zoukankan      html  css  js  c++  java
  • RazorExtensions Templated Razor Delegates

    原文发布时间为:2011-04-27 —— 来源于本人的百度文章 [由搬家工具导入]

    Templated Razor Delegates

    David Fowler turned me on to a really cool feature of Razor I hadn’t realized made it into 1.0, Templated Razor Delegates. What’s that? I’ll let the code do the speaking.

    @{
    Func<dynamic, object> b = @<strong>@item</strong>;
    }
    <span>This sentence is @b("In Bold").</span>

    That could come in handy if you have friends who’ll jump on your case for using the bold tag instead of the strong tag because it’s “not semantic”. Yeah, I’m looking at you Damian . I mean, don’t both words signify being forceful? I digress.

    Note that the delegate that’s generated is a Func<T, HelperResult>. Also, the @item parameter is a special magic parameter. These delegates are only allowed one such parameter, but the template can call into that parameter as many times as it needs.

    The example I showed is pretty trivial. I know what you’re thinking. Why not use a helper? Show me an example where this is really useful. Ok, you got it!

    Suppose I wrote this really cool HTML helper method for generating any kind of list.

    publicstaticclassRazorExtensions {
    publicstaticHelperResult List<T>(thisIEnumerable<T> items,
    Func<T, HelperResult> template) {
    returnnewHelperResult(writer => {
    foreach(var iteminitems) {
    template(item).WriteTo(writer);
    }
    });
    }
    }

    This List method accepts a templated Razor delegate, so we can call it like so.

    @{
    var items = new[] { "one", "two", "three" };
    }

    <ul>
    @items.List(@<li>@item</li>)
    </ul>

    As I mentioned earlier, notice that the argument to this method, @<li>@item</li> is automatically converted into a Func<dynamic, HelperResult> which is what our method requires.

    Now this List method is very reusable. Let’s use it to generate a table of comic books.

    @{
    var comics = new[] {
    new ComicBook {Title = "Groo", Publisher = "Dark Horse Comics"},
    new ComicBook {Title = "Spiderman", Publisher = "Marvel"}
    };
    }

    <table>
    @comics.List(
    @<tr>
    <td>@item.Title</td>
    <td>@item.Publisher</td>
    </tr>)
    </table>

    This feature was originally implemented to support the WebGrid helper method, but I’m sure you’ll think of other creative ways to take advantage of it.

    If you’re interested in how this feature works under the covers, check out this blog post by Andrew Nurse.

    http://haacked.com/archive/2011/02/27/templated-razor-delegates.aspx

  • 相关阅读:
    信令基本概念
    CMMI
    关于OpenDataSource, OpenRowSet
    冒泡排序
    使用Sqlldr向oracle导入数据
    PowerDesigner生成sql和反向工程生成ER图的问题
    2021.1.4 学习总结
    12天 —— 关于生活与目标的思考【2020.8.5~2020.8.17】
    大一暑假学习总结(七)【2020.7.28~2020.8.4】
    学习:用javascript增加、删除行(转)
  • 原文地址:https://www.cnblogs.com/handboy/p/7163978.html
Copyright © 2011-2022 走看看