Evolution of helper in the First Anniversary of ASP. net mvc tutorial

There must be a reason for everything

Like filter, it is used to solve the problem of unified execution before or after a type of action.Code.

Helper is generated to facilitate view development.

Next we will solve several problems to see how helper evolved.

Start

Question: How do I write a super connection in view to connect to the home page?

This seems to be a good answer:

 
<A Href="/Home/Index">Homepage</A>
 

 

Cheng

In fact, the method above cannot be called is actually the best. Without calling any method, the problem is solved only with pure HTML.

But what if the route rule changes? Just like the original

Routes. maproute ("Default","{Controller}/{action}/{ID}",New{Controller ="Home", Action ="Index", Id =""});
 

Changed

 
Routes. maproute ("Default","{Controller}/ingress action=.htm",New{Controller ="Home", Action ="Index"});
 

 

The extension has changed. If you press the previous answer, the connection will be changed

<A Href="/Home/index.htm">Homepage</A>
 

 

If there are many references to this route rule in the project, such batch changes will surely be exhausting and prone to errors.

What should we do?

So we need to use urlhelper

 
<A Href="<% = URL. Action ("Index","Home") %>"> Homepage</A>
 

 
In this way, the correct address will be obtained when the route rule changes.
 

Transfer

The above method enables the URL to cope with changes, but there is another problem: href = "<% = %>" this method is difficult to intelligently perceive and debug in, therefore, a good debugging method is required, so the initial htmlhelper is generated.

 
<%= Html. actionlink ("Homepage", "Index", "home ")%>
 

 

In this way, you can easily perceive and debug the code, and the code is clean.

 

End

The above is a simple description of why helper appears. I hope my new friends who are learning ASP. NET MVC will be helpful.

 

ASP. net mvc Framework Series