Html.Include(relativeVirtualPath) 扩展方法
出于文档目的，我想包含这样的文件（将文件的内容放在
标记中）。
为此，我添加了一个 HtmlHelperExtension 方法，该方法采用相对虚拟路径（不必是绝对虚拟路径）和一个可选的布尔值来指示您是否希望对内容进行 html 编码，默认情况下我方法确实如此，因为我主要使用它来显示代码。
让这段代码工作的真正关键是使用VirtualPathUtility 和WebPageBase。示例：
// Assume we are dealing with Razor as WebPageBase is the base page for razor.
// Making this assumption we can get the virtual path of the view currently
// executing (will return partial view virtual path or primary view virtual
// path just depending on what is executing).
var virtualDirectory = VirtualPathUtility.GetDirectory(
((WebPageBase)htmlHelper.ViewDataContainer).VirtualPath);
完整的 HtmlHelper 扩展代码：
public static class HtmlHelperExtensions
{
private static readonly IEnumerable<string> IncludeFileSupportedExtensions = new String[]
{
".resource",
".cshtml",
".vbhtml",
};
public static IHtmlString IncludeFile(
this HtmlHelper htmlHelper,
string virtualFilePath,
bool htmlEncode = true)
{
var virtualDirectory = VirtualPathUtility.GetDirectory(
((WebPageBase)htmlHelper.ViewDataContainer).VirtualPath);
var fullVirtualPath = VirtualPathUtility.Combine(
virtualDirectory, virtualFilePath);
var filePath = htmlHelper.ViewContext.HttpContext.Server.MapPath(
fullVirtualPath);
if (File.Exists(filePath))
{
return GetHtmlString(File.ReadAllText(filePath), htmlEncode);
}
foreach (var includeFileExtension in IncludeFileSupportedExtensions)
{
var filePathWithExtension = filePath + includeFileExtension;
if (File.Exists(filePathWithExtension))
{
return GetHtmlString(File.ReadAllText(filePathWithExtension), htmlEncode);
}
}
throw new ArgumentException(string.Format(
@"Could not find path for ""{0}"".
Virtual Directory: ""{1}""
Full Virtual Path: ""{2}""
File Path: ""{3}""",
virtualFilePath, virtualDirectory, fullVirtualPath, filePath));
}
private static IHtmlString GetHtmlString(string str, bool htmlEncode)
{
return htmlEncode
? new HtmlString(HttpUtility.HtmlEncode(str))
: new HtmlString(str);
}
}