Asp. Net MVC's custom Extension Method for class HtmlHelper and how to call

C # There have been a lot of articles about the extension method since the extension method has been released for a long time. I will not introduce it here. If you do not understand it, you can refer to Baidu or google. There are also a lot of explanations in the garden.

You can see that this is the three overload methods for TextBoxFor in Microsoft MVC. We can also customize the extension for TextBoxFor (as long as we can implement the style we want), so it is much easier to call.

Now, implement one by yourself.

        public static MvcHtmlString TextBoxFor<TModel>(this HtmlHelper<TModel> htmlHelper, Expression<Func<TModel, DateTime>> expression)        {            return htmlHelper.TextBoxFor(expression, new { @class = "date" });        }

Then we can see that this strong text will be selectively bound to date fields when it is bound to the Model. It does not conflict with the built-in system, because although the method names are the same, but the parameter types are not the same, you can pay attention when you expand it yourself.
Let's call it.

We can see that the three reloads have now become four, and this is exactly our custom extension.

Of course we should reference it before calling it. Here we provide three methods for reference:

First, you can reference the page in the corresponding View to @ using namespace.

Type 2: You can configure it in web. config, so you do not need to reference it in the view.

<Configuration> <system. web> <pages> <namespaces> <add namespace = "namespace name"/> </namespaces> </pages> </system. web> </configuration>

Third: Let's take a look at the namespace System where the built-in methods are located. web. mvc. html, and then change the namespace of our custom extension method to this, so that no configuration or reference is required.
Of course there may be other methods.