NopCommerce的页面展示

MVC架构，首先”急功近利“选择V下手，在路由中可以看到路由配置中的View，找到首页View

Nop.Web\Views\Home\Index.cshtml

1. @{
2. Layout = "~/Views/Shared/_ColumnsThree.cshtml";
3. }
4. <div class="page home-page">
5. <div class="page-body">
6. @Html.Widget("home_page_top")
7. @Html.Action("TopicBlock", "Topic", new { systemName = "HomePageText" })
8. @Html.Action("HomepageCategories", "Catalog")
9. @Html.Action("HomepageProducts", "Product")
10. @Html.Action("HomepageBestSellers", "Product")
11. @Html.Action("HomePageNews", "News")
12. @Html.Action("HomePagePolls", "Poll")
13. @Html.Widget("home_page_bottom")
14. </div>
15. </div>

页面分布局及内容分块，在asp.net MVC中常用的方法是share文件夹中的布局视图

1. Layout = "~/Views/Shared/_ColumnsThree.cshtml";

分块中常采取的办法有Partial视图或是Action，如上的Html.Action("HomepageCategories", "Catalog")

NopCommerce中还实现了Widget部件的方法

它其实是采用HtmlHelper的扩展方法：

 public static mvcHtmlString Widget(this HtmlHelper helper, string widgetZone, object additionalData = null)

1. {
2. return helper.Action("WidgetsByZone", "Widget", new { widgetZone = widgetZone, additionalData = additionalData });
3. }

Widget部件实质又使用Action实现

扩展方法调用的是WidgetController中的WidgetByZone方法，最终返回的一个类型为MvcHtmlString字符串。

WidgetsByZone方法：

1. [ChildActionOnly]
2. public ActionResult WidgetsByZone(string widgetZone, object additionalData = null)
3. {
4. var cacheKey = string.Format(ModelCacheEventConsumer.WIDGET_MODEL_KEY, _storeContext.CurrentStore.Id, widgetZone);
5. var cacheModel = _cacheManager.Get(cacheKey, () =>
6. {
7. //获取部件的Model集合
8. var model = new List<RenderWidgetModel>();
10. var widgets = _widgetService.LoadActiveWidgetsByWidgetZone(widgetZone, _storeContext.CurrentStore.Id);
11. foreach (var widget in widgets)
12. {
13. var widgetModel = new RenderWidgetModel();
15. string actionName;
16. string controllerName;
17. RouteValueDictionary routeValues;
18. widget.GetDisplayWidgetRoute(widgetZone, out actionName, out controllerName, out routeValues);
19. widgetModel.ActionName = actionName;
20. widgetModel.ControllerName = controllerName;
21. widgetModel.RouteValues = routeValues;
23. model.Add(widgetModel);
24. }
25. return model;
26. });
28. //no data?
29. if (cacheModel.Count == 0)
30. return Content("");
32. //"RouteValues" property of widget models depends on "additionalData".
33. //We need to clone the cached model before modifications (the updated one should not be cached)
34. var clonedModel = new List<RenderWidgetModel>();
35. foreach (var widgetModel in cacheModel)
36. {
37. var clonedWidgetModel = new RenderWidgetModel();
38. clonedWidgetModel.ActionName = widgetModel.ActionName;
39. clonedWidgetModel.ControllerName = widgetModel.ControllerName;
40. if (widgetModel.RouteValues != null)
41. clonedWidgetModel.RouteValues = new RouteValueDictionary(widgetModel.RouteValues);
43. if (additionalData != null)
44. {
45. if (clonedWidgetModel.RouteValues == null)
46. clonedWidgetModel.RouteValues = new RouteValueDictionary();
47. clonedWidgetModel.RouteValues.Add("additionalData", additionalData);
48. }
50. clonedModel.Add(clonedWidgetModel);
51. }
53. return PartialView(clonedModel);
54. }

这个Action对应的视图Nop.Web\Views\Widget\WidgetsByZone.cshtml

 @model List<RenderWidgetModel>

1. @using Nop.Web.Models.Cms;
2. @foreach (var widget in Model)
3. {
4. @Html.Action(widget.ActionName, widget.ControllerName, widget.RouteValues)
5. }

可以看出，部件可以再包含部件或部件列

部件本身也是MVC模式，其M的实现为WidgetService

在WidgetController中的Action方法WidgetsByZone中我们可以看到里面最终调用WidgetService的方法LoadActiveWidgetsByWidgetZone并把结果缓存起来，而LoadActiveWidgetsByWidgetZone返回是一个类型IWidgetPlugin部件插件集合IList<IWidgetPlugin>。

 public virtual IList<IWidgetPlugin> LoadActiveWidgetsByWidgetZone(string widgetZone, int storeId = 0)

1. {
2. if (String.IsNullOrWhiteSpace(widgetZone))
3. return new List<IWidgetPlugin>();
5. return LoadActiveWidgets(storeId)
6. .Where(x => x.GetWidgetZones().Contains(widgetZone, StringComparer.InvariantCultureIgnoreCase))
7. .ToList();
8. }

1. public virtual IList<IWidgetPlugin> LoadAllWidgets(int storeId = 0)
2. {
3. return _pluginFinder.GetPlugins<IWidgetPlugin>(storeId: storeId).ToList();