Is it possible to detect a route value in a view?
Such as /pages/create/1 and I want to check to see if 1 is there?
Basically, I want to render a different partial view based on this value though I'm fairly sure this is probably not the best way to go about what I'm trying to achieve.
On a side note, instead of doing the above is it possible for me to be able to change what partial views are rendered in a view based on a value from within my controller?
ViewContext.RouteData.Values["whatever"]
You can inspect a RouteData object through ViewPage.ViewContext.RouteData. Then check for values using something like
string areaname = routeData.Values["area"] as string;
string controllername = routeData.Values["controller"] as string;
string actionname = routeData.Values["action"] as string;
string id = routeData.Values["id"] as string;
If you find that you want to inspect these values in the controller instead, you can access them using ControllerBase.ControllerContext.RouteData. Something similar applies for action filters etc.
Other answers are correct, but thought i'd address your last sentence:
On a side note, instead of doing the above is it possible for me to be able to change what partial views are rendered in a view based on a value from within my controller?
Well partial view's are rendered in the View itself (unless calling from JavaScript and binding directly to DOM) with the following code:
<%: Html.RenderPartial("SomePartial") %>
So to prevent "code soup" (if statements) in your view, you use a HTML helper which calls through to RenderPartial after inspecting the ViewContext:
public static string RenderCustomPartial(this HtmlHelper helper, RouteData rd)
{
string partialName;
if (rd.Values["SomeParam"] == 1)
partialName = "PartialOneName";
else
partialName = "PartialTwoName";
return helper.RenderPartial(partialName);
}
And then in the View:
<%: Html.RenderCustomPartial(ViewContext.RouteData) %>
You could make some mods to the above - like access the route data directly in the extension, pass through the model to bind in the partial, etc - but you get the idea.
Alternatively you could do the above IF statement in your controller, and stuff the partial view name in the ViewData, then use that in the regular RenderPartial call in your View.
Whatever floats your boat. :)
Related
I have the requirement to use Html.RenderAction like you would in ASP.NET MVC.
For instance I have a Home Page with News and Products on.
I would like to do for instance
#Html.RenderAction("/api/products/featured")
Which would start a new service call and output the template to the html stream.
Is this possible using ServiceStack Razor and if so how do I accomplish it?
The PartialExamples.cshtml test page shows different examples of rendering a razor view inside a page, e.g:
Using the new RenderToAction() method which lets you execute a Service and it's rendered partial view with a route and QueryString, e.g:
#Html.RenderAction("/products/1")
This also takes an optional view name if you want a different view than the default:
#Html.RenderAction("/products/1", "CustomProductView")
There's also the normal Html.Partial() to specify which view and model you want to render in the page, e.g:
#Html.Partial("GetProduct",
base.ExecuteService<ProductService>(s => s.Any(new GetProduct { Id = 1 })))
ExecuteService is simply a wrapper around the equivalent ResolveService in a using statement, i.e:
#{
Response response = null;
using (var service = base.ResolveService<ProductService>())
{
response = service.Any(new GetProduct { Id = 1 });
}
}
#Html.Partial("GetProduct", response)
The new RenderToAction() method in Razor Views was added in v4.0.34+ which is now available on MyGet.
*I may be duplicating my answer or I lost it somehow
Looking at the ServiceStack.Razor.ViewPage class there is an Html property of type ServiceStack.Html.HtmlHelper. I don't see 'RenderAction' as a method (or extension method) on this class so it doesn't appear to be available. There is a 'Partial' method that takes the ViewName and an overload that takes a ViewName and an object. Based on your above comment this doesn't appear to be a useful solution.
If I'm correct about the above, I think you'd need your 'Featured View Template' to pull in the data. Could add soemthing like
{ FeaturedResponse products = new JsonServiceClient("http://localhost").Get<FeaturedResponse>("/api/products/featured"); }
to your template. This would allow you to use the products variable like a Model.
Or, use JavaScript to pull the data into the template. You would have have to use JavaScript to get your data into the HTML elements, though.
You could then render the template using #Html.Partial('Featured')
Hope this helps.
Is there a way by which I can do somethin like this inside a Razor view:
<h1>Normal razor code</h2>
#Html.Action("NormalRazorCode")
#Eval(" #Html.Action(\"RuntimeEval\") ")
Basically a text-to-razor compiler at runtime (that doesnt create a whole new view like RazorEngine does for example).
I think you could assume that the views exist at compile time, and create the actual files at runtime, this way the ViewEngine will work the way it does by default
basically you could create a Html.Eval helper that will create the .cshtml file and after Render it using Html.Action or Html.Partial
I wanted to do something similar; I have model data (under my control) stored in a database, and it would simplify my life if I was able to include HTML helpers in those strings that could be "expanded" when included in a page.
Main motivation was to allow me to re-use existing partial views.
