通过VirtualPathProvider使用嵌入资源

VirtualPathProvider类，提供了一组方法，使 Web 应用程序可以从虚拟文件系统中检索资源。

参见MSDN：http://msdn.microsoft.com/zh-cn/library/system.web.hosting.virtualpathprovider.aspx

 

遇到这样一个需求，要将.ascx作为嵌入资源放到一个Library项目中，在Web App中需要可以使用。

 

上网查找后发现，VirtualPathProvider类可以实现这个目的。

 

步骤一：

通过继承VirtualPathProvider类，实现自己的AssemblyResourceVirtualPathProvider，用来为Assembly中的Resource提供支持。

 

    public class AssemblyResourceVirtualPathProvider : System.Web.Hosting.VirtualPathProvider
    {
        /// <summary>
        /// AssemblyPath与VirtualPath映射
        /// </summary>
        private string _VirtualPath;
        private string _AssemblyPath;

        private string VirtualPath { get { return _VirtualPath; } }
        private string AssemblyPath { get { return _AssemblyPath; } }

        public AssemblyResourceVirtualPathProvider(string virtualPath, string assemblyPath)
        {
            _VirtualPath = "~/" + virtualPath;
            _AssemblyPath = assemblyPath;
        }

        /// <summary>
        /// 是否是AssemblyResource类型的VirtualPath
        /// </summary>
        /// <param name="virtualPath">virtualPath</param>
        /// <returns></returns>
        private bool IsAssemblyResourceVirtualPath(string virtualPath)
        {
            string path = VirtualPathUtility.ToAppRelative(virtualPath);
            return path.StartsWith(VirtualPath, StringComparison.InvariantCultureIgnoreCase);
        }

        /// <summary>
        /// 获取virtualPath对应Assembly内的ResourceName
        /// </summary>
        /// <param name="virtualPath">virtualPath</param>
        /// <returns></returns>
        private string GetResourceName(string virtualPath)
        {
            return VirtualPathUtility.GetFileName(virtualPath);
        }

        #region override

        /// <summary>
        /// 获取VirtualFile
        /// </summary>
        /// <param name="virtualPath"></param>
        /// <returns></returns>
        public override VirtualFile GetFile(string virtualPath)
        {
            if (IsAssemblyResourceVirtualPath(virtualPath))
            {
                string resourceName = this.GetResourceName(virtualPath);
                return new AssemblyResourceVirtualFile(virtualPath, AssemblyPath, resourceName);
            }
            else
            {
                return Previous.GetFile(virtualPath);
            }
        }

        /// <summary>
        /// virtualPath指定的文件是否存在。
        /// </summary>
        /// <param name="virtualPath"></param>
        /// <returns></returns>
        public override bool FileExists(string virtualPath)
        {
            if (IsAssemblyResourceVirtualPath(virtualPath))
            {
                //return true;
                Assembly assembly = Assembly.LoadFrom(AssemblyPath);
                if (assembly != null)
                {
                    string resourceName = this.GetResourceName(virtualPath);
                    return (assembly.GetManifestResourceInfo(resourceName) != null);
                }
                return false;
            }
            else
            {
                return Previous.FileExists(virtualPath);
            }
        }

        public override bool DirectoryExists(string virtualDir)
        {
            if (IsAssemblyResourceVirtualPath(virtualDir))
            {
                return true;
            }
            else
            {
                return Previous.DirectoryExists(virtualDir);
            }
        }

        public override string GetFileHash(string virtualPath, IEnumerable virtualPathDependencies)
        {
            return null;

            //HashCodeCombiner combiner = new HashCodeCombiner();
            //foreach (string str in virtualPathDependencies)
            //{
            //    string fileName = HostingEnvironment.MapPathInternal(str);
            //    combiner.AddFile(fileName);
            //}
            //return combiner.CombinedHashString;
        }

        public override CacheDependency GetCacheDependency(string virtualPath, IEnumerable virtualPathDependencies, DateTime utcStart)
        {
            return null;

            //System.Collections.Specialized.StringCollection fullPathDependencies = null;

            //// Get the full path to all dependencies.
            //foreach (string virtualDependency in virtualPathDependencies)
            //{
            //    if (fullPathDependencies == null)
            //        fullPathDependencies = new System.Collections.Specialized.StringCollection();

            //    fullPathDependencies.Add(virtualDependency);
            //}
            //if (fullPathDependencies == null)
            //    return null;

            //// Copy the list of full-path dependencies into an array.
            //string[] fullPathDependenciesArray = new string[fullPathDependencies.Count];
            //fullPathDependencies.CopyTo(fullPathDependenciesArray, 0);
            //// Copy the virtual path into an array.
            //string[] virtualPathArray = new string[1];
            //virtualPathArray[0] = virtualPath;

