C#通过DataGridView对数据库进行增删改查

运行效果.png

一、准备数据库Student，数据表TableStudent

CREATE TABLE [dbo].[TableStudent] (
    [stuId]        INT           IDENTITY (1, 1) NOT NULL,
    [stuName]      NVARCHAR (32) NULL,
    [stuSex]       NCHAR (2)     NULL,
    [stuBirthdate] NVARCHAR (32) NULL,
    [stuPhone]     NVARCHAR (32) NULL,
    PRIMARY KEY CLUSTERED ([stuId] ASC)
);

二、获取数据库连接字符串

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Configuration;
using System.Data.SqlClient;
using System.Data;

namespace DataAdapterExample
{
    class sqlHelper
    {

        //获取数据库连接字符串
        public static string GetConnectionString()
        {
            return ConfigurationManager.ConnectionStrings["strConnect"].ConnectionString;
        }

        #region 封装一个执行SQL返回受影响的行数
        public static int ExecuteNoQuery(string sqlText,params SqlParameter[] parameters)
        {
            using (SqlConnection con = new SqlConnection(GetConnectionString()))
            {
                using (SqlCommand cmd = con.CreateCommand())
                {
                    con.Open();
                    cmd.CommandText = sqlText;
                    cmd.Parameters.AddRange(parameters.ToArray());
                    return cmd.ExecuteNonQuery();
                }
            }
        }
        #endregion

        #region 封装一个执行SQL返回查询结果中第一行第一列的值
        public static object ExecuteScalar(string sqlText,params SqlParameter[] parameters)
        {
            using (SqlConnection con = new SqlConnection(GetConnectionString()))
            {
                using (SqlCommand cmd = con.CreateCommand())
                {
                    con.Open();
                    cmd.CommandText = sqlText;
                    cmd.Parameters.AddRange(parameters.ToArray());
                    return cmd.ExecuteScalar();
                }
            }
        }
        #endregion

        #region 封装一个执行SQL返回一个DataTable
        public static DataTable ExecuteDataTable(string sqlText,params SqlParameter[] parameters)
        {
            using (SqlDataAdapter adapter = new SqlDataAdapter(sqlText,GetConnectionString()))
            {
                
                DataTable dt = new DataTable();
                adapter.SelectCommand.Parameters.AddRange(parameters.ToArray());
                adapter.Fill(dt);
                return dt;
            }
        }
        #endregion

        #region 封装一个执行SQL返回一个SqlDataReader
        public static SqlDataReader ExecutedReader(string sqlText,params SqlParameter[] parameters)
        {
            //SqlDataReader要求独占SqlConnection对象，并且SqlConnection必须是Open状态
            SqlConnection con = new SqlConnection(GetConnectionString());
            con.Open();
            SqlCommand cmd = con.CreateCommand();
            cmd.CommandText = sqlText;
            cmd.Parameters.AddRange(parameters.ToArray());
            //SqlDataReader执行完成后顺便关闭数据库连接
            return cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        #endregion
    }
}

三、数据表映射StudentInfo帮助类

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DataAdapterExample
{
    public class StudentInfo
    {
        public int stuId { get; set; }
        public string stuName { get; set; }
        public string stuSex { get; set; }
        public string stuBirthdate { get; set; }
        public string stuPhone { get; set; }
    }
}

四、主窗体对数据表进行CURD

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Configuration;
using System.Data.SqlClient;

namespace DataAdapterExample
{
    public partial class MainFrm : Form
    {
        //标识正在修改的数据行的主键
        private int updateStudentId = 0;
        public MainFrm()
        {
            InitializeComponent();
        }

