学步园

两者都可以输出一个Partial视图；其区别如下：
1. Partial有返回值(MvcHtmlString)；RenderPartial没有返回值(Void)。
　
  定义
 1 //PartialExtensions.Partial 方法 (HtmlHelper, String)
 2 public static MvcHtmlString Partial(
 3     this HtmlHelper htmlHelper,
 4     string partialViewName
 5 )
 6
 7 //RenderPartialExtensions.RenderPartial 方法 (HtmlHelper, String)
 8 public static void RenderPartial(
 9     this HtmlHelper htmlHelper,
10     string partialViewName
11 )

 
2. Partial输出到临时变量StringWriter ；RenderPartial输出到HtmlHelper.ViewContext.Writer上（即直接输出到Response)。
  Html.Partial内部实现www.2cto.com
public static MvcHtmlString Partial(this HtmlHelper htmlHelper, string partialViewName)
{
    return htmlHelper.Partial(partialViewName, null, htmlHelper.ViewData);
}

public static MvcHtmlString Partial(this HtmlHelper htmlHelper, string partialViewName, object model, ViewDataDictionary viewData)
{
    using (StringWriter writer = new StringWriter(CultureInfo.CurrentCulture))
    {
        htmlHelper.RenderPartialInternal(partialViewName, viewData, model, writer, ViewEngines.Engines);
        return MvcHtmlString.Create(writer.ToString());
    }
}
 

 
  Html.RenderPartial内部实现
1 public static void RenderPartial(this HtmlHelper htmlHelper, string partialViewName)
2 {
3     htmlHelper.RenderPartialInternal(partialViewName, htmlHelper.ViewData, null, htmlHelper.ViewContext.Writer, ViewEngines.Engines);
4 }

 
3. 在Razor视图中语法不一样：
  语法
1 @Html.Partial("PartialViewName")
2
3 @{ Html.RenderPartial("PartialViewName"); }