C#--C/S--学员管理系统--7--学员信息的增删改查

以下是学习笔记：

一,添加新学员

1，后台部分：在DAL---StudentService中添加代码

        /// <summary>
        /// 判断当前身份证号是否已经存在
        /// </summary>
        /// <param name="studentIdNo"></param>
        /// <returns></returns>
        public bool IsIdNoExisted(string studentIdNo)
        {
            string sql = "select count(*) from Students where StudentIdNo={0}";
            sql = string.Format(sql, studentIdNo);
            int result = Convert.ToInt32(SQLHelper.GetSingleResult(sql));
            if (result == 1) return true;
            else return false;
        }
        /// <summary>
        /// 添加学员
        /// </summary>
        /// <param name="objStudent"></param>
        /// <returns></returns>
        public int AddStudent(Student objStudent)
        {            
            //【1】编写SQL语句
            StringBuilder sqlBuilder = new StringBuilder();//如果字符串比较长，可以用StringBuilder
            sqlBuilder.Append("insert into Students(StudentName,Gender,Birthday,StudentIdNo,Age,PhoneNumber,StudentAddress,CardNo,ClassId)");
            sqlBuilder.Append("  values('{0}','{1}','{2}',{3},{4},'{5}','{6}','{7}',{8})");
            //【2】解析对象
            string sql = string.Format(sqlBuilder.ToString(),
               objStudent.StudentName, objStudent.Gender, objStudent.Birthday.ToString("yyyy-MM-dd"),
               objStudent.StudentIdNo, objStudent.Age, objStudent.PhoneNumber,
               objStudent.StudentAddress, objStudent.CardNo, objStudent.ClassId);
            //【3】提交到数据库
            try
            {
                return SQLHelper.Update(sql);
            }
            catch (SqlException ex)
            {
                throw new Exception("数据库操作出现异常！具体信息：" + ex.Message);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

　2，UI部分　

 确认添加的按钮事件

        private void btnAdd_Click(object sender, EventArgs e)
        {
            #region  验证数据

            if (this.txtStudentName.Text.Trim().Length == 0)
            {
                MessageBox.Show("学生姓名不能为空！", "提示信息");
                this.txtStudentName.Focus();
                return;
            }
            if (this.txtCardNo.Text.Trim().Length == 0)
            {
                MessageBox.Show("考勤卡号不能为空！", "提示信息");
                this.txtCardNo.Focus();
                return;
            }
            //验证性别
            if (!this.rdoFemale.Checked && !this.rdoMale.Checked)
            {
                MessageBox.Show("请选择学生性别！", "提示信息");
                return;
            }
            //验证班级
            if (this.cboClassName.SelectedIndex == -1)
            {
                MessageBox.Show("请选择班级！", "提示信息");
                return;
            }
            //验证身份证号是否符合要求
            if (!Common.DataValidate.IsIdentityCard(this.txtStudentIdNo.Text.Trim()))
            {
                MessageBox.Show("身份证号不符合要求！", "验证提示");
                this.txtStudentIdNo.Focus();
                return;
            }
            //验证身份证号是否重复
            if (objStudentService.IsIdNoExisted(this.txtStudentIdNo.Text.Trim()))
            {
                MessageBox.Show("身份证号不能和现有学员身份证号重复！", "验证提示");
                this.txtStudentIdNo.Focus();
                this.txtStudentIdNo.SelectAll();
                return;
            }
            //验证身份证号是否和出生日期相吻合
            string month = string.Empty;
            string day = string.Empty;
            if (Convert.ToDateTime(this.dtpBirthday.Text).Month < 10)
                month = "0" + Convert.ToDateTime(this.dtpBirthday.Text).Month;
            else
                month = Convert.ToDateTime(this.dtpBirthday.Text).Month.ToString();
            if (Convert.ToDateTime(this.dtpBirthday.Text).Day < 10)
                day = "0" + Convert.ToDateTime(this.dtpBirthday.Text).Day;
            else
                day = Convert.ToDateTime(this.dtpBirthday.Text).Day.ToString();
            string birthday = Convert.ToDateTime(this.dtpBirthday.Text).Year.ToString() + month + day;

            if (!this.txtStudentIdNo.Text.Trim().Contains(birthday))
            {
                MessageBox.Show("身份证号和出生日期不匹配！", "验证提示");
                this.txtStudentIdNo.Focus();
                this.txtStudentIdNo.SelectAll();
                return;
            }
            //验证出生日期
            int age = DateTime.Now.Year - Convert.ToDateTime(this.dtpBirthday.Text).Year;
            if (age < 18)
            {
                MessageBox.Show("学生年龄不能小于18岁！", "验证提示");
                return;
            }
            #endregion