There's no eval function, but you can easily write an extension method that will evaluate methods that you choose to allow in advance. In my case, I want to evaluate calls to #Html.Partial(). The example here is pretty simple - it looks specifically for #Html.Partial("somePartialView") calls and replaces it with the actual partial:
public static IHtmlString ExpandHtmlString(
this HtmlHelper htmlHelper,
String html)
{
if (String.IsNullOrEmpty(html))
return new HtmlString(html);
const String IDENTIFY_PARTIAL = #"#Html.Partial\(""([a-zA-Z0-9\-_]*)""\)";
var partialFinder = new Regex(IDENTIFY_PARTIAL);
var matches = partialFinder.Matches(html);
foreach (Match m in matches) {
var matchedStr = m.Value;
var viewName = m.Groups[1].Value;
var partial = htmlHelper.Partial(viewName);
html = html.Replace(matchedStr, partial.ToHtmlString());
}
return new HtmlString(html);
}
And you call it from your Razor page as so:
#Html.ExpandHtmlString((String)Model.SomeStringField)
You could easily expand on this to to evaluate a set of methods or operators that you decide in advance you will accept.
I have a partialview in _Layout.cshtml that I only want to display for certain urls.
My first thought was in my partial I would use a string as the model #model String .
In the actionmethod that is called I would return this
return PartialView("_MyPartial", new string{Request.FilePath});
In the partial I would have an if block wrapping my outer div that would check the model to see if the url it contained was the url that can display the partial.
I don't like this way because I would have to hardcode the url in if block check
#if( Model == "/Test/Home")
{
<div>
Just an example
</div>
}
What would be the best way to do this?
Thanks
You shouldn't need to use hard coded strings, even if you did the validation within your view like you initially intended.
You can use
Request.Url.AbsolutePath
to get your current url and
Url.Action("action", "controller")
to generate the inacceptable locations.
That said, I would keep your logic determining whether to show the partial view within your controller.
if(showPartialView)
return PartialView("_MyPartial");
else
return new EmptyResult();
Deciding actions based on the request is the responsibility of the Controller. Since the controller chooses the view, why not have it choose the partial as well? Figure out what, if any, partial you want in your controller, and pass it to the view on your view model.
I have a partial view that I want to be generic. According to this question, partial views cannot be generic. So I instead made an HtmlHelper extension that handles the pieces for which I want type-safety, then hands off the rest to a real partial view.
Usually my helper is called on page load, which works fine, but sometimes I want to add a row or something through AJAX. When this happens, the controller cannot use my "partial view" since it does not have access to the HtmlHelper.
Apart from having a partial view with a model of type object, is there anything I can do?
I'm using Razor, if that is important.
A simplified version of what I'm doing:
public static MvcHtmlString DoStuff<T>(this HtmlHelper html, IEnumerable<T> data,
Func<T, ViewModelType> StronglyTypedFn, string PartialName)
{
// the pre- and post-processing for the partial view is complex enough I'd like
// to encapsulate it. But I want the encapsulation to include the safety
// benefits that generics give.
var mappedData = data.Select(StronglyTypedFn);
string htmlData = "";
foreach(var model in mappedData){
htmlData += html.Partial(PartialName, model);
}
htmlData += "some boilerplate footer html";
return htmlData;
}
I realize that in this example I have so few lines of code outside the partial view that it seems pointless to have a helper, but in my real example it is more complex.
Now, in an ajax call I want to return Html.DoStuff(). But I can't, because this requires access to the HtmlHelper, and the helper isn't available inside a controller.
You could just have a simple action method that calls the partial for one model instance
public PartialViewResult Single(string partialName) {
return PartialView(partialName);
}
You could use a View with a Dynamic type instead of object.
But... It seems as if there's some misunderstanding here because the Controller shouldn't try to render the view at all. Could you post the Controller code?
The better option is, IMO, returning a JsonResult for your ajax request and adding the row/rows on client side using JS.
I am writing my first ASP.Net webpage and using MVC.
I have a string that I am building in a partial view with a grid control (DevExpress MVCxGridView). In my partial view I am using a HTML.Hidden helper as shown below.
' Create a hidden variable to pass back a comma-delimited string
Response.Write(Html.Hidden( "exclusionList", Model.ExclusionList))
The value of of this hidden element is assigned in client side javaScript:
exclusionListElement = document.getElementById("exclusionList");
// ...
exclusionString = getExclusionString();
exclusionListElement.value = exclusionString;
This seems to work without problem.
In my controller action method:
<AcceptVerbs( HttpVerbs.Post )> _
Public Function MyPartialCallback(updatedItemList As myModel) As ActionResult
Dim myData As myModel = GetMyModel()
Return PartialView( "MyPartial", myModel.myList )
End Function
The updatedItemList parameter is always nothing and exclusion list exists no where in the Request.Forms.
My questions are:
What is the correct way to use Html.Hidden so that I can access data in a MVC Controller Action method.
Is adding "cargo" variables to Request.Form the best and only way to send data back to a server side MVC Controller Action method? It just seems like twine and duct-tape approach. Is there a more structured approach?
If you need to get the exclusionList variable back, you just need to add a property to your view model that matches that name exactly. Make sure it is of the correct type (string it looks like in this case) and then it should auto populate that property in the view model for you.
And yes, there is no need for the Response.Write call. Instead just use the Html.HiddenFor(...) helper in your view.
Look at the generated HTML. Note down the name attribute of the hidden field. Use this name as action parameter name:
Public Function MyPartialCallback(exclusionList As string)