C#连接SQL Server

首先，确保引用如下两个类库

using System.Data;
using System.Data.SqlClient;

连接本机SQL服务器

string strConnection = "Trusted_Connection=SSPI;";
strConnection += "Database=数据库名称;Server=(local)\\SQLEXPRESS;";
//如果数据库设置了实例名，则需要填写相应实例名
strConnection += "Connect Timeout=30";
SqlConnection objConnection = new SqlConnection(strConnection);
objConnection.Open();

连接远程SQL服务器

string strConnection ="user id=sa;password=11";
strConnection+="initial catalog=数据库名称;Server=数据库服务器地址;";
strConnection+="Connect Timeout=30";
SqlConnection objConnection = new SqlConnection(strConnection);
objConnection.open();

之后就是执行Command返回SQL查询结果了