            #region 封装学生对象

            Student objStudent = new Student()
            {
                StudentName = this.txtStudentName.Text.Trim(),
                Gender = this.rdoMale.Checked ? "男" : "女",
                Birthday = Convert.ToDateTime(this.dtpBirthday.Text),
                StudentIdNo = this.txtStudentIdNo.Text.Trim(),
                PhoneNumber = this.txtPhoneNumber.Text.Trim(),
                StudentAddress = this.txtAddress.Text.Trim(),
                CardNo = this.txtCardNo.Text.Trim(),
                ClassId = Convert.ToInt32(this.cboClassName.SelectedValue),//获取选择班级对应的ClassId
                Age = DateTime.Now.Year - Convert.ToDateTime(this.dtpBirthday.Text).Year
            };

            #endregion

            #region 调用后台数据访问方法添加对象

            try
            {
                if (objStudentService.AddStudent(objStudent) == 1)
                {
                    DialogResult result = MessageBox.Show("新学员添加成功！是否继续添加？", "提示信息", MessageBoxButtons.YesNo,
                        MessageBoxIcon.Question);
                    if (result == DialogResult.Yes)//清空用户的输入
                    {
                        this.cboClassName.SelectedIndex = -1;
                        this.rdoFemale.Checked = false;
                        this.rdoMale.Checked = false;
                        //清除文本框
                        foreach (Control item in this.Controls)
                        {
                            if (item is TextBox)
                                item.Text = "";
                        }
                        this.txtStudentName.Focus();
                    }
                }
                else
                    this.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

            #endregion

        }

　二，学员信息查询

　1，Models中添加2个实体类 ：Models--Students 和扩展实体类Models--Ext-StudentExt

Students:

namespace Models
{
   /// <summary>
   /// 学员实体类
   /// </summary>
  public   class Student
    {
        public int StudentId { get; set; }
        public string StudentName { get; set; }
        public string Gender { get; set; }
        public DateTime Birthday{ get; set; }      
        //将数据库中的18位整数转换成字符串
        public string StudentIdNo { get; set; }
        public int Age { get; set; }
        public string PhoneNumber { get; set; }
        public string StudentAddress { get; set; }
        public string CardNo { get; set; }
        public int ClassId { get; set; }   
    }
}

　　StudentExt:

namespace Models
{
    /// <summary>
    /// 学员信息扩展实体
    /// </summary>
    public class StudentExt : Student
    {
        public string ClassName { get; set; }

        public int CSharp { get; set; }
        public int SQLServerDB { get; set; }
    }
}

　　2,在DAL--StudentService学员信息数访问类添加查询方法

        #region 查询学员【根据班级、学号、卡号】

        /// <summary>
        /// 根据班级名称查询学员信息
        /// </summary>
        /// <param name="className"></param>
        /// <returns></returns>
        public List<StudentExt> GetStudentByClass(string className)
        {
            string sql = "select StudentName,StudentId,Gender,Birthday,ClassName from Students";
            sql += " inner join StudentClass on Students.ClassId=StudentClass.ClassId";
            sql += " where ClassName='{0}'";
            sql = string.Format(sql, className);
            SqlDataReader objReader = SQLHelper.GetReader(sql);
            List<StudentExt> list = new List<StudentExt>();
            while (objReader.Read())
            {
                list.Add(new StudentExt()
                    {
                        StudentId = Convert.ToInt32(objReader["StudentId"]),
                        StudentName = objReader["StudentName"].ToString(),
                        Gender = objReader["Gender"].ToString(),
                        Birthday = Convert.ToDateTime(objReader["Birthday"]),
                        ClassName = objReader["ClassName"].ToString()
                    });
            }
            objReader.Close();
            return list;

        }
        /// <summary>
        ///根据学号查询学员对象
        /// </summary>
        /// <param name="studentId"></param>
        /// <returns></returns>
        public StudentExt GetStudentById(string studentId)
        {
            string sql = "select StudentId,StudentName,Gender,Birthday,ClassName,StudentIdNo,PhoneNumber,StudentAddress,CardNo from Students";
            sql += " inner join StudentClass on Students.ClassId=StudentClass.ClassId";
            sql += " where StudentId=" + studentId;
            SqlDataReader objReader = SQLHelper.GetReader(sql);
            StudentExt objStudent = null;
            if (objReader.Read())
            {
                objStudent = new StudentExt()
                {
                    StudentId = Convert.ToInt32(objReader["StudentId"]),
                    StudentName = objReader["StudentName"].ToString(),
                    Gender = objReader["Gender"].ToString(),
                    Birthday = Convert.ToDateTime(objReader["Birthday"]),
                    ClassName = objReader["ClassName"].ToString(),
                    CardNo = objReader["CardNo"].ToString(),
                    StudentIdNo = objReader["StudentIdNo"].ToString(),
                    PhoneNumber = objReader["PhoneNumber"].ToString(),
                    StudentAddress = objReader["StudentAddress"].ToString()
                };
            }
            objReader.Close();
            return objStudent;
        }

