求助 哪错误

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;namespace mdf
{
    class Program
    {
        static void Main(string[] args)
        {
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString =@"Data source=.\;Initial Catalog=lianxi;User ID=sa;Password=fengjianhua";
            conn.Open();
            SqlCommand cmd = new SqlCommand();
            cmd.CommandText = "insert into fjh(name) values ('abf')";
            cmd.ExecuteNonQuery();----------------提示：ExecuteNonQuery: Connection 属性尚未初始化。
            Console.WriteLine("插入成功");
            Console.WriteLine("连接成功");
            Console.ReadKey();
        }
    }
}

Answer 1

 conn.ConnectionString =@"Data source=.\;Initial Catalog=lianxi;User ID=sa;Password=fengjianhua";
==========
 conn.ConnectionString =@"Data source=.;Initial Catalog=lianxi;User ID=sa;Password=fengjianhua";

Answer 2

如果数据库是EXPRESS版本的话：
Data source=./sqlexpress

Answer 3

sorry SqlCommand cmd = new SqlCommand(conn );

Answer 4

SqlConnection conn = new SqlConnection();
  conn.ConnectionString =@"Data source=.\;Initial Catalog=lianxi;User ID=sa;Password=fengjianhua";
=>SqlConnection conn = new SqlConnection("server=.;database=lianxi;uid=sa;pwd=fengjianhua");

Answer 5

sorry SqlCommand cmd = new SqlCommand(conn );

Answer 6

改成这样：conn.ConnectionString =@"Data source=(local);Initial Catalog=lianxi;User ID=sa;Password=fengjianhua";

Answer 7

 SqlConnection conn = new SqlConnection();
  conn.ConnectionString =@"Data source=.;Initial Catalog=lianxi;User ID=sa;Password=fengjianhua";
  conn.Open();
  SqlCommand cmd = new SqlCommand("insert into fjh(name) values ('abf')",conn);    cmd.ExecuteNonQuery();  
  Console.WriteLine("插入成功");
  Console.WriteLine("连接成功");
  Console.ReadKey();