c#自主学习 3增删改查的可视化实现

	using System;
using System.Collections.Generic;
using System.ComponentModel;
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 TestCURD
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // TODO: 这行代码将数据加载到表“studentDataSet.Student”中。您可以根据需要移动或删除它。
            this.studentTableAdapter.Fill(this.studentDataSet.Student);

        }

        private void textBox3_TextChanged(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)  //增加
        {
            String StuID = textBox1.Text.Trim();
            String StuName = textBox2.Text.Trim();
            String StuSex = textBox3.Text.Trim();
            String StuSdept = textBox5.Text.Trim();
            String StuAge = textBox4.Text.Trim();

            //数据库的连接定义
            SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=Student;User ID=sa;Password=123456");
            
            try
            {
                con.Open();//数据库打开
                string insertStr = "INSERT INTO Student (Sno,Sname,Ssex,Sage,Sdept)    " +
                    "VALUES ('" + StuID + "','" + StuName + "','" + StuSex + "','" + StuAge + "'," + StuSdept + ")";
                SqlCommand cmd = new SqlCommand(insertStr, con);
                cmd.ExecuteNonQuery();//执行语句
            }
            catch//try中有错误执行
            {
                MessageBox.Show("输入数据违反要求!");
            }
            finally//数据库释放
            {
                con.Dispose();
            }
            this.studentTableAdapter.Fill(this.studentDataSet.Student);//刷新一遍
        }

        private void buttonDelete_Click(object sender, EventArgs e)//删除
        {
            //数据库连接,其实不需要每个都定义一遍,可以在外侧定义一遍
            SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=Student;User ID=sa;Password=123456");

            try
            {
                con.Open();
                string select_id = dataGridView1.SelectedRows[0].Cells[0].Value.ToString();//选择的当前行第一列的值,也就是ID
                string delete_by_id = "delete from Student where Sno=" + select_id;//sql删除语句
                SqlCommand cmd = new SqlCommand(delete_by_id, con);
                cmd.ExecuteNonQuery();
            }
            catch
            {
                MessageBox.Show("请正确选择行!");
            }
            finally
            {
                con.Dispose();
            }
            this.studentTableAdapter.Fill(this.studentDataSet.Student);

        }

        private void buttonRevise_Click(object sender, EventArgs e)//修改
        {
            String StuID = textBox1.Text.Trim();
            String StuName = textBox2.Text.Trim();
            String StuSex = textBox3.Text.Trim();
            String StuSdept = textBox5.Text.Trim();
            String StuAge = textBox4.Text.Trim();

            SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=Student;User ID=sa;Password=123456");
            try
            {
                con.Open();
                //根据学号进行修改
                string insertStr = "UPDATE Student SET Sname = '" + StuName + "'  WHERE Sno = '" + StuID + "'";
                SqlCommand cmd = new SqlCommand(insertStr, con);
                cmd.ExecuteNonQuery();

                string insertStr2 = "UPDATE Student SET SSex = '" + StuSex + "'  WHERE Sno = '" + StuID + "'";
                SqlCommand cmd2 = new SqlCommand(insertStr2, con);
                cmd2.ExecuteNonQuery();

                string insertStr3 = "UPDATE Student SET Sdept = '" + StuSdept + "'  WHERE Sno = '" + StuID + "'";
                SqlCommand cmd3 = new SqlCommand(insertStr3, con);
                cmd3.ExecuteNonQuery();

                string insertStr4 = "UPDATE Student SET Sage = '" + StuAge + "'  WHERE Sno = '" + StuID + "'";
                SqlCommand cmd4 = new SqlCommand(insertStr4, con);
                cmd4.ExecuteNonQuery();
            }
            catch
            {
                MessageBox.Show("输入数据违反要求!");
            }
            finally
            {
                con.Dispose();
            }
            this.studentTableAdapter.Fill(this.studentDataSet.Student);
        }

        private void buttonSelect_Click(object sender, EventArgs e)//查找
        {
            String StuID = textBox1.Text.Trim();
            String conn = "Data Source=.;Initial Catalog=Student;User ID=sa;Password=123456";
            SqlConnection sqlConnection = new SqlConnection(conn);  //实例化连接对象
            try
            {
                sqlConnection.Open();
                String select_by_id = "select * from Student where Sno='" + StuID + "'";
                SqlCommand sqlCommand = new SqlCommand(select_by_id, sqlConnection);
                SqlDataReader sqlDataReader = sqlCommand.ExecuteReader();
                BindingSource bindingSource = new BindingSource();
                bindingSource.DataSource = sqlDataReader;
                dataGridView1.DataSource = bindingSource;
            }
            catch
            {
                MessageBox.Show("查询语句有误,请认真检查SQL语句!");
            }
            finally
            {
                sqlConnection.Close();
            }
        }

        private void buttonClose_Click(object sender, EventArgs e)
        {
            Application.Exit();//关闭应用程序
        }
    }
}

操作代码块如上

c#自主学习 3增删改查的可视化实现_第1张图片
界面如上

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