问当前上下文中不存在FileUpload1
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Stack Overflow用户

提问于 2019-03-15 03:57:25

回答 1查看 322关注 0票数 0

我对网页比较陌生，尤其是asp.net/c#。我之所以遵循一个示例，是因为我想创建一个简单的网页，它将列出目录中的文件，并让用户下载列出的文件，其中显示的文件列在目录名下，并使用文件名。我找到了一个pretty good example that does that and a little extra (deleting)。我下载了解决方案，并试图弄清楚如何在visual studio 2015中编辑/运行它，我遵循了这个example which creates an empty mvc project。然后，我右键单击解决方案名称，并添加一个现有文件(下载的解决方案中的CS.aspx.cs文件和web.context )，在系统要求时覆盖VS中的现有web.config。当我构建这个项目时，它缺少GridView1 (在当前上下文中不存在)，所以我添加了这一行

protected GridView GridView1;

这是在gridview1 missing中建议的。

现在我想知道为什么FileUpload1失踪了。我是否需要添加一个

protected FileUpload FileUpload1

变量也是吗？我看到了其他的那个said to add the id to the asp的examples，但我没有他们说要添加它的asp行，也不认为在我下面的例子中他们是在调用它。

这是添加了我添加的Gridview定义的示例中的CS.aspx.cs：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.IO;

public partial class CS : System.Web.UI.Page
{
    protected GridView GridView1;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            string[] filePaths = Directory.GetFiles(Server.MapPath("~/Uploads/"));
            List<ListItem> files = new List<ListItem>();
            foreach (string filePath in filePaths)
            {
                files.Add(new ListItem(Path.GetFileName(filePath), filePath));
            }
            GridView1.DataSource = files;
            GridView1.DataBind();
        }
    }
    protected void UploadFile(object sender, EventArgs e)
    {
        string fileName = Path.GetFileName(FileUpload1.PostedFile.FileName);
        FileUpload1.PostedFile.SaveAs(Server.MapPath("~/Uploads/") + fileName);
        Response.Redirect(Request.Url.AbsoluteUri);
    }
    protected void DownloadFile(object sender, EventArgs e)
    {
        string filePath = (sender as LinkButton).CommandArgument;
        Response.ContentType = ContentType;
        Response.AppendHeader("Content-Disposition", "attachment; filename=" + Path.GetFileName(filePath));
        Response.WriteFile(filePath);
        Response.End();
    }
    protected void DeleteFile(object sender, EventArgs e)
    {
        string filePath = (sender as LinkButton).CommandArgument;
        File.Delete(filePath);
        Response.Redirect(Request.Url.AbsoluteUri);
    }
}

以下是示例中的web.config：

<?xml version="1.0"?>
<configuration>
  <configSections>
    <sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
      <sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
        <section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
        <sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
          <section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="Everywhere"/>
          <section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
          <section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
          <section name="roleService" type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
        </sectionGroup>
      </sectionGroup>
    </sectionGroup>
  </configSections>
  <appSettings/>
  <connectionStrings/>
  <system.web>
    <!-- 
            Visual Basic options:
            Set strict="true" to disallow all data type conversions 
            where data loss can occur. 
            Set explicit="true" to force declaration of all variables.
        -->
    <compilation debug="true" strict="false" explicit="true">
      <assemblies>
        <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
        <add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
        <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
        <add assembly="System.Xml.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
      </assemblies>
    </compilation>
    <!--
          The <authentication> section enables configuration 
          of the security authentication mode used by 
          ASP.NET to identify an incoming user. 
        -->
    <authentication mode="Windows"/>
    <!--
           The <customErrors> section enables configuration 
           of what to do if/when an unhandled error occurs 
           during the execution of a request. Specifically, 
           it enables developers to configure html error pages 
           to be displayed in place of a error stack trace.

