如果我创建一个新项目并将其安装在该项目上，它工作正常，但是对我正在处理的项目执行此操作会出现此错误：
我已尝试替换所有 dll 文件、packages.xml、web.config。使用我安装 web 帮助程序之前的文件，但问题仍然存在。
现在显示错误的这行代码（第 50 行）完全相同，并且在安装之前运行良好。
Server Error in '/' Application.
Configuration Error
Description: An error occurred during the processing of a configuration file required to service this request. Please review the specific error details below and modify your configuration file appropriately.
Parser Error Message: The connection name 'DefaultConnection' was not found in the applications configuration or the connection string is empty.
Source Error:
Line 48: <membership defaultProvider="DefaultMembershipProvider">
Line 49: <providers>
Line 50: <add name="DefaultMembershipProvider" type="System.Web.Providers.DefaultMembershipProvider, System.Web.Providers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" connectionStringName="DefaultConnection" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" />
Line 51: </providers>
Line 52: </membership>
Source File: C:\Users\BJARKE\Desktop\OlabsRepositories\iconbench\IconBench\web.config Line: 50
Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17626
有什么建议么？