ASP.NET(C#)连接数据库和操作数据库

首先加入命名空间using System.Data.SqlClient;
1.查询
SqlConnection conn = new SqlConnection();
conn = new SqlConnection();
conn.ConnectionString = "Data Source=(local);Initial Catalog=数据库名;UserID=sa;Password=123456";
conn.Open();
string strsql=“select语句";
SqlCommand cmd = new SqlCommand(strsql, conn);
SqlDataReader sqlreader = cmd.ExecuteReader();
while (sqlreader.Read())
{
txtName.Text= sqlreader["列名"].ToString();
}
sqlreader.Close();
conn.Close();
2.插入、更新、删除
SqlConnection conn = new SqlConnection();
conn = new SqlConnection();
conn.ConnectionString = "Data Source=(local);Initial Catalog=数据库名;UserID=sa;Password=123456";
conn.Open();
strsql="update语句";// strsql="插入语句";//strsql="删除语句";
SqlCommand sqlcmd2 = new SqlCommand(strsql, conn);
int iResult = sqlcmd2.ExecuteNonQuery();
conn.Close();