        //主窗体加载数据
        private void MainFrm_Load(object sender, EventArgs e)
        {
            LoadStudentInfo();
        }
        //增加数据
        private void ButtonAdd_Click(object sender, EventArgs e)
        {
            using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            {
                con.Open();
                using (SqlCommand cmd = con.CreateCommand())
                {
                    cmd.CommandText = "insert into TableStudent (stuName,stuPhone,stuBirthdate,stuSex) values (@stuName,@stuPhone,@stuBirthdate,@stuSex)";
                    cmd.Parameters.AddWithValue("@stuName", this.textBoxstuName.Text.Trim());
                    cmd.Parameters.AddWithValue("@stuPhone", this.textBoxstuPhone.Text.Trim());
                    cmd.Parameters.AddWithValue("@stuSex", this.textBoxstuSex.Text.Trim());
                    cmd.Parameters.AddWithValue("@stuBirthdate", this.textBoxstuBirthdate.Text.Trim());
                    if (cmd.ExecuteNonQuery() > 0)
                    {
                        MessageBox.Show("增加数据成功！");
                    }

                }
            }
            LoadStudentInfo();
        }

        //删除数据
        private void ButtonDelete_Click(object sender, EventArgs e)
        {
            if (this.dataGridViewFromAdapter.SelectedRows.Count <= 0)
            {
                MessageBox.Show("请选择要删除的数据");
            }
            if (MessageBox.Show("确认要删除吗？", "提醒消息", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) != DialogResult.Yes)
            {
                return;
            }
            int deleteStuId = int.Parse(this.dataGridViewFromAdapter.SelectedRows[0].Cells["stuId"].Value.ToString());

            #region 原生手写
            //using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            //{
            //    con.Open();
            //    string sql = "delete from TableStudent where stuId=@stuId";
            //    using (SqlCommand cmd = con.CreateCommand())
            //    {
            //        cmd.CommandText = sql;
            //        cmd.Parameters.AddWithValue("stuId", deleteStuId);

            //        //cmd.Parameters.Add("@stuId", SqlDbType.Int);
            //        //cmd.Parameters["stuId"].Value = deleteStuId;

            //        //SqlParameter parameter = new SqlParameter();
            //        //parameter.ParameterName = "@stuId";
            //        //parameter.Value = deleteStuId;
            //        //cmd.Parameters.Add(parameter);


            //        if (cmd.ExecuteNonQuery() > 0)
            //        {
            //            MessageBox.Show("删除成功");
            //        }
            //    }
            //} 
            #endregion
            #region sqlHelper封装方法ExecuteNoQuery
            string strSQL = "delete from TableStudent where stuId=@stuId";
            int num = sqlHelper.ExecuteNoQuery(strSQL, new SqlParameter("@stuId", (object)deleteStuId));
            if (num>0)
            {
                MessageBox.Show("删除成功");
            }
            #endregion
            LoadStudentInfo();
        }

        //修改数据
        private void buttonUpdate_Click(object sender, EventArgs e)
        {
            using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            {
                using (SqlCommand cmd = con.CreateCommand())
                {
                    con.Open();
                    cmd.CommandText = "update TableStudent set stuName=@stuName,stuSex=@stuSex,stuBirthdate=@stuBirthdate,stuPhone=@stuPhone where stuId=@stuId";
                    cmd.Parameters.AddWithValue("@stuName", this.textBoxstuName.Text);
                    cmd.Parameters.AddWithValue("@stuBirthdate", this.textBoxstuBirthdate.Text);
                    cmd.Parameters.AddWithValue("@stuSex", this.textBoxstuSex.Text);
                    cmd.Parameters.AddWithValue("@stuPhone", this.textBoxstuPhone.Text);
                    cmd.Parameters.AddWithValue("@stuId", this.updateStudentId);
                    if (cmd.ExecuteNonQuery() > 0)
                    {
                        MessageBox.Show("更新数据成功");
                    }
                }
            }
            //刷新数据
            ButtonSearch_Click(this,null);
        }

