Question

C# 判断数据库连接是否打开

Answer 1

根据平常的思维你应该在之前打开，然后判断它的状态。 测试代码如下： 1 连接数据库try{ String commandText="select count(*) from users"; SqlConnection conn = new SqlConnection(); conn.ConnectionString = "Data Source=(local);Initial Catalog=classmate;User Id=sa;Password=sa"; SqlCommand cmd = new SqlCommand(commandText,conn); conn.Open(); string count = cmd.ExecuteScalar().ToString(); if (conn.State == ConnectionState.Open){ Response.Write(count); Response.Write("数据库连接成功！"); Response.Write("<scriptalert('连接已打开')</script");} conn.Close(); if (conn.State == ConnectionState.Closed){ Response.Write("连接已关闭"); Response.Write("<scriptalert('连接已关闭')</script");}} Response.Write("数据库连接失败"+ex.Message);}}

Answer 2

参考代码及说明：
static void Main(string[] args)
{
//提供连接字符串
string connStr = @"server=.;database=Student;uid=sa;pwd=saa";
//using System.Data.SqlClient; //处理SQL Server对象
using (SqlConnection conn = new SqlConnection(connStr))
{
//open就是在连接数据库，如果连接成功，那么这句话会顺利结束，如果连接不成功，就会抛出一个异常
conn.Open();
Console.WriteLine("连接成功");
}
//输出连接成功
}