            //return new CacheDependency(virtualPathArray, fullPathDependenciesArray, utcStart);
        }

        //public override string CombineVirtualPaths(string basePath, string relativePath)
        //{
        //    if (IsAssemblyResourceVirtualPath(basePath))
        //    {
        //        return null;
        //    }
        //    else
        //    {
        //        return Previous.CombineVirtualPaths(basePath, relativePath);
        //    }
        //}

        //public override System.Runtime.Remoting.ObjRef CreateObjRef(Type requestedType)
        //{
        //    return Previous.CreateObjRef(requestedType);
        //}

        //public override string GetCacheKey(string virtualPath)
        //{
        //    if (IsAssemblyResourceVirtualPath(virtualPath))
        //    {
        //        return null;
        //    }
        //    else
        //    {
        //        return Previous.GetCacheKey(virtualPath);
        //    }
        //}
        #endregion
    }

步骤二：

通过继承VirtualFile类，实现AssemblyResourceVirtualPathProvider的AssemblyResourceVirtualFile，用来提供Resource的Open。

 

    public class AssemblyResourceVirtualFile : VirtualFile
    {
        private string AssemblyPath;
        private string ResourceName;

        public AssemblyResourceVirtualFile(string virtualPath, string assemblyPath, string resourceName)
            : base(virtualPath)
        {
            AssemblyPath = assemblyPath;// Path.Combine(HttpRuntime.BinDirectory, assemblyPath);
            ResourceName = resourceName;
        }

        public override System.IO.Stream Open()
        {
            Assembly assembly = Assembly.LoadFrom(AssemblyPath);
            if (assembly != null)
            {
                return assembly.GetManifestResourceStream(ResourceName);
            }
            return null;
        }
    }

步骤三：

在Global.asax中注册VirtualPathProvider。

 

        protected void Application_Start(object sender, EventArgs e)
        {
            string assemblyPath = "WebControlLibrary.dll";
            assemblyPath = Path.Combine(HttpRuntime.BinDirectory, assemblyPath);
            AssemblyResourceVirtualPathProvider provider = new AssemblyResourceVirtualPathProvider("WebControlDemo", assemblyPath);

            //按链表方式链接注册的VirtualPathProvider。
            HostingEnvironment.RegisterVirtualPathProvider(provider);
        }

步骤四：

创建Library项目，添加Web User Control，将.ascx文件为嵌入资源。

步骤五：

在Web App的页面中使用Web User Control。

        protected override void OnInit(EventArgs e)
        {
            //LoadControl中获取对程序集内资源
            //当然，可以在aspx中使用：
            //<%@ Register Src="WebControlDemo/WebControlLibrary.WebUserControl.ascx" TagName="WebUserControl" TagPrefix="uc1" %>
            //<uc1:WebUserControl id="WebUserControl1_1" runat="server"/>
            WebUserControl1 = this.LoadControl("WebControlDemo/WebControlLibrary.WebUserControl.ascx") as WebUserControl;
            SubWebUserControl1 = this.LoadControl("WebControlDemo/WebControlLibrary.SubDirectory.SubWebUserControl.ascx") as SubWebUserControl;
            this.form1.Controls.Add(WebUserControl1);
            this.form1.Controls.Add(SubWebUserControl1);
            base.OnInit(e);
        }

结束语：

通过嵌入资源的联想，可以将JS文件作为嵌入资源，同样可以通过VirtualPathProvider提供访问支持。

 

            //获取对程序集内资源的 URL 引用 的 虚拟路径方法
            //当然，可以在aspx中使用：<script language="javascript" src="WebControlDemo/WebControlLibrary.VirtualPathProvider.js"></script>
            if (!this.ClientScript.IsClientScriptIncludeRegistered(GetType(), "JS By VirtualPathProvider"))
            {
                string webUrl = "WebControlDemo/WebControlLibrary.VirtualPathProvider.js";
                this.ClientScript.RegisterClientScriptInclude(GetType(), "JS By VirtualPathProvider", webUrl);
            }

            //获取对程序集内资源的 URL 引用 的 一般方法
            if (!this.ClientScript.IsClientScriptIncludeRegistered(GetType(), "JS By WebResourceUrl"))
            {
                string webUrl = Page.ClientScript.GetWebResourceUrl(new WebUserControl().GetType(), "WebControlLibrary.WebResourceUrl.js");
                this.ClientScript.RegisterClientScriptInclude(GetType(), "JS By WebResourceUrl", webUrl);
            }

 代码示例：https://files.cnblogs.com/xujiaoxiang/WebDemo.zip