        //选中数据赋值到对应文本框
        private void dataGridViewFromAdapter_SelectionChanged(object sender, EventArgs e)
        {
            if (this.dataGridViewFromAdapter.SelectedRows.Count <= 0)
            {
                //MessageBox.Show("请先选中数据");
                return;
            }
            //选中行的Id
            int selectedId = int.Parse(this.dataGridViewFromAdapter.SelectedRows[0].Cells["stuId"].Value.ToString());
            //把要修改的数据行的ID放到当前窗体的updateStudentId字段中保存
            updateStudentId = selectedId;
            using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            {
                con.Open();

                using (SqlCommand cmd = con.CreateCommand())
                {
                    cmd.CommandText = "select stuId,stuName,stuSex,stuBirthdate,stuPhone from TableStudent where stuId=@stuId";
                    cmd.Parameters.AddWithValue("@stuId", selectedId);
                    using (SqlDataReader reader = cmd.ExecuteReader())
                    {
                        if (reader.Read())
                        {
                            this.textBoxstuSex.Text = reader["stuSex"].ToString().Trim();
                            this.textBoxstuName.Text = reader["stuName"].ToString().Trim();
                            this.textBoxstuBirthdate.Text = reader["stuBirthdate"].ToString().Trim();
                            this.textBoxstuPhone.Text = reader["stuPhone"].ToString().Trim();
                        }
                    }
                }
            }
        }

        //双击弹出修改窗体
        private void dataGridViewFromAdapter_DoubleClick(object sender, EventArgs e)
        {
            if (this.dataGridViewFromAdapter.SelectedRows.Count <= 0)
            {
                return;
            }
            int editStuId = int.Parse(this.dataGridViewFromAdapter.SelectedRows[0].Cells["stuId"].Value.ToString());
            EditStudentForm editStuFrm = new EditStudentForm(new StudentInfo() { stuId = editStuId });
            //注册弹出窗体的关闭事件
            editStuFrm.FormClosing += EditStuFrm_FormClosing;
            editStuFrm.Show();
        }


        //弹出窗体修改完成关闭的时候执行的操作
        private void EditStuFrm_FormClosing(object sender, FormClosingEventArgs e)
        {
            LoadStudentInfo();
        }

        //多条件查询
        private void ButtonSearch_Click(object sender, EventArgs e)
        {

            //拼接whereSqlText脚本
            string whereSqlText = "select stuId,stuName,stuPhone,stuBirthdate,stuSex from TableStudent";
            List whereList = new List();
            List parameters = new List();
            if (!string.IsNullOrEmpty(this.textBoxSearchName.Text.Trim()))
            {
                //把where条件添加到whereList集合中
                whereList.Add("stuName like @stuName");
                SqlParameter parameter = new SqlParameter();
                parameter.ParameterName = "@stuName";
                parameter.Value = "%" + this.textBoxSearchName.Text.Trim() + "%";
                parameters.Add(parameter);
            }
            if (!string.IsNullOrEmpty(this.textBoxSearchSex.Text.Trim()))
            {
                //把where条件添加到whereList集合中
                whereList.Add("stuSex like @stuSex");
                SqlParameter parameter = new SqlParameter();
                parameter.ParameterName = "@stuSex";
                parameter.Value = "%" + this.textBoxSearchSex.Text.Trim() + "%";
                parameters.Add(parameter);

            }
            if (whereList.Count > 0)
            {
                whereSqlText += " where " + string.Join(" and ", whereList);
                //MessageBox.Show(whereSqlText);
                
            }
            //加载数据方法的调用
            LoadStudentInfo2DataGridView(whereSqlText, parameters.ToArray());
            
        }

        //加载数据
        private void LoadStudentInfo()
        {
            List studentInfoList = new List();
            string sqlText = "select stuId,stuName,stuSex,stuBirthdate,stuPhone from TableStudent";
            LoadStudentInfo2DataGridView(sqlText);
        }

