生命之长短殊不重要，只要你活得快乐，在有生之年做些有意义的事，便已足够。

实体类：

public class clsModel
    {
        protected SQLiteConnection conn;

        public clsModel(SQLiteConnection @conn)
        {
            this.conn = @conn;

            if (this.conn != null && 
                this.conn.State.ToString() == "Closed")
            {
                conn.Open();
            }
        }
    }

public class clsStudents : clsModel
    {
        public clsStudents(SQLiteConnection @conn) : base(@conn) { }

        public DataTable getAllStudents()
        {
            DataTable dt = new DataTable();
            SQLiteCommand command = conn.CreateCommand();
            command.CommandText = "SELECT * FROM Students";
            SQLiteDataAdapter db = new SQLiteDataAdapter(command);
            db.Fill(dt);
            return dt;
        }

        public DataTable getStudent(String @studentID)
        {
            DataTable dt = new DataTable();
            SQLiteCommand command = conn.CreateCommand();
            command.CommandText = "SELECT * FROM Students WHERE studentID = @studentID";
            //为了防止SQL注入，所有的用户输入将进行参数设置。
            command.Parameters.Add(new SQLiteParameter("@studentID",@studentID));
            SQLiteDataAdapter db = new SQLiteDataAdapter(command);
            db.Fill(dt);
            return dt;
        }

        public void insertStudent(String @firstName,String @lastName)
        {
            SQLiteCommand command = conn.CreateCommand();
            command.CommandText = "INSERT into Students (firstName,lastName) VALUES(@firstName,@lastName)";
            command.Parameters.Add(new SQLiteParameter("@firstName",@firstName));
            command.Parameters.Add(new SQLiteParameter("@lastName",@lastName));
            command.ExecuteNonQuery();
        }

        public void updateStudent(String @studentID,String @firstName,String @lastName)
        {
            SQLiteCommand command = conn.CreateCommand();
            command.CommandText = "UPDATE Students SET firstName = @firstName,lastName = @lastName WHERE studentID = @studentID";
            command.Parameters.Add(new SQLiteParameter("@studentID",@studentID));
            command.Parameters.Add(new SQLiteParameter("@firstName",@lastName));
            command.ExecuteNonQuery();
        }

        public void deleteStudent(String @studentID)
        {
            SQLiteCommand command = conn.CreateCommand();
            command.CommandText = "DELETE FROM Students WHERE studentID = @studentID";
            command.Parameters.Add(new SQLiteParameter("@studentID",@studentID));
            command.ExecuteNonQuery();
        }

    }

Form1窗体后台代码:

ublic partial class Form1 : Form
    {
        SQLiteConnection conn;
        clsStudents students;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender,EventArgs e)
        {
            conn = new SQLiteConnection(@"data source = ....testdb.db");
            students = new clsStudents(conn);
            dataGridView1.DataSource = students.getAllStudents();
        }

        private void btnAdd_Click(object sender,EventArgs e)
        {
            new Form2(students).ShowDialog();
            loadGridView();
        }

        private void btnEdit_Click(object sender,EventArgs e)
        {
            int index = dataGridView1.CurrentCell.RowIndex;
            if (index > -1)
            {
                String studentID = dataGridView1.Rows[index].Cells["studentID"].Value.ToString();
                new Form2(students,studentID).ShowDialog();
                loadGridView();
            }
        }

        private void btnDelete_Click(object sender,EventArgs e)
        {

            int index = dataGridView1.CurrentCell.RowIndex;
            if (index > -1)
            {
                String studentID = dataGridView1.Rows[index].Cells["studentID"].Value.ToString();
                var results = MessageBox.Show("你确定要删除此记录?","删除学生",MessageBoxButtons.YesNo,MessageBoxIcon.Question);
                if (results == DialogResult.Yes)
                {
                    students.deleteStudent(studentID);
                    loadGridView();
                }
            }
        }

        private void loadGridView()
        {
            dataGridView1.DataSource = students.getAllStudents();
        }

        private void btnExit_Click(object sender,EventArgs e)
        {
            this.Close();
        }
    }

Form1窗体后台代码:

public partial class Form2 : Form
    {
        clsStudents students;
        String studentID = "";

        //Add Mode
        public Form2(clsStudents @students)
        {
            init(@students);
            lblStudentID.Text = "新的学生实体";
        }

        //Edit Mode
        public Form2(clsStudents @students,String studentID)
        {
            init(@students);
            this.studentID = studentID;
            lblStudentID.Text = this.studentID;
            DataTable dt = students.getStudent(studentID);
            txtFirstName.Text = dt.Rows[0]["firstName"].ToString();
            txtLastName.Text  = dt.Rows[0]["lastName"].ToString();
        }

        private void init(clsStudents students)
        {
            InitializeComponent();
            this.students = students;
        }


        private void btnOK_Click(object sender,EventArgs e)
        {
            if (studentID == String.Empty)
            {
                //Add Mode
                students.insertStudent(txtFirstName.Text.Trim(),txtLastName.Text.Trim());
            }
            else
            {
                //Edit Mode
                students.updateStudent(this.studentID,txtFirstName.Text.Trim(),txtLastName.Text.Trim());
            }

            this.Close();
        }

        private void btnCancel_Click(object sender,EventArgs e)
        {
            this.Close();
        }
    }

运行结果如图:

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（编辑：李大同）

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