        /// <summary>
        /// 根据卡号查询学生信息（请思考如何将上面的方法合并，像下面的方法这么简单）
        /// </summary>
        /// <param name="CardNo"></param>
        /// <returns></returns>
        public StudentExt GetStudentByCardNo(string CardNo)
        {
            string whereSql = string.Format(" where CardNo='{0}'", CardNo);
            return this.GetStudent(whereSql);
        }
        private StudentExt GetStudent(string whereSql)
        {
            string sql = "select StudentId,StudentName,Gender,Birthday,ClassName,";
            sql += "StudentIdNo,PhoneNumber,StudentAddress,CardNo from Students";
            sql += " inner join StudentClass on Students.ClassId=StudentClass.ClassId ";
            sql += whereSql;
            SqlDataReader objReader = SQLHelper.GetReader(sql);
            StudentExt objStudent = null;
            if (objReader.Read())
            {
                objStudent = new StudentExt()
                {
                    StudentId = Convert.ToInt32(objReader["StudentId"]),
                    StudentName = objReader["StudentName"].ToString(),
                    Gender = objReader["Gender"].ToString(),
                    Birthday = Convert.ToDateTime(objReader["Birthday"]),
                    ClassName = objReader["ClassName"].ToString(),
                    CardNo = objReader["CardNo"].ToString(),
                    StudentIdNo = objReader["StudentIdNo"].ToString(),
                    PhoneNumber = objReader["PhoneNumber"].ToString(),
                    StudentAddress = objReader["StudentAddress"].ToString()
                };
            }
            objReader.Close();
            return objStudent;
        }
        #endregion

　　3，UI部分

 查询按钮事件代码：

        //按照班级查询
        private void btnQuery_Click(object sender, EventArgs e)
        {
            if (this.cboClass.SelectedIndex == -1)
            {
                MessageBox.Show("请选择班级！", "提示信息");
                return;
            }
            this.dgvStudentList.AutoGenerateColumns = false;//DataGridView中设置不显示未封装的属性
            //执行查询
            this.dgvStudentList.DataSource = objStuService.GetStudentByClass(this.cboClass.Text);

        }
        //根据学号查询
        private void btnQueryById_Click(object sender, EventArgs e)
        {
            if (this.txtStudentId.Text.Trim().Length == 0)
            {
                MessageBox.Show("请输入学号！", "提示信息");
                this.txtStudentId.Focus();
                return;
            }
            //进一步验证学号必须是数字（请使用正则表达式...）

            //执行查询
            StudentExt objStudent = objStuService.GetStudentById(this.txtStudentId.Text.Trim());
            if (objStudent == null)
            {
                MessageBox.Show("学员信息不存在！", "提示信息");
                this.txtStudentId.Focus();
            }
            else
            {
                //在学员详细信息窗体显示
                FrmStudentInfo objFrmStuInfo = new FrmStudentInfo(objStudent);
                objFrmStuInfo.Show();
            }
        }

　　学员信息显示：

学员信息显示代码：

    public partial class FrmStudentInfo : Form
    {
        public FrmStudentInfo()
        {
            InitializeComponent();
        }
        public FrmStudentInfo(StudentExt objStudent)
            : this()//调用默认的构造方法
        {
            //显示学员信息
            this.lblStudentName.Text = objStudent.StudentName;
            this.lblStudentIdNo.Text = objStudent.StudentIdNo;
            this.lblPhoneNumber .Text = objStudent.PhoneNumber;
            this.lblBirthday.Text = objStudent.Birthday.ToShortDateString();
            this.lblAddress.Text = objStudent.StudentAddress;
            this.lblGender.Text = objStudent.Gender;
            this.lblClass.Text = objStudent.ClassName;
            this.lblCardNo.Text = objStudent.CardNo;
        }
        //关闭
        private void btnClose_Click(object sender, EventArgs e)
        {
            this.Close();
        }
    }