        //加载数据方法的封装
        public void LoadStudentInfo2DataGridView(string sqlText,params SqlParameter[] parameters)
        {
            List studentInfoList = new List();
            #region 原生写法
            //using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            //{
            //    using (SqlDataAdapter adapter = new SqlDataAdapter(sqlText, con))
            //    {
            //        //填充之前，给SelectCommand赋参数
            //        adapter.SelectCommand.Parameters.AddRange(parameters.ToArray());
            //        DataTable dt = new DataTable();
            //        adapter.Fill(dt);
            //        foreach (DataRow row in dt.Rows)
            //        {
            //            StudentInfo studentInfo = new StudentInfo();
            //            studentInfo.stuId = int.Parse(row["stuId"].ToString().Trim());
            //            studentInfo.stuName = row["stuName"].ToString().Trim();
            //            studentInfo.stuSex = row["stuSex"].ToString().Trim();
            //            studentInfo.stuBirthdate = row["stuBirthdate"].ToString().Trim();
            //            studentInfo.stuPhone = row["stuPhone"].ToString().Trim();
            //            studentInfoList.Add(studentInfo);
            //        }

            //        this.dataGridViewFromAdapter.DataSource = studentInfoList;
            //    }
            //}
            #endregion

            #region sqlHelper类的ExecuteDataTable方法
            DataTable dt = sqlHelper.ExecuteDataTable(sqlText, parameters);
            foreach (DataRow row in dt.Rows)
            {
                StudentInfo studentInfo = new StudentInfo();
                studentInfo.stuId = int.Parse(row["stuId"].ToString().Trim());
                studentInfo.stuName = row["stuName"].ToString().Trim();
                studentInfo.stuSex = row["stuSex"].ToString().Trim();
                studentInfo.stuBirthdate = row["stuBirthdate"].ToString().Trim();
                studentInfo.stuPhone = row["stuPhone"].ToString().Trim();
                studentInfoList.Add(studentInfo);
            }

            this.dataGridViewFromAdapter.DataSource = studentInfoList;
            #endregion
        }


    }
}

五、双击DataGridView选中行弹出子窗体EditStudentForm对数据可以进行修改

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace DataAdapterExample
{
    public partial class EditStudentForm : Form
    {
        //窗体属性
        public StudentInfo StuInfo { get; set; }

        //构造函数接收StudentInfo对象
        public EditStudentForm(StudentInfo stuInfo)
        {
            InitializeComponent();
            //将传递的对象赋值给当前对象的属性
            StuInfo = stuInfo;
        }

        //弹出窗体的时候加载传递行stuId对应的数据到对应文本框
        private void EditStudentForm_Load(object sender, EventArgs e)
        {
            #region 原生写法
            //using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            //{

            //    using (SqlCommand cmd = con.CreateCommand())
            //    {
            //        con.Open();
            //        cmd.CommandText = "select stuSex,stuName,stuBirthdate,stuPhone from TableStudent where stuId=@stuId";
            //        cmd.Parameters.AddWithValue("@stuId", StuInfo.stuId);
            //        using (SqlDataReader reader = cmd.ExecuteReader())
            //        {
            //            if (reader.Read())
            //            {
            //                this.textBoxstuBirthdate.Text = reader["stuBirthdate"].ToString().Trim();
            //                this.textBoxstuName.Text = reader["stuName"].ToString().Trim();
            //                this.textBoxstuPhone.Text = reader["stuPhone"].ToString().Trim();
            //                this.textBoxstuSex.Text = reader["stuSex"].ToString().Trim();
            //            }
            //        }
            //    }

