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[英]How to find the Parent of a CustomControl from inside the CustomControl
[英]How to Use UserControl Inside CustomControl?
我正在开发自定义GridView控件。在表头中有选择列表,就像excel一样。 像过滤器一样出色,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的用户控件的控件。 现在,当我想在自定义控件中使用该用户控件时。 我使用此代码:
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,我收到错误消息,因为System.Web.dll中发生了类型为'System.Web.HttpException'的异常,但未在用户代码中处理。其他信息:文件'/AADQuickCustomFilter.ascx'不存在。
因此,请帮助我,问题出在哪里。 我做错了什么? 谢谢专家
这是答案。 首先,我创建一个类来注册ascx文件作为如下代码的嵌入资源:
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;
}
}
}
然后像这样覆盖您的自定义控件的承包商:
public AADExcelFilterGridView() : base()
{System.Web.Hosting.HostingEnvironment.RegisterVirtualPathProvider(new AssemblyResourceProvider(ResourcePrefix));
}
接着
static string mResourcePrefix = "EmbeddedWebResource";
public static string ResourcePrefix
{
get
{
return mResourcePrefix;
}
set
{
mResourcePrefix = value;
}
}
现在,只需将用户控件添加到您的自定义控件渲染中,就像上面这样:
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);
}
这就是您所拥有的,希望对您有用。 感谢专家们的好评。
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