winform，用c#链接 sql server。对数据库进行查询记录，增加记录，删除记录。，修改记录。

Question

对数据库进行查询记录，增加记录，删除记录。，修改记录。

Answer 1

首先C#连接Sql的方式有很多，我说一下我经常使用比较好理解的方法：
C#连接Sql的步骤：
①：添加引用using System.Data.SqlClient;
②：创建连接字符串;
③：创建SQL执行语句;
③：创建SqlConnection对象;
④：打开连接;
⑤：创建SqlCommand对象;
⑥：关闭连接;
-----------------------------------下面是增加记录的代码----------------------------------
string ConnString = "Data Source=SAWYER-PC;Initial Catalog=InfoDemo;Persist Security Info=True;User ID=sa;Password=123"; //创建连接字符串;

string SQL = "insert into Employee values('" + textBox1.Text + "','" + textBox2.Text + "','" + comboBox_Sex.SelectedItem.ToString() + "','" + dateTimePicker1.Value.Date.ToString() + "','" + dateTimePicker2.Value.Date.ToString() + "','" + comboBox_EdB.SelectedItem.ToString() + "','" + comboBox1.SelectedValue.ToString() + "','" + comboBox7.SelectedValue.ToString() + "','" + comboBox4.SelectedValue.ToString() + "')";//创建SQL执行语句，根据你程序的实际情况；

SqlConnection Conn = new SqlConnection(ConnString);//创建SqlConnection对象;

Conn.Open();//打开连接;

SqlCommand cmd = new SqlCommand(SQL, Conn);创建SqlCommand对象;
cmd.ExecuteNonQuery();
Conn.Close();//关闭连接

----------------------查询，并将查询的结果绑定到 dataGridView1经行显示-------------------------
string ConnString = "Data Source=SAWYER-PC;Initial Catalog=InfoDemo;Persist Security Info=True;User ID=sa;Password=123";
SqlConnection Connection;
SqlDataAdapter Adapter;
string SQL = "select * from Employee";
Connection = new SqlConnection(ConnString);
Connection.Open();
Adapter = new SqlDataAdapter(SQL, Connection);
DataSet data = new DataSet();
Adapter.Fill(data);
if (data.Tables.Count > 0)
{
dataGridView1.DataSource = data.Tables[0];
}
Connection.Close();

Answer 2

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using Common;

namespace DataAccessLayer
{
public class stuDataAccessLayer
{
/**
* item 表示传过来的实体集的对象，它包含数据表的四个属性;
* item.ID, item.Name, item.Age, item.Sex 分别表示数据表StudentBasicInformation的
* 四个属性: ID,age,name,sex
* ConnStr 表示 连接数据库的连接语句;
* getSqlConnection(string str)打开一个数据库连接命令;
* sqlstr 表示对数据库的各种操作(插入、查询、删除、显示)的操作语句 ;
* NewTCF(string sqlstr) 返回一个带有需要显示的项的 table表的共同方法;
* sqlDA 打开一个操作数据表的适配器;
* table.Locale 指定表的区域化显示;
* sqlDA.Fill(table) 关联一个数据表和一个sql查询结果表 ;
**/
private readonly string ConnStr = "Data Source=localhost;database=StudentDemo;uid=sa;pwd=123456";
SqlConnection Conn = null;
private SqlConnection getSqlConnection(string str)
{
if (Conn == null || Conn.State == ConnectionState.Closed)
{
Conn = new SqlConnection(str);
}
return Conn;
}
private DataTable NewTCF(string sqlstr)
{
SqlDataAdapter sqlDA = new SqlDataAdapter(sqlstr,getSqlConnection(ConnStr));
DataTable table = new DataTable();
try
{
Conn.Open();
table.Locale = System.Globalization.CultureInfo.InvariantCulture;
sqlDA.Fill(table); //使得适配器 与 操作的表相关联
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
return null;
}
finally
{
sqlDA.Dispose();
Conn.Close();
}
return table;
}
/// <summary>
/// 底层操作数据库，把传过来的实体类对象item的各个属性值添加到数据库中,并显示操作后的结果;
/// </summary>
public DataTable Insert(stuCommon item)
{
string strInsert = string.Format("Insert into StudentBasicInformation values ('{0}','{1}','{2}','{3}')",
item.ID, item.Name, item.Age, item.Sex);
return NewTCF(strInsert);
}

