = new HtmlContentBuilder();
public static IHtmlContent BuildBreadcrumbNavigation(this IHtmlHelper helper)
{
if (helper.ViewContext.RouteData.Values["controller"].ToString() == "Home" ||
helper.ViewContext.RouteData.Values["controller"].ToString() == "Account")
{
return _emptyBuilder;
}
string controllerName = helper.ViewContext.RouteData.Values["controller"].ToString();
string actionName = helper.ViewContext.RouteData.Values["action"].ToString();
var breadcrumb = new HtmlContentBuilder()
.AppendHtml("<ol class='breadcrumb'><li>")
.AppendHtml(helper.ActionLink("Home", "Index", "Home"))
.AppendHtml("</li><li>")
.AppendHtml(helper.ActionLink(controllerName.Titleize(),
"Index", controllerName))
.AppendHtml("</li>");
if (helper.ViewContext.RouteData.Values["action"].ToString() != "Index")
{
breadcrumb.AppendHtml("<li>")
.AppendHtml(helper.ActionLink(actionName.Titleize(), actionName, controllerName))
.AppendHtml("</li>");
}
return breadcrumb.AppendHtml("</ol>");
}
}
}
~/Extensions/StringExtensions.cs remains the same as below (scroll down to see the MVC5 version).
In razor view, we don't need Html.Raw, as Razor takes care of escaping when dealing with IHtmlContent:
....
....
<div class="container body-content">
<!-- #region Breadcrumb -->
#Html.BuildBreadcrumbNavigation()
<!-- #endregion -->
#RenderBody()
<hr />
...
...
ASP.NET 4, MVC 5 Solution
=== ORIGINAL / OLD ANSWER BELOW ===
(Expanding on Sean Haddy's answer above)
If you want to make it extension-driven (keeping Views clean), you can do something like:
In ~/Extesions/HtmlExtensions.cs:
(compatible with MVC5 / bootstrap)
using System.Text;
using System.Web.Mvc;
using System.Web.Mvc.Html;
namespace YourProjectNamespace.Extensions
{
public static class HtmlExtensions
{
public static string BuildBreadcrumbNavigation(this HtmlHelper helper)
{
// optional condition: I didn't wanted it to show on home and account controller
if (helper.ViewContext.RouteData.Values["controller"].ToString() == "Home" ||
helper.ViewContext.RouteData.Values["controller"].ToString() == "Account")
{
return string.Empty;
}
StringBuilder breadcrumb = new StringBuilder("<ol class='breadcrumb'><li>").Append(helper.ActionLink("Home", "Index", "Home").ToHtmlString()).Append("</li>");
breadcrumb.Append("<li>");
breadcrumb.Append(helper.ActionLink(helper.ViewContext.RouteData.Values["controller"].ToString().Titleize(),
"Index",
helper.ViewContext.RouteData.Values["controller"].ToString()));
breadcrumb.Append("</li>");
if (helper.ViewContext.RouteData.Values["action"].ToString() != "Index")
{
breadcrumb.Append("<li>");
breadcrumb.Append(helper.ActionLink(helper.ViewContext.RouteData.Values["action"].ToString().Titleize(),
helper.ViewContext.RouteData.Values["action"].ToString(),
helper.ViewContext.RouteData.Values["controller"].ToString()));
breadcrumb.Append("</li>");
}
return breadcrumb.Append("</ol>").ToString();
}
}
}
In ~/Extensions/StringExtensions.cs:
using System.Globalization;
using System.Text.RegularExpressions;
namespace YourProjectNamespace.Extensions
{
public static class StringExtensions
{
public static string Titleize(this string text)
{
return CultureInfo.CurrentCulture.TextInfo.ToTitleCase(text).ToSentenceCase();
}
public static string ToSentenceCase(this string str)
{
return Regex.Replace(str, "[a-z][A-Z]", m => m.Value[0] + " " + char.ToLower(m.Value[1]));
}
}
}
Then use it like (in _Layout.cshtml for example):
....
....
<div class="container body-content">
<!-- #region Breadcrumb -->
#Html.Raw(Html.BuildBreadcrumbNavigation())
<!-- #endregion -->
#RenderBody()
<hr />
...
...
There is a tool to do this on codeplex: http://mvcsitemap.codeplex.com/ [project moved to github]
Edit:
There is a way to derive a SiteMapProvider from a database: http://www.asp.net/Learn/data-access/tutorial-62-cs.aspx
You might be able to modify the mvcsitemap tool to use that to get what you want.
I built this nuget package to solve this problem for myself:
https://www.nuget.org/packages/MvcBreadCrumbs/
You can contribute here if you have ideas for it:
https://github.com/thelarz/MvcBreadCrumbs
For those using ASP.NET Core 2.0 and looking for a more decoupled approach than vulcan's HtmlHelper, I recommend having a look at using a partial view with dependency injection.
Below is a simple implementation which can easily be molded to suit your needs.