　　三，学员信息修改

 1，后台代码：

在DAL--StudentService中添加修改学员对象的方法

        #region 修改学员对象

        /// <summary>
        /// 修改学员时判断身份证号是否和其他学员重复
        /// </summary>
        /// <param name="studentIdNo"></param>
        /// <param name="studentId"></param>
        /// <returns></returns>
        public bool IsIdNoExisted(string studentIdNo, string studentId)
        {
            string sql = "select count(*) from Students where StudentIdNo={0}  and StudentId<>{1}";
            sql = string.Format(sql, studentIdNo, studentId);
            int result = Convert.ToInt32(SQLHelper.GetSingleResult(sql));
            if (result == 1) return true;
            else return false;
        }

        /// <summary>
        /// 修改学员对象
        /// </summary>
        /// <param name="objStudent"></param>
        /// <returns></returns>
        public int ModifyStudent(Student objStudent)
        {
            StringBuilder sqlBuilder = new StringBuilder();
            sqlBuilder.Append("Update Students set StudentName='{0}',Gender='{1}',Birthday='{2}',");
            sqlBuilder.Append("StudentIdNo={3},Age={4},PhoneNumber='{5}',StudentAddress='{6}',CardNo='{7}',ClassId={8}");
            sqlBuilder.Append(" where StudentId={9}");//注意where前面有空格
            //解析对象
            string sql = string.Format(sqlBuilder.ToString(),
            objStudent.StudentName, objStudent.Gender, objStudent.Birthday,
            objStudent.StudentIdNo, objStudent.Age, objStudent.PhoneNumber,
            objStudent.StudentAddress, objStudent.CardNo, objStudent.ClassId, objStudent.StudentId);
            try
            {
                return SQLHelper.Update(sql);
            }
            catch (SqlException ex)
            {
                throw new Exception("数据库操作出现异常！具体信息：" + ex.Message);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        #endregion

　　2，前端UI点击修改代码的事件代码

 修改的代码：

        //修改学员对象
        private void btnEidt_Click(object sender, EventArgs e)
        {
            if (this.dgvStudentList.RowCount == 0)
            {
                MessageBox.Show("没有任何要修改的学信息！", "提示信息");
                return;
            }
            if (this.dgvStudentList.CurrentRow == null)//判断当前行
            {
                MessageBox.Show("请选中要修改的学员信息！", "提示信息");
                return;
            }
            //获取学号
            string studentId = this.dgvStudentList.CurrentRow.Cells["StudentId"].Value.ToString();
            //获取要修改的学员详细信息
            StudentExt objStudent = objStuService.GetStudentById(studentId);
            //显示要修改的学员信息窗口
            FrmEditStudent objEditStudent = new FrmEditStudent(objStudent);
            DialogResult result = objEditStudent.ShowDialog();
            //判断修改是否成
            if (result == DialogResult.OK)
            {
                btnQuery_Click(null, null);//同步刷新修改的信息（适合查询数据量小的情况）
            }

        }

　　3，修改学员信息的代码

通过构造函数把学员信息对象传过来

 提交修改的代码

        //提交修改
        private void btnModify_Click(object sender, EventArgs e)
        {
            #region 验证信息

            if (this.txtStudentName.Text.Trim().Length == 0)
            {
                MessageBox.Show("学生姓名不能为空！", "提示信息");
                this.txtStudentName.Focus();
                return;
            }
            //验证性别
            if (!this.rdoFemale.Checked && !this.rdoMale.Checked)
            {
                MessageBox.Show("请选择学生性别！", "提示信息");
                return;
            }
            //验证班级
            if (this.cboClassName.SelectedIndex == -1)
            {
                MessageBox.Show("请选择班级！", "提示信息");
                return;
            }
            //验证身份证号是否符合要求
            if (!Common.DataValidate.IsIdentityCard(this.txtStudentIdNo.Text.Trim()))
            {
                MessageBox.Show("身份证号不符合要求！", "验证提示");
                this.txtStudentIdNo.Focus();
                return;
            }
            //验证身份证号是否重复
            if (objStudentService.IsIdNoExisted(this.txtStudentIdNo.Text.Trim(), this.txtStudentId.Text.Trim()))
            {
                MessageBox.Show("身份证号不能和现有学员身份证号重复！", "验证提示");
                this.txtStudentIdNo.Focus();
                this.txtStudentIdNo.SelectAll();
                return;
            }
            //验证身份证号是否和出生日期相吻合
            string month = string.Empty;
            string day = string.Empty;
            if (Convert.ToDateTime(this.dtpBirthday.Text).Month < 10)
                month = "0" + Convert.ToDateTime(this.dtpBirthday.Text).Month;
            if (Convert.ToDateTime(this.dtpBirthday.Text).Day < 10)
                day = "0" + Convert.ToDateTime(this.dtpBirthday.Text).Day;
            string birthday = Convert.ToDateTime(this.dtpBirthday.Text).Year.ToString() + month + day;

