C# 检查网络是否连通

        [DllImport( " wininet.dll " )]
         private   extern   static   bool  InternetGetConnectedState( out   int  connectionDescription,  int  reservedValue);
         private   bool  IsConnected()
        {

             int  I  =   0 ;

             bool  state  =  InternetGetConnectedState( out  I,  0 );

             return  state;

        }

调用方法：

 

bool  state  =  IsConnected();    // True 为连通   False 为断开