           <customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
             <error statusCode="403" redirect="NoAccess.htm" />
             <error statusCode="404" redirect="FileNotFound.htm" />
           </customErrors>
        -->
    <pages>
      <namespaces>
        <clear/>
        <add namespace="System"/>
        <add namespace="System.Collections"/>
        <add namespace="System.Collections.Generic"/>
        <add namespace="System.Collections.Specialized"/>
        <add namespace="System.Configuration"/>
        <add namespace="System.Text"/>
        <add namespace="System.Text.RegularExpressions"/>
        <add namespace="System.Linq"/>
        <add namespace="System.Xml.Linq"/>
        <add namespace="System.Web"/>
        <add namespace="System.Web.Caching"/>
        <add namespace="System.Web.SessionState"/>
        <add namespace="System.Web.Security"/>
        <add namespace="System.Web.Profile"/>
        <add namespace="System.Web.UI"/>
        <add namespace="System.Web.UI.WebControls"/>
        <add namespace="System.Web.UI.WebControls.WebParts"/>
        <add namespace="System.Web.UI.HtmlControls"/>
      </namespaces>
      <controls>
        <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
        <add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      </controls>
    </pages>
    <httpHandlers>
      <remove verb="*" path="*.asmx"/>
      <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validate="false"/>
    </httpHandlers>
    <httpModules>
      <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
    </httpModules>
  </system.web>
  <system.codedom>
    <compilers>
      <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
        <providerOption name="CompilerVersion" value="v3.5"/>
        <providerOption name="WarnAsError" value="false"/>
      </compiler>
      <compiler language="vb;vbs;visualbasic;vbscript" extension=".vb" warningLevel="4" type="Microsoft.VisualBasic.VBCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
        <providerOption name="CompilerVersion" value="v3.5"/>
        <providerOption name="OptionInfer" value="true"/>
        <providerOption name="WarnAsError" value="false"/>
      </compiler>
    </compilers>
  </system.codedom>
  <!-- 
        The system.webServer section is required for running ASP.NET AJAX under Internet
        Information Services 7.0.  It is not necessary for previous version of IIS.
    -->
  <system.webServer>
    <validation validateIntegratedModeConfiguration="false"/>
    <modules>
      <remove name="ScriptModule"/>
      <add name="ScriptModule" preCondition="managedHandler" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
    </modules>
    <handlers>
      <remove name="WebServiceHandlerFactory-Integrated"/>
      <remove name="ScriptHandlerFactory"/>
      <remove name="ScriptHandlerFactoryAppServices"/>
      <remove name="ScriptResource"/>
      <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
    </handlers>
  </system.webServer>
  <runtime>
    <assemblyBinding appliesTo="v2.0.50727" xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Extensions" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Extensions.Design" publicKeyToken="31bf3856ad364e35"/>
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

我的项目中似乎既有web.config也有Web.config。我不确定这是不是一个问题。

对于一个简单的基于windows的网页来说，这似乎是一个巨大的扩展，但我的老板希望我使用asp和c#。你知道它为什么缺少FileUpload1以及如何修复它吗？

asp.net

回答 1

Stack Overflow用户

回答已采纳

发布于 2019-03-15 04:04:57

如果要将控件添加到webform的ASPX页并从代码隐藏中使用/修改它，则需要在代码隐藏中使用与ASPX的给定ID相同的名称来声明它。

public partial class CS : System.Web.UI.Page
{
    protected GridView GridView1;
    protected PhotoUpload PhotoUpload1;
    // more page code
}

如果您使用设计器视图添加控件，这些定义通常会自动添加到生成的‘MyPage.designer er.cs’中。

无论哪种方式，一旦您将定义添加到后端，您应该能够在前端ASPX中定义PhotoUpload控件，如下所示：

<asp:FileUpload ID="FileUpload1" runat="server" />

我建议你尽早养成使用比GridView1和FileUpload1更有意义的名称的习惯，一旦你的页面上有多个相同类型的控件，当你同时为Label6和Label4设置值时，试图记住Label1是用来做什么的就会让人感到困惑。

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页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/55171037

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