            if (!this.txtStudentIdNo.Text.Trim().Contains(birthday))
            {
                MessageBox.Show("身份证号和出生日期不匹配！", "验证提示");
                this.txtStudentIdNo.Focus();
                this.txtStudentIdNo.SelectAll();
                return;
            }
            //验证出生日期
            int age = DateTime.Now.Year - Convert.ToDateTime(this.dtpBirthday.Text).Year;
            if (age < 18)
            {
                MessageBox.Show("学生年龄不能小于18岁！", "验证提示");
                return;
            }

            #endregion

            #region 封装学生对象

            Student objStudent = new Student()
            {
                StudentId = Convert.ToInt32(this.txtStudentId.Text.Trim()),
                StudentName = this.txtStudentName.Text.Trim(),
                Gender = this.rdoMale.Checked ? "男" : "女",
                Birthday = Convert.ToDateTime(this.dtpBirthday.Text),
                StudentIdNo = this.txtStudentIdNo.Text.Trim(),
                PhoneNumber = this.txtPhoneNumber.Text.Trim(),
                StudentAddress = this.txtAddress.Text.Trim(),
                CardNo = this.txtCardNo.Text.Trim(),
                ClassId = Convert.ToInt32(this.cboClassName.SelectedValue),//获取选择班级对应的ClassId
                Age = DateTime.Now.Year - Convert.ToDateTime(this.dtpBirthday.Text).Year
            };

            #endregion

            #region 提交修改

            try
            {
                if (objStudentService.ModifyStudent(objStudent) == 1)
                {
                    MessageBox.Show("学员信息修改成功！", "提示信息");           
                    this.DialogResult = DialogResult.OK;//返回修改成功的信息
                    this.Close();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

            #endregion
        }

　　4，优化用户体验，双击显示学员信息

        //双击选中的学员对象并显示详细信息
        private void dgvStudentList_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
        {
            if (this.dgvStudentList.CurrentRow != null)
            {
                string studentId = this.dgvStudentList.CurrentRow.Cells["StudentId"].Value.ToString();
                this.txtStudentId.Text = studentId;
                btnQueryById_Click(null, null);
            }
        }

　　5，优化用户体验，右键就可以修改（查看）学员信息，效果如下：

 1，添加contextMenuStrip控件

,2，设置DataGridView的ContextMenuStrip

 3，设置ContextMenuStrip的事件代码：

        //右键菜单的事件
        private void tsmiModifyStu_Click(object sender, EventArgs e)
        {
            btnEidt_Click(null, null);//修改学员对象按钮的事件
        }

　　四，删除学员信息

1，后台代码

在DAL--StudentService中添加删除学员对象的方法

        #region 删除学员对象

        public int DeleteStudentById(string studentId)
        {
            string sql = "delete from Students where StudentId=" + studentId;
            try
            {
                return SQLHelper.Update(sql);
            }
            catch (SqlException ex)
            {
                if (ex.Number == 547)
                    throw new Exception("该学号被其他数据表引用，不能直接删除该学员对象！");//判断外键引用
                else
                    throw new Exception("数据库操作出现异常！具体信息：" + ex.Message);
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

        #endregion

　　2，前端UI

 删除按钮的事件代码：

        //删除学员对象
        private void btnDel_Click(object sender, EventArgs e)
        {
            if (this.dgvStudentList.RowCount == 0)
            {
                MessageBox.Show("没有任何要删除的学信息！", "提示信息");
                return;
            }
            if (this.dgvStudentList.CurrentRow == null)
            {
                MessageBox.Show("请选中要删除的学员信息！", "提示信息");
                return;
            }
            //删除确认
            string studentName = this.dgvStudentList.CurrentRow.Cells["StudentName"].Value.ToString();
            DialogResult result = MessageBox.Show("确认要删除学员  [" + studentName + "]  吗？", "删除询问", MessageBoxButtons.OKCancel, MessageBoxIcon.Question);
            if (result == DialogResult.Cancel) return;
            //获取学号并删除
            string studentId = this.dgvStudentList.CurrentRow.Cells["StudentId"].Value.ToString();
            try
            {
                if (objStuService.DeleteStudentById(studentId) == 1)
                {
                    btnQuery_Click(null, null);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "提示信息");
            }
        }