访问web.config中数据库连接字符串

ConfigurationManager 成员
提供对客户端应用程序配置文件的访问。无法继承此类。

private  DataSet RunQuery(SqlCommand sqlQuery)
    {
         string  connectionString  =
            ConfigurationManager.ConnectionStrings
            [ " NorthwindConnectionString " ].ConnectionString;
        SqlConnection DBConnection  =
             new  SqlConnection(connectionString);
        SqlDataAdapter dbAdapter  =   new  SqlDataAdapter();
        dbAdapter.SelectCommand  =  sqlQuery;
        sqlQuery.Connection  =  DBConnection;
        DataSet resultsDataSet  =   new  DataSet();
         try
        {
            dbAdapter.Fill(resultsDataSet);
        }
         catch
        {
            labelStatus.Text  =   " Unable to connect to SQL Server. " ;
        }
         return  resultsDataSet;
    }

//  Get connectionStrings.
static   void  GetConnectionStrings()
{
     //  Get the connectionStrings.
    ConnectionStringSettingsCollection connectionStrings  =
         ConfigurationManager.ConnectionStrings;

     //  Get the collection enumerator.
    IEnumerator connectionStringsEnum  =
        connectionStrings.GetEnumerator();

     //  Loop through the collection and 
     //  display the connectionStrings key, value pairs.
     int  i  =   0 ;
    Console.WriteLine( " Connection strings. " );
     while  (connectionStringsEnum.MoveNext())
    {
         string  name  =  connectionStrings[i].Name;
        Console.WriteLine( " Name: {0} Value: {1} " ,
        name, connectionStrings[name]);
        i  +=   1 ;
    }

}