/// <summary>
/// 底层操作数据库，用参数item.ID值查询数据库的记录,若找到就显示;
/// </summary>
/// <param name="item"></param>
/// <returns></returns>
public DataTable Select(stuCommon item)
{
string strSelect = string.Format("select * from StudentBasicInformation where ID={0}",item.ID);
return NewTCF(strSelect);
}

/// <summary>
/// 底层操作数据库,用参数item.ID来删除数据库的一条记录，并显示操作后的结果;
/// </summary>
/// <param name="item"></param>
public DataTable Delete(stuCommon item)
{
string strDelete = string.Format("Delete from StudentBasicInformation where ID = '{0}'",item.ID);
return NewTCF(strDelete);
}

/// <summary>
/// 显示数据库的全部记录;
/// </summary>
public DataTable ShowAllValues()
{
string strShow = "select 学号=ID,姓名=name,年龄=age,性别=sex from StudentBasicInformation";
return NewTCF(strShow);
}

}
}

Answer 3

这是我以前自己写的一个类，用于操作数据库的，一般的曾删减操作，以及复杂点的操作都可以通过这个类的实现。

/// <summary>
///DB 的摘要说明
/// </summary>
public class DB
{
private static string strConn = "";
public DB()
{
strConn = System.Configuration.ConfigurationManager.AppSettings["strConn"];

}

public SqlConnection createSqlConn()
{
SqlConnection Conn = null;
try
{
Conn = new SqlConnection(strConn);
}
catch (SqlException ex)
{
MessageBox.Show("创建数据库连接出错，请检查您的连接串:" + ex.Message);
Conn = null;
}
return Conn;
}

public SqlDataReader ExecQuery(string sql)
{
SqlDataReader sdr = null;
SqlCommand cmd = null;
SqlConnection Conn = createSqlConn();
if (Conn.State != ConnectionState.Open)
{
Conn.Open();
}
try
{
cmd = new SqlCommand(sql, Conn);
sdr = cmd.ExecuteReader();

}
catch (SqlException ex)
{
MessageBox.Show("数据库查询出错，请检查您的Sql查询语句:" + ex.Message);
sdr = null;
}

return sdr;

}

public DataSet ExecQuery(string sql,string tableName)
{
DataSet ds = new DataSet();
SqlDataAdapter da = null;
SqlCommand cmd= null;
SqlConnection Conn = createSqlConn();
if (Conn.State != ConnectionState.Open)
{
Conn.Open();
}
try
{

cmd = new SqlCommand(sql, Conn);
da = new SqlDataAdapter(cmd);
da.Fill(ds, tableName);

}
catch (SqlException ex)
{
MessageBox.Show("数据库查询出错，请检查您的Sql查询语句:" + ex.Message);
ds = null;
}

return ds;

}

public int ExecUpdate(string sql)//这包括插入、删除、和更新操作
{
SqlCommand cmd = null;
int effectRow = 0;
SqlConnection Conn = createSqlConn();
if (Conn.State != ConnectionState.Open)
{
Conn.Open();
}
try
{
cmd = new SqlCommand(sql, Conn);
effectRow = cmd.ExecuteNonQuery();
}
catch (SqlException ex)
{
MessageBox.Show("数据库更新出错，请检查您的Sql更新语句:" + ex.Message);
effectRow = 0;
}
if (Conn.State == ConnectionState.Open)
{
Conn.Close();
}
return effectRow;

}

}

Answer 4

sqlconnection scn=new sqlconnection(连接字符串)
sqlcommand scm=new sqlcommand（sql语句,scn）

Answer 5

恩恩 下面不错么