Textbox读取数据，插入，查询数据3.0版本

1.0版本在此：https://www.yuque.com/shuiyun-evwnf/nm9z7v/bng07b
介绍：将数据库中的某一个内容显示到TextBox中，并且可以通过他来插入新数据。
1、数据库准备工作（数据库名称为student）

2、Form准备工作（数据库提前连接好）

3、首先在程序中引入命名空间
using System.Data.SqlClient;
4、插入功能

        private void btnInsert_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "data source=.;initial catalog=student;integrated security=true";
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "insert into tbl_student values('"+txtID.Text+"','"+txtname.Text+"')";//两个txtbox分别命名为txtID、txtname
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();
            MessageBox.Show("插入成功！");
        }

5、读取功能，将指定的内容（select 。。。where。。。限定条件）显示到TextBox中。
如果需要显示的内容是string类型，则用下边这个

        private void btnRead_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "data source=.;initial catalog=student;integrated security=true";
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandType=CommandType.Text;
            cmd.CommandText = "select name from tbl_student where ID='2'";
            conn.Open();
            string d = Convert.ToString(cmd.ExecuteScalar());//////////这里会更改
            conn.Close();
            txtname.Text = d.ToString();
        }

如果需要显示的内容是int类型，则用下边这个

        private void btnRead_Click(object sender, EventArgs e)
        {/*
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "data source=.;initial catalog=student;integrated security=true";
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandType=CommandType.Text;
            cmd.CommandText = "select name from tbl_student where ID='2'";
            conn.Open();
            string d = Convert.ToString(cmd.ExecuteScalar());
            conn.Close();
            txtname.Text = d.ToString();
        */
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "data source=.;initial catalog=student;integrated security=true";
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "select ID from tbl_student where name='范云川'";
            conn.Open();
            int d = Convert.ToInt32(cmd.ExecuteScalar());//////////这里更改了
            conn.Close();
            txtID.Text = d.ToString();
        }

6、显示内容，将某一列内容显示到listbox中

        private void btnshow_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "data source=.;initial catalog=student;integrated security=true";
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = "select ID from tbl_student where name='范云川'";
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            while (dr.Read())
                lstName.Items.Add(dr.GetInt32(0));  //如果需要显示的内容是string，则需更改GetInt32，0代表第0列
                dr.Close();
            conn.Close();
        }

7、DataGridView查询（2020/11/6 12：24 添加）

      private void btnUserFind_Click(object sender, EventArgs e) //点击查询按钮
        {
            ArrayList dbRecordsHolder = new ArrayList();
            SqlConnection conn = new SqlConnection("data source=.;initial catalog=PLA;integrated security=true;");//需要修改数据库名称
            SqlCommand cmd = new SqlCommand("Select * from tbl_UserInfo where 身份证号='" + txtUserIDFind.Text + "' or 姓名='" + txtUserNameFind.Text + "' ", conn);//需要修改表名
            conn.Open();
            SqlDataReader dr;
            dr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
            if (dr.HasRows)
            {
                foreach (DbDataRecord rec in dr)
                {
                    dbRecordsHolder.Add(rec);
                }
            }
            dr.Close();
            dataGridView1.DataSource = dbRecordsHolder;
        }

8、参考教材资料和C#工程将存放在百度云盘里。
链接：https://pan.baidu.com/s/1AthQjC733I0ZuXAyHIEIjQ
提取码：540v
9、一点点拙见，如有错误，请指出，谢谢(^▽^)