using System;

 using System.Collections.Generic;

 using System.ComponentModel;

 using System.Configuration;

 using System.Data;

 using System.Data.SqlClient;

 using System.Drawing;

 using System.Linq;

 using System.Text;

 using System.Threading.Tasks;

 using System.Windows.Forms;

 namespace _01SQLAndAdo.Net

 {

     public partial class SqlData2DataGirdView : Form

     {

         public SqlData2DataGirdView()

         {

             InitializeComponent();

         }

         private void SqlData2DataGirdView_Load(object sender, EventArgs e)

         {

             string connStr = ConfigurationManager.ConnectionStrings["sql"].ConnectionString;

             string commandText = @"SELECT TOP 1000 [User_ID]

                                     ,[User_Name]

                                     ,[User_Gender]

                                     ,[User_Age]

                                     ,[User_Address]

                                     ,[User_Birthday]

                                     ,[User_Remark]

                                     ,[User_Money]

                                     ,[User_GUIDDemo]

                                     ,[User_Pwd]

                                      FROM[LJK_SQLServerDB].[dbo].[User_Info]";

             using (SqlConnection conn = new SqlConnection(connStr))

             {

                 using (SqlDataAdapter adapter = new SqlDataAdapter(commandText, connStr))

                 {

                     //DataSet方式，查询多张表的时候应用

                     //DataSet dataSet=new DataSet();

                     //adapter.Fill(dataSet,"demo");

                     //this.dgvUserInfo.DataSource = dataSet.Tables["demo"];

                     DataTable dataTable = new DataTable();

                     //填充之前不需要打开数据库连接，Adaper会自动打开连接，并执行SQL

                     //Fill方法内部：

                     //1. 先判断SqlConnection是否初始化，如果没有打开链接，那么打开连接。

                     //2. 初始化一个Select(commandText) SqlCommand对象

                     //3. 通过cmd对象执行，然后返回一个SqlReader对象。

                     //4. 读取数据库中的数据，然后填充到DataTable上去

                     adapter.Fill(dataTable); //把数据库中的数据 填充到 内存表中

                     //把内存表显示到DataGirdView上去

                     // this.dgvUserInfo.DataSource = dataTable;

                     // var o = dataTable.Rows[0][1];

                     // dataRow["列名"];       //弱类型

                     //user.UserInfo           //强类型，出错概率下降

                     List<UserInfo> userInfoList = new List<UserInfo>();

                     foreach (DataRow dataRow in dataTable.Rows)

                     {

                         Console.WriteLine(dataRow["User_Id"] + "         " + dataRow[]);

                         Console.WriteLine(dataRow["User_Name"] + "         " + dataRow[]);

                         Console.WriteLine(dataRow["User_Age"] + "         " + dataRow[]);

                         Console.WriteLine(dataRow["User_Pwd"] + "         " + dataRow[]);

                         UserInfo userInfo = new UserInfo();

                         userInfo.UserId = int.Parse(dataRow["User_ID"].ToString());

                         userInfo.UserName = dataRow["User_Name"].ToString();

                         if (!string.IsNullOrEmpty(dataRow["User_Age"].ToString()))

                         {

                             userInfo.UserAge = int.Parse(dataRow["User_Age"].ToString());

                             // userInfo.UserAge = dataRow["User_Age"].ToString();

                             // userInfo.UserAge = 1;

                         }

                         else

                         {

                             userInfo.UserAge = ;

                         }

                         if (!string.IsNullOrEmpty(dataRow["User_Pwd"].ToString()))

                         {

                             userInfo.UserPwd = int.Parse(dataRow["User_Pwd"].ToString());

                         }

                         else

                         {

                             userInfo.UserPwd = ;

                         }

                         userInfoList.Add(userInfo);

                         //把DataTabel的数据转成List<UserInfo>

                     }

                     this.dgvUserInfo.DataSource = userInfoList;

                 }

             }

         }

     }

 }