This
question is taken from the book
.NET interview questions by
Shivprasadkoirala
.
Yes, we can create our own custom view engine in MVC. To create our own custom
view engine we need to follow 3 steps:-
Let’
say we want to create a custom view engine where in the user can type a command
like “<DateTime>” and it should display the current date and time.
Step 1
:- We need to create a class
which implements “IView” interface. In this class we should write the logic of
how the view will be rendered in the “render” function. Below is a simple code
snippet for the same.
public class MyCustomView : IView
{
private string
_FolderPath; // Define where our views
are stored
public string FolderPath
{
get { return
_FolderPath; }
set { _FolderPath =
value; }
}
public void
Render(ViewContext viewContext, System.IO.TextWriter writer)
{
// Parsing logic
<dateTime>
// read the view file
string strFileData =
File.ReadAllText(_FolderPath);
// we need to and
replace <datetime> datetime.now value
string strFinal =
strFileData.Replace("<DateTime>", DateTime.Now.ToString());
// this replaced data
has to sent for display
writer.Write(strFinal);
}
}
Step
2 :-
We need to
create a class which inherits from “
VirtualPathProviderViewEngine”
and in this class we need to provide the folder path and the extension of the
view name. For instance for razor the extension is “cshtml” , for aspx the view
extension is “.aspx” , so in the same way for our custom view we need to
provide an extension. Below is how the code looks like. You can see the
“ViewLocationFormats” is set to the “Views” folder and the extension is
“.myview”.
public class MyViewEngineProvider : VirtualPathProviderViewEngine
{
// We will create the
object of Mycustome view
public
MyViewEngineProvider() // constructor
{
// Define the
location of the View file
this.ViewLocationFormats = new string[] { "~/Views/{1}/{0}.myview",
"~/Views/Shared/{0}.myview" }; //location and extension of our views
}
protected override IView
CreateView(ControllerContext controllerContext, string viewPath, string
masterPath)
{
var physicalpath =
controllerContext.HttpContext.Server.MapPath(viewPath);
MyCustomView obj =
new MyCustomView(); // Custom view engine class
obj.FolderPath =
physicalpath; // set the path where the views will be stored
return obj; // returned
this view paresing logic so that it can be registered in the view engine
collection
}
protected override IView
CreatePartialView(ControllerContext controllerContext, string partialPath)
{
var physicalpath =
controllerContext.HttpContext.Server.MapPath(partialPath);
MyCustomView obj =
new MyCustomView(); // Custom view engine class
obj.FolderPath =
physicalpath; // set the path where the views will be stored
return obj; //
returned this view paresing logic so that it can be registered in the view
engine collection
}
}
Step 3:-
We need to register the view in
the custom view collection. The best place to register the custom view engine
in the “ViewEngines” collection is the “global.asax” file. Below is the code
snippet for the same.
protected void Application_Start()
{
// Step3 :- register this object in the view engine
collection
ViewEngines.Engines.Add(new MyViewEngineProvider());
…..
}
Below
is a simple output of the custom view written using the commands defined at the
top.
If you
invoke this view you should see the following output.
MVC ASP.NET
interview question References for further reading:-
·
If you
are new to MVC start MVC ( Model view controller) step by step
from here.
What
is difference between tempdata , view data and view bag. http://dotnetinterviewquestion.wordpress.com/2012/09/27/asp-net-mvc-interview-questions-what-is-the-difference-between-tempdata-viewdata-and-viewbag/
·
In
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