3_05_MSSQL课程_Ado.Net_SQLDataAdapter

  1 using System;
  2 using System.Collections.Generic;
  3 using System.ComponentModel;
  4 using System.Configuration;
  5 using System.Data;
  6 using System.Data.SqlClient;
  7 using System.Drawing;
  8 using System.Linq;
  9 using System.Text;
 10 using System.Threading.Tasks;
 11 using System.Windows.Forms;
 12 
 13 namespace _01SQLAndAdo.Net
 14 {
 15     public partial class SqlData2DataGirdView : Form
 16     {
 17         public SqlData2DataGirdView()
 18         {
 19             InitializeComponent();
 20         }
 21 
 22         private void SqlData2DataGirdView_Load(object sender, EventArgs e)
 23         {
 24 
 25             string connStr = ConfigurationManager.ConnectionStrings["sql"].ConnectionString;
 26             string commandText = @"SELECT TOP 1000 [User_ID]
 27                                     ,[User_Name]
 28                                     ,[User_Gender]
 29                                     ,[User_Age]
 30                                     ,[User_Address]
 31                                     ,[User_Birthday]
 32                                     ,[User_Remark]
 33                                     ,[User_Money]
 34                                     ,[User_GUIDDemo]
 35                                     ,[User_Pwd]
 36                                      FROM[LJK_SQLServerDB].[dbo].[User_Info]";
 37             using (SqlConnection conn = new SqlConnection(connStr))
 38             {
 39                 using (SqlDataAdapter adapter = new SqlDataAdapter(commandText, connStr))
 40                 {
 41                     //DataSet方式，查询多张表的时候应用
 42                     //DataSet dataSet=new DataSet();
 43                     //adapter.Fill(dataSet,"demo");
 44                     //this.dgvUserInfo.DataSource = dataSet.Tables["demo"];
 45 
 46                     DataTable dataTable = new DataTable();
 47                     //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
 48                     //Fill方法内部：
 49                     //1. 先判断SqlConnection是否初始化，如果没有打开链接，那么打开连接。
 50                     //2. 初始化一个Select(commandText) SqlCommand对象
 51                     //3. 通过cmd对象执行，然后返回一个SqlReader对象。
 52                     //4. 读取数据库中的数据，然后填充到DataTable上去
 53                     adapter.Fill(dataTable); //把数据库中的数据 填充到 内存表中
 54                     //把内存表显示到DataGirdView上去
 55                     // this.dgvUserInfo.DataSource = dataTable;
 56 
 57                     // var o = dataTable.Rows[0][1];
 58 
 59                     // dataRow["列名"];       //弱类型
 60                     //user.UserInfo           //强类型，出错概率下降
 61                     List<UserInfo> userInfoList = new List<UserInfo>();
 62                     foreach (DataRow dataRow in dataTable.Rows)
 63                     {
 64                         Console.WriteLine(dataRow["User_Id"] + "         " + dataRow[0]);
 65                         Console.WriteLine(dataRow["User_Name"] + "         " + dataRow[1]);
 66                         Console.WriteLine(dataRow["User_Age"] + "         " + dataRow[2]);
 67                         Console.WriteLine(dataRow["User_Pwd"] + "         " + dataRow[3]);
 68                         UserInfo userInfo = new UserInfo();
 69                         userInfo.UserId = int.Parse(dataRow["User_ID"].ToString());
 70                         userInfo.UserName = dataRow["User_Name"].ToString();
 71                         if (!string.IsNullOrEmpty(dataRow["User_Age"].ToString()))
 72                         {
 73                             userInfo.UserAge = int.Parse(dataRow["User_Age"].ToString());
 74                             // userInfo.UserAge = dataRow["User_Age"].ToString();
 75                             // userInfo.UserAge = 1;
 76                         }
 77                         else
 78                         {
 79                             userInfo.UserAge = 0;
 80                         }
 81 
 82                         if (!string.IsNullOrEmpty(dataRow["User_Pwd"].ToString()))
 83                         {
 84                             userInfo.UserPwd = int.Parse(dataRow["User_Pwd"].ToString());
 85                         }
 86                         else
 87                         {
 88                             userInfo.UserPwd = 11;
 89                         }
 90 
 91                         userInfoList.Add(userInfo);
 92 
 93 
 94                         //把DataTabel的数据转成List<UserInfo>
 95 
 96                     }
 97 
 98                     this.dgvUserInfo.DataSource = userInfoList;
 99 
100                 }
101 
102             }
103 
104 
105         }
106     }
107 }