The breadcrumb service (./Services/BreadcrumbService.cs):
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using System;
using System.Collections.Generic;
namespace YourNamespace.YourProject
{
public class BreadcrumbService : IViewContextAware
{
IList<Breadcrumb> breadcrumbs;
public void Contextualize(ViewContext viewContext)
{
breadcrumbs = new List<Breadcrumb>();
string area = $"{viewContext.RouteData.Values["area"]}";
string controller = $"{viewContext.RouteData.Values["controller"]}";
string action = $"{viewContext.RouteData.Values["action"]}";
object id = viewContext.RouteData.Values["id"];
string title = $"{viewContext.ViewData["Title"]}";
breadcrumbs.Add(new Breadcrumb(area, controller, action, title, id));
if(!string.Equals(action, "index", StringComparison.OrdinalIgnoreCase))
{
breadcrumbs.Insert(0, new Breadcrumb(area, controller, "index", title));
}
}
public IList<Breadcrumb> GetBreadcrumbs()
{
return breadcrumbs;
}
}
public class Breadcrumb
{
public Breadcrumb(string area, string controller, string action, string title, object id) : this(area, controller, action, title)
{
Id = id;
}
public Breadcrumb(string area, string controller, string action, string title)
{
Area = area;
Controller = controller;
Action = action;
if (string.IsNullOrWhiteSpace(title))
{
Title = Regex.Replace(CultureInfo.CurrentCulture.TextInfo.ToTitleCase(string.Equals(action, "Index", StringComparison.OrdinalIgnoreCase) ? controller : action), "[a-z][A-Z]", m => m.Value[0] + " " + char.ToLower(m.Value[1]));
}
else
{
Title = title;
}
}
public string Area { get; set; }
public string Controller { get; set; }
public string Action { get; set; }
public object Id { get; set; }
public string Title { get; set; }
}
}
Register the service in startup.cs after AddMvc():
public void ConfigureServices(IServiceCollection services)
{
services.AddMvc();
services.AddTransient<BreadcrumbService>();
Create a partial to render the breadcrumbs (~/Views/Shared/Breadcrumbs.cshtml):
#using YourNamespace.YourProject.Services
#inject BreadcrumbService BreadcrumbService
#foreach(var breadcrumb in BreadcrumbService.GetBreadcrumbs())
{
<a asp-area="#breadcrumb.Area" asp-controller="#breadcrumb.Controller" asp-action="#breadcrumb.Action" asp-route-id="#breadcrumb.Id">#breadcrumb.Title</a>
}
At this point, to render the breadcrumbs simply call Html.Partial("Breadcrumbs") or Html.PartialAsync("Breadcrumbs").
Maarten Balliauw's MvcSiteMapProvider worked pretty well for me.
I created a small mvc app to test his provider: MvcSiteMapProvider Test (404)
For whoever is interested, I did an improved version of a HtmlExtension that is also considering Areas and in addition uses Reflection to check if there is a Default controller inside an Area or a Index action inside a Controller:
public static class HtmlExtensions
{
public static MvcHtmlString BuildBreadcrumbNavigation(this HtmlHelper helper)
{
string area = (helper.ViewContext.RouteData.DataTokens["area"] ?? "").ToString();
string controller = helper.ViewContext.RouteData.Values["controller"].ToString();
string action = helper.ViewContext.RouteData.Values["action"].ToString();
// add link to homepage by default
StringBuilder breadcrumb = new StringBuilder(#"
<ol class='breadcrumb'>
<li>" + helper.ActionLink("Homepage", "Index", "Home", new { Area = "" }, new { #class="first" }) + #"</li>");
// add link to area if existing
if (area != "")
{
breadcrumb.Append("<li>");
if (ControllerExistsInArea("Default", area)) // by convention, default Area controller should be named Default
{
breadcrumb.Append(helper.ActionLink(area.AddSpaceOnCaseChange(), "Index", "Default", new { Area = area }, new { #class = "" }));
}
else
{
breadcrumb.Append(area.AddSpaceOnCaseChange());
}
breadcrumb.Append("</li>");
}
// add link to controller Index if different action
if ((controller != "Home" && controller != "Default") && action != "Index")
{
if (ActionExistsInController("Index", controller, area))
{
breadcrumb.Append("<li>");
breadcrumb.Append(helper.ActionLink(controller.AddSpaceOnCaseChange(), "Index", controller, new { Area = area }, new { #class = "" }));
breadcrumb.Append("</li>");
}
}
// add link to action
if ((controller != "Home" && controller != "Default") || action != "Index")
{
breadcrumb.Append("<li>");
//breadcrumb.Append(helper.ActionLink((action.ToLower() == "index") ? controller.AddSpaceOnCaseChange() : action.AddSpaceOnCaseChange(), action, controller, new { Area = area }, new { #class = "" }));
breadcrumb.Append((action.ToLower() == "index") ? controller.AddSpaceOnCaseChange() : action.AddSpaceOnCaseChange());
breadcrumb.Append("</li>");
}
return MvcHtmlString.Create(breadcrumb.Append("</ol>").ToString());
}
public static Type GetControllerType(string controller, string area)
{
string currentAssembly = Assembly.GetExecutingAssembly().GetName().Name;
IEnumerable<Type> controllerTypes = Assembly.GetExecutingAssembly().GetTypes().Where(o => typeof(IController).IsAssignableFrom(o));
string typeFullName = String.Format("{0}.Controllers.{1}Controller", currentAssembly, controller);
if (area != "")
{
typeFullName = String.Format("{0}.Areas.{1}.Controllers.{2}Controller", currentAssembly, area, controller);
}
return controllerTypes.Where(o => o.FullName == typeFullName).FirstOrDefault();
}
public static bool ActionExistsInController(string action, string controller, string area)
{
Type controllerType = GetControllerType(controller, area);
return (controllerType != null && new ReflectedControllerDescriptor(controllerType).GetCanonicalActions().Any(x => x.ActionName == action));
}
public static bool ControllerExistsInArea(string controller, string area)
{
Type controllerType = GetControllerType(controller, area);
return (controllerType != null);
}
public static string AddSpaceOnCaseChange(this string text)
{
if (string.IsNullOrWhiteSpace(text))
return "";
StringBuilder newText = new StringBuilder(text.Length * 2);
newText.Append(text[0]);
for (int i = 1; i < text.Length; i++)
{
if (char.IsUpper(text[i]) && text[i - 1] != ' ')
newText.Append(' ');
newText.Append(text[i]);
}
return newText.ToString();
}
}
If can definitely can be improved (probably does not cover all the possible cases), but it did not failed me until now.