小编kri*_*ech的帖子

提前致歉；我正在尝试学习C＃的第3天。

我被指示建立字典的哈希表；没问题。我看到那已经建立。我现在需要遍历哈希集，如果字典的键！=特定字符串，则将条目复制到新列表中。有人可以解释一下完成此看似简单任务的正确语法吗？

var goodSongs = new List<Dictionary<string,string>>();

var allSongs = new HashSet<Dictionary<string, string>>();

Dictionary<string, string> meatloaf = new Dictionary<string, string>();
meatloaf.Add("Meatloaf", "Paradise By The Dashboard Light");

Dictionary<string, string> aerosmith = new Dictionary<string,string>();
aerosmith.Add("Aerosmith", "Cryin'");

Dictionary<string, string> nickelback = new Dictionary<string, string>();
nickelback.Add("Nickelback", "Rockstar");

allSongs.Add(nickelback);
allSongs.Add(aerosmith);
allSongs.Add(meatloaf);

//foreach loop to iterate dictionaries goes here

目标-要摆脱困境，希望学习C＃，并决定我是否要继续努力下去。谢谢大家。

我不明白为什么我会收到这个错误。我正在尝试从映射的配置文件的 appSettings 部分获取值。

这是我的配置文件：

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <configSections>
    <section name="cachingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Caching.Configuration.CacheManagerSettings, Microsoft.Practices.EnterpriseLibrary.Caching, Version=4.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" />
  </configSections>
  <appSettings>    
    <!-- Need to configure.-->
    <add key="ServiceDisplayName" value="Scheduler-aaaa" />
    <add key="ServiceName" value="SchedulerService-aaaa" />
    <add key="SchedulerTime" value="05:00 AM" />
    <!-- 12 hour format-->
    <add key="RoutingInterval" value="5"/>
    <add key="ADSyncInterval" value="2"/>
    <add key="ReportPath" value="C:\inetpub\wwwroot\aaaa\Reports\DefaultReports"/>
    <add key="ReportPathCustom" value="C:\inetpub\wwwroot\aaaa\Reports\CustomReports"/>
    <add key="ApplicationUrl" value="https://mms.com/aaaa/"/>
    <add key="ServiceUrl" value="https://temp.com/aaaa/Inspection/Service"/>
    <add key="ClientSettingsProvider.ServiceUri" value="" />
    <add key="EmailAddress" value="support@mms.com" />
  </appSettings>
  <connectionStrings>
    <add name="CustomerDB" connectionString="Provider=SQLOLEDB.1;Data Source=.\temp;User ID=mm;PWD=mm;Initial Catalog=35testupdate" />
  </connectionStrings>
  <cachingConfiguration />
  <startup> …