ConnectionString 属性尚未初始化。
我在web.config中配置了链接字符串 
  <connectionStrings>  
     <add   name= "OTsoftConnectionString "   connectionString= "Data      Source=172.15.0.30;Initial   Catalog=OTsoft;User   ID=sa;Password=otsoft "   providerName= "System.Data.SqlClient "   />  
  </connectionStrings>  
 然后我定义了一个类 
 public   class   DataConnection 
 { 
 public   string   sysconnstring   =   ConfigurationSettings.AppSettings[ "tetweb_zjsysConnectionString "]; 
 public   SqlConnection   stoCon; 
 public   DataConnection() 
 {   
 sysCon=new      SqlConnection   (sysconnstring); 
 } 
 } 
 在另一个类中定义 
 public   System.Data   .DataTable   GetTable(SqlConnection   myCon,string   SqlState) 
 		{ 
 			System.Data   .DataTable   myTable=new   System.Data   .DataTable(); 
 			try 
 			{ 
 				myCon.Open   (); 
 				SqlDataAdapter   myAdapter=new   SqlDataAdapter   (SqlState,myCon); 
 				myAdapter.Fill(myTable); 
 				myAdapter.Dispose   (); 
 			} 
 			catch(Exception   MyInf) 
 			{ 
 				throw   MyInf; 
 			} 
 			finally 
 			{ 
 				myCon.Close   (); 
 			} 
 			return   myTable;   
 		} 
 我在.cs中调用这两个类,结果类老是出现“ConnectionString   属性尚未初始化。”的错误 
------解决方案--------------------public string sysconnstring = ConfigurationSettings.AppSettings[ "tetweb_zjsysConnectionString "]; 
 public SqlConnection stoCon; 
 public DataConnection() 
 {   
 sysCon=new  SqlConnection (sysconnstring); 
 }   
 ----->    
 public SqlConnection stoCon; 
 public DataConnection() 
 {   
 sysCon=new  SqlConnection (ConfigurationSettings.AppSettings[ "tetweb_zjsysConnectionString "]); 
 }
------解决方案-------------------- <connectionStrings>  
   <add key= "connectionString " value= "Data  Source=172.15.0.30;Initial Catalog=OTsoft;User ID=sa;Password=otsoft "/>  
  </connectionStrings>  
 然后我定义了一个类 
 public class DataConnection 
 { 
 public string sysconnstring = ConfigurationSettings.AppSettings[ "connectionString "]; 
 public SqlConnection stoCon; 
 public DataConnection() 
 {   
 sysCon=new  SqlConnection (sysconnstring); 
 } 
 } 
 . 
 .......