如何在 CustomControl 中使用 UserControl？

Question

我正在开发自定义 GridView 控件。它在标题中有选择列表，就像 excel 一样。作为像过滤器一样的excel，选项之一是“自定义过滤器”。在这种情况下，我想展示一个我设计为 ascx 的用户控件的小控件。 现在当我想在我的自定义控件中使用该用户控件时。我用这个代码：

 protected override void RenderContents(HtmlTextWriter writer)
    {

        UserControl uc = new UserControl();
        AADQuickCustomFilter CustomFilter = (AADQuickCustomFilter)uc.LoadControl("~/AADQuickCustomFilter.ascx");
        TextWriter tw = new StringWriter();
        HtmlTextWriter hw = new HtmlTextWriter(tw);
        CustomFilter.RenderControl(hw);

        writer.Write(tw.ToString());
        base.RenderContents(writer);
    }

不幸的是，我收到了错误 System.Web.dll 中发生了“System.Web.HttpException”类型的异常，但未在用户代码中处理 附加信息：文件“/AADQuickCustomFilter.ascx”不存在。

所以请帮帮我，问题出在哪里。我做错了什么？ 感谢专家

Answer 1

这是答案。 首先，我创建类以将 ascx 文件注册为嵌入资源，如下代码：

    using System.Web.Hosting;
using System.Web.Caching;
using System.Collections;
using System;
using System.IO;
using System.Web;
using System.Reflection;

namespace AADGridView
{
    public class AssemblyResourceProvider : VirtualPathProvider
    {
        string mResourcePrefix;

        public AssemblyResourceProvider() : this("EmbeddedWebResource")
        {
        }

        public AssemblyResourceProvider(string prefix)
        {
            mResourcePrefix = prefix;
        }

        private bool IsAppResourcePath(string virtualPath)
        {
            String checkPath = VirtualPathUtility.ToAppRelative(virtualPath);
            return checkPath.StartsWith("~/" + mResourcePrefix + "/",
                   StringComparison.InvariantCultureIgnoreCase);
        }

        public override bool FileExists(string virtualPath)
        {
            return (IsAppResourcePath(virtualPath) ||
                    base.FileExists(virtualPath));
        }

        public override VirtualFile GetFile(string virtualPath)
        {
            if (IsAppResourcePath(virtualPath))
                return new AssemblyResourceVirtualFile(virtualPath);
            else
                return base.GetFile(virtualPath);
        }

        public override CacheDependency
               GetCacheDependency(string virtualPath,
               IEnumerable virtualPathDependencies,
               DateTime utcStart)
        {
            if (IsAppResourcePath(virtualPath))
                return null;
            else
                return base.GetCacheDependency(virtualPath,
                       virtualPathDependencies, utcStart);
        }
    }

    class AssemblyResourceVirtualFile : VirtualFile
    {
        string path;

        public AssemblyResourceVirtualFile(string virtualPath) : base(virtualPath)
        {
            path = VirtualPathUtility.ToAppRelative(virtualPath);
        }

        public override Stream Open()
        {
            string[] parts = path.Split('/');
            string assemblyName = parts[2];
            string resourceName = parts[3];
            assemblyName = Path.Combine(HttpRuntime.BinDirectory, assemblyName);
            Assembly assembly = Assembly.LoadFile(assemblyName);
            if (assembly == null) throw new Exception("Failed to load " + assemblyName);
            Stream s = assembly.GetManifestResourceStream(resourceName);
            if (s == null) throw new Exception("Failed to load " + resourceName);
            return s;
        }
    }
}

然后像这样覆盖自定义控件的构造函数：

 public AADExcelFilterGridView() : base()


    {System.Web.Hosting.HostingEnvironment.RegisterVirtualPathProvider(new AssemblyResourceProvider(ResourcePrefix));
}

然后

 static string mResourcePrefix = "EmbeddedWebResource";

    public static string ResourcePrefix
    {
        get
        {
            return mResourcePrefix;
        }

        set
        {
            mResourcePrefix = value;
        }
    }

现在，只需将您的用户控件添加到您的自定义控件渲染中，就像上面一样：

 protected override void RenderContents(HtmlTextWriter writer)
    {

        UserControl uc = new UserControl();
        AADQuickFilter CustomFilter = (AADQuickFilter)uc.LoadControl("~/EmbeddedWebResource/AADGridView.dll/AADGridView.AADQuickFilter.ascx");
        TextWriter tw = new StringWriter();
        HtmlTextWriter hw = new HtmlTextWriter(tw);
        CustomFilter.RenderControl(hw);

        writer.Write(tw.ToString());
        base.RenderContents(writer);
    }

这就是你所得到的，希望有用。 感谢非常好的专家们。