            //} 
            #endregion

            #region sqlHelper类的ExecuteReader方法
            string strSQL = "select stuSex,stuName,stuBirthdate,stuPhone from TableStudent where stuId=@stuId";
            using (SqlDataReader reader = sqlHelper.ExecutedReader(strSQL, new SqlParameter("@stuId", (object)StuInfo.stuId)))
            {

                if (reader.Read())
                {
                    this.textBoxstuBirthdate.Text = reader["stuBirthdate"].ToString().Trim();
                    this.textBoxstuName.Text = reader["stuName"].ToString().Trim();
                    this.textBoxstuPhone.Text = reader["stuPhone"].ToString().Trim();
                    this.textBoxstuSex.Text = reader["stuSex"].ToString().Trim();
                }
            } 
            #endregion
        }

        //保存更新
        private void ButtonSave_Click(object sender, EventArgs e)
        {
            #region 原生写法
            //using (SqlConnection con = new SqlConnection(sqlHelper.GetConnectionString()))
            //{
            //    using (SqlCommand cmd = con.CreateCommand())
            //    {
            //        con.Open();
            //        cmd.CommandText = "update TableStudent set stuPhone=@stuPhone,stuName=@stuName,stuBirthdate=@stuBirthdate,stuSex=@stuSex where stuId=@stuId";
            //        cmd.Parameters.AddWithValue("@stuId", StuInfo.stuId);
            //        cmd.Parameters.AddWithValue("@stuName", this.textBoxstuName.Text.Trim());
            //        cmd.Parameters.AddWithValue("@stuBirthdate", this.textBoxstuBirthdate.Text.Trim());
            //        cmd.Parameters.AddWithValue("@stuPhone", this.textBoxstuPhone.Text.Trim());
            //        cmd.Parameters.AddWithValue("@stuSex", this.textBoxstuSex.Text.Trim());
            //        if (cmd.ExecuteNonQuery() > 0)
            //        {
            //            MessageBox.Show("更新成功");
            //        }
            //        //关闭窗体
            //        this.Close();
            //    }
            //} 
            #endregion
            
            #region 使用sqlHelper类的ExecuteNoQuery静态方法
            string strSQL = "update TableStudent set stuPhone=@stuPhone,stuName=@stuName,stuBirthdate=@stuBirthdate,stuSex=@stuSex where stuId=@stuId";
            List parameterList = new List();

            SqlParameter paraStuName = new SqlParameter("@stuName", SqlDbType.NVarChar, 32);
            paraStuName.Value = this.textBoxstuName.Text.Trim();
            parameterList.Add(paraStuName);

            SqlParameter paraStuSex = new SqlParameter("@stuSex", SqlDbType.NVarChar, 32);
            paraStuSex.Value = this.textBoxstuSex.Text.Trim();
            parameterList.Add(paraStuSex);

            SqlParameter paraStuBirthdate = new SqlParameter("@stuBirthdate", SqlDbType.NVarChar, 32);
            paraStuBirthdate.Value = this.textBoxstuBirthdate.Text.Trim();
            parameterList.Add(paraStuBirthdate);

            SqlParameter paraStuPhone = new SqlParameter("@stuPhone", SqlDbType.NVarChar, 32);
            paraStuPhone.Value = this.textBoxstuPhone.Text.Trim();
            parameterList.Add(paraStuPhone);

            SqlParameter paraStuId = new SqlParameter("@stuId", SqlDbType.NVarChar, 32);
            paraStuId.Value = StuInfo.stuId;
            parameterList.Add(paraStuId);

            int num = sqlHelper.ExecuteNoQuery(strSQL, parameterList.ToArray());
            if (num > 0)
            {
                MessageBox.Show("保存更新成功！");
            }
            //关闭窗口
            this.Close(); 
            #endregion
        }

    }
}

主窗体最下面的文本框功能：

（1）增加新的数据行
（2）显示选中行数据
（3）修改选中行数据

优化：sqlHelper类中封装方法

（1）执行SQL返回受影响的行数的ExecuteNoQuery方法
（2）执行SQL返回查询结果中第一行第一列的值的ExecuteScalar方法
（3）执行SQL返回一个DataTable的ExecuteDataTable方法
（4）执行SQL返回一个SqlDataReader的ExecutedReader方法