I would like to use renderpartial but I'm not so clear on the way it is used. If I just call render partial then is any model sent to that? I want to use the HTML helpers. Is there any difference between using those in renderpartial and in the main razor view?
If the view actually uses a model and you don't provide any, it just end up having a null Model object (so lots of Null Object Reference Exception).
Just go with
#{ Html.RenderPartial("_partialView", PartialViewModel); }
or:
#Html.Partial("_partialView", PartialViewModel)
The differences between the two are indicated here.
HTH, M.
Related
I am very new in asp.net MVC kindly let me know where is should use partial view and where i should Render Partial view . Thanks in advance
This link might help.
Html.RenderPartial
This method result will be directly written to the HTTP response stream means it used the same TextWriter object as used in the current webpage/template.
This method returns void.
Simple to use and no need to create any action.
RenderPartial method is useful when the displaying data in the partial view is already in the corresponding view model.
For example : In a blog to show comments of an article, we would like to use RenderPartial method since an article information with comments are already populated in the view model.
#{Html.RenderPartial("_Comments");}
This method is faster than Partial method since its result is directly written to the response stream which makes it fast.
Html.Partial
Renders the partial view as an HTML-encoded string.
This method result can be stored in a variable, since it returns string type value.
Simple to use and no need to create any action.
Like RenderPartial method, Partial method is also useful when the displaying data in the partial view is already in the corresponding view model.
For example: In a blog to show comments of an article, you can use Partial method since an article information with comments are already populated in the view model.
#Html.Partial("_Comments")
Both of these helper method are used for rendering partial views
Both have different syntax in razor view #Html.Partial("_student", items) and {Html.RenderPartial("_student", items);}, since render partial return void and the output is written directly to output stream, it has different syntax than Partial.
Syntax in web from view
<%:Html.Partial("_student") %> and <% Html.RenderPartial("_student"); %>
Partial Returns MVCHtmlString, which can be assigned to variables.
Performance wise Render partial is better as it writes directly to output stream.
And of-course you can find a lot of references online and within stack overflow to read
I really don't understand the usage of Html.Action(string,object) its return type is HTMl string so why do we even need it? and whats its relation with partialviewresult ? I have seen some people using #html.action(String actionname,Object routeobject); in any of their view and controller invoked by this method returns a partialviewresult whats that ?
Firstly, HtmlString represents an HTML-encoded string that should not be encoded again. HtmlString Class
There is a answer that I believe is good from this question:
#Html.Action and #Html.RenderAction are used when your partial view model are independent from parent model, basically it is used when you want to display any widget type content on page. You must create an action method which returns a partial view result while calling the method from view.
More, use Html.Action when you actually need to retrieve additional data from the server to populate the partial view
Please have a look at the documentation for more detailed information.
More questions about the same topic:
How can I use Html.Action?
MVC Html.Partial or Html.Action
Maybe a bit of research before posting a question would be better
I am using MVC 3 w/ Razor and using the new dynamic ViewBag property. I would like to use the ViewBag property with the EditorFor/LabelFor Html helpers but can't figure out the syntax.
The View does have a #model set, but the object I am trying to use is not part of that model. I am aware I can create a ViewModel but that is not what I am after.
Can anyone help?
Controller:
var myModel= _repo.GetModel(id);
var newComment = new Comment();
ViewBag.NewComment = newComment;
return View(myModel);
View:
#model Models.MyModel
#(Html.EditorFor(ViewBag.NewComment.Comment))
I haven't tried it, but this should work I think.
#(EditorFor(m => ViewBag.NewComment)
It is possible to use a Linq-to-SQL syntax, but use a completely different object on the right side.
Not knowing what your Comment Model looks like, my gut reaction would be to just do:
#Html.EditorFor(ViewBag.NewComment)
However, because ViewBag is dynamic, you may need to cast NewComment before you use it, in order to get the EditorFor magic.
#Html.EditorFor(ViewBag.NewComment as Comment)
Update
Strike that, EditorFor can only accept an Expression as a parameter, and that Expression must return a property of the page model. I don't think EditorFor or EditorForModel are going to be of any use to you if you don't want to use a ViewModel. Have you considered switching the roles of whatever it is you're using the Model for, with that of the ViewBag?
