C#_数据库基本交互

//app.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" />
    </startup>
  <connectionStrings>
    <add name="dbConnStr" connectionString="Data Source=服务器地址;Initial Catalog=数据库;User ID=账号（可以是sa）;Password=密码"/>
  </connectionStrings>
</configuration>

//content

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace DataBaseTest
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            using (SqlConnection conn = new SqlConnection("Data Source=xxx;Initial Catalog=xxx;User ID=sa;Password=xxx"))
            {
                conn.Open();
                using(SqlCommand cmm = conn.CreateCommand())
                {
                    //cmm.CommandText = "select * from T_Student";
                   //没有返回值
                   //cmm.ExecuteNonQuery();
                   //有一个返回值
                   //insert into T_Student(Name,Age) output inserted.Id values （'aaa',123）;
                   // object o = cmm.ExecuteScalar();
                   //多个返回值
                    //using (SqlDataReader reader = cmm.ExecuteReader())
                    //{
                    //    while(reader.Read())
                    //    {
                    //        MessageBox.Show(reader.GetString(1));
                    //    }
                    //}
                    cmm.CommandText = "select * from T_Student where Name=@Name";
                    cmm.Parameters.Add(new SqlParameter("@Name", txtSearch.Text));
                    //查询输入内容
                    using (SqlDataReader reader = cmm.ExecuteReader())
                    {
                        while (reader.Read())
                        {
                            MessageBox.Show(reader.GetString(1));
                        }
                    }

                }
            }
            MessageBox.Show("successful");
        }

        private void 离线数据集_Click(object sender, RoutedEventArgs e)
        {
            using (SqlConnection conn = new SqlConnection("Data Source=xxx;Initial Catalog=xxxx;User ID=sa;Password=xxx"))
            {
                conn.Open();
                using (SqlCommand cmm = conn.CreateCommand())
                {
                    cmm.CommandText = "select * from T_Student where Name=@Name";
                    cmm.Parameters.Add(new SqlParameter("@Name", txtSearch.Text));

                    //SqlDataAdapter是一个把查询结果填充到DataSet中
                    SqlDataAdapter adapt = new SqlDataAdapter(cmm);
                    //本地集合
                    DataSet dataset = new DataSet();
                    adapt.Fill(dataset);

                    DataTable table = dataset.Tables[0];

                    DataRowCollection rows = table.Rows;

                    for (int i = 0; i < rows.Count; i++)
                    {
                        DataRow row = rows[i];
                        int age = (int)row["Age"];
                        string name = (string)row["Name"];
                        MessageBox.Show("name: "+name+" age: "+age);

                    }
                }
            }
        }

        private void btnConStr_Click(object sender, RoutedEventArgs e)
        {
            //需要添加system.Configration reference
            string connStr = ConfigurationManager.ConnectionStrings["dbConnStr"].ConnectionString;
            MessageBox.Show(connStr);
            //SqlHelper.ExecuteNonQuery("insert into T_Student(Name,Age) values ('eee',123)");
            MessageBox.Show("succeed insert");

            //DataSet dataset = new DataSet();
            //using (SqlConnection conn = new SqlConnection(connStr))
            //{
            //    conn.Open();
            //    using (SqlCommand cmm = conn.CreateCommand())
            //    {
            //        cmm.CommandText = "select * from T_Student where Name=@Name";
            //        cmm.Parameters.Add(new SqlParameter("@Name", txtSearch.Text));

            //        //SqlDataAdapter是一个把查询结果填充到DataSet中
            //        SqlDataAdapter adapt = new SqlDataAdapter(cmm);
            //        //本地集合

            //        adapt.Fill(dataset);

            //        DataTable table = dataset.Tables[0];

            //        DataRowCollection rows = table.Rows;

            //        for (int i = 0; i < rows.Count; i++)
            //        {
            //            DataRow row = rows[i];
            //            int age = (int)row["Age"];
            //            string name = (string)row["Name"];
            //            MessageBox.Show("name: " + name + " age: " + age);

            //        }
            //    }
            //}

        }

        private void Button_Click_2(object sender, RoutedEventArgs e)
        {
            //DataSet ds = SqlHelper.ExecuteDataSet("select * from T_Student");
            //foreach (DataRow row in ds.Tables[0].Rows)
            //{
            //    string name = (string)row["Name"];
            //    MessageBox.Show(name);
            //}
            DataTable ds = SqlHelper.ExecuteDataTable("select * from T_Student");
            foreach (DataRow row in ds.Rows)
            {
                string name = (string)row["Name"];
                MessageBox.Show(name);
            }
        }
    }
}