If for some reason I need to use ViewData to pass the model into my view I do the following to allow for the Html.DisplayFor() helpers.
In the views code block I cast the ViewData model object to its underlying type
var newCommentModel = ( NewComment )ViewBag.NewComment;
Then I assign the following expression to the helper using the strong-typed reference
#Html.DisplayFor( model => newCommentModel )
The expression tree now contains a strongly-typed model and the DisplayTemplate is correctly displayed.
What is the appropriate way of rendering a child template?
And what's the difference? Both seem to work for me.
And why does #Html.RenderPartial() no longer work?
Html.Partial("MyView")
Renders the "MyView" view to an MvcHtmlString. It follows the standard rules for view lookup (i.e. check current directory, then check the Shared directory).
Html.RenderPartial("MyView")
Does the same as Html.Partial(), except that it writes its output directly to the response stream. This is more efficient, because the view content is not buffered in memory. However, because the method does not return any output, #Html.RenderPartial("MyView") won't work. You have to wrap the call in a code block instead: #{Html.RenderPartial("MyView");}.
RenderPage("MyView.cshtml")
Renders the specified view (identified by path and file name rather than by view name) directly to the response stream, like Html.RenderPartial(). You can supply any model you like to the view by including it as a second parameter
RenderPage("MyView.cshtml", MyModel)
I prefer
#RenderPage("_LayoutHeader.cshtml")
Over
#{ Html.RenderPartial("_LayoutHeader"); }
Only because the syntax is easier and it is more readable. Other than that there doesn't seem to be any differences functionality wise.
EDIT: One advantage of RenderPartial is you don't have to specify the entire path or file extension it will search the common places automatically.
The RenderPartial method doesn’t return HTML markup like most other helper methods. Instead, it writes
content directly to the response stream, which is why we must call it like a complete line of C#, using a semicolon.
This is slightly more efficient than buffering the rendered HTML from the partial view, since it will be written to the
response stream anyway. If you prefer a more consistent syntax, you can use the Html.Partial method, which
does exactly the same as the RenderPartial method, but returns an HTML fragment and can be used as
#Html.Partial("Product", p).
We can also pass model using partial views. #Html.Partial("MyView","MyModel");
#RenderPages()
The above does not work in ASP.NET MVC. It only works in WebPages.
#Html.Partial("_Footer")
You will need to use the above in ASP.NET MVC.
For ASP.NET Core 7. In the Shared folder make partial file then user this following code
<partial name="_NavBar" />
I have an error that I kind of understand, but can't figure out to solve in the right way.
I have a MasterPage, from that MasterPage I call:
<% Html.RenderPartial("Tags"); %>
Tags is a strongly typed view that looks like this:
<%# Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl<IEnumerable<JegManglerEn.Controllers.CategoryCount>>" %>
I return the PartialView like this:
return View("Tags", result);
where result is correct and of type:
List<CategoryCount>
The error is this:
The model item passed into the dictionary is of type 'System.Collections.Generic.List1[JegManglerEn.Item]', but this dictionary requires a model item of type 'System.Collections.Generic.IEnumerable1[JegManglerEn.Controllers.CategoryCount]'.
So the setup is this:
MasterPage loads a View that takes a collection of JegManglerEn.Item AND also tries to load a PartialView that takes a collection of a JegManglerEn.Controllers.CategoryCount...but fails to do so.
I know it has something to do with the RenderPartial method because if I change it to RenderAction it's works great.
If you guys have the answer I get to skip looking at the MVC soruce or startup Reflector.
Thanks!
When you call the single-parameter overload of Html.RenderPartial, you're implicitly passing the entire model of the parent view down to the partial. This doesn't work, as the model types expected by the views do not match.
The simplest way to get RenderPartial working in your context is to create a composite model type that contains both the Tags and the page model data, then call the overload where you pass a part of the parent model to the partial:
Html.RenderPartial("Tags", Model.Tags);
That being said, I think RenderAction is most likely the way to go here, as it makes it easier to avoid duplicate code in your controllers (of course assuming you're loading the tags data in the same way for all pages inheriting from the masterpage in question).
Change the
ViewUserControl<IEnumerable<JegManglerEn.Controllers.CategoryCount>>
to
ViewUserControl<List<JegManglerEn.Controllers.CategoryCount>>