วิธีเอาข้อมูล dateTimePicker1 ลงใน MySql ทำยังงัยบ้างครับ ผมทำหลายวิธีแล้วยังไม่ได้เลย แก้ยังงัยมันกะยังเป็นค่า Null อยุ่ครับ C# น่ะครับ

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using MySql.Data.MySqlClient;

namespace DEMO
{
    public partial class FormSave_1_3 : Form
    {
        MySqlConnection objConn = new MySqlConnection();
        MySqlCommand objCmd = new MySqlCommand();
      

        public FormSave_1_3()
        {
            InitializeComponent();
        }

        private void home_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormHome f = new FormHome();
            f.Show();
        }

        private void personal_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport f = new FormReport();
            f.Show();
        }

        private void employee_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave f = new FormSave();
            f.Show();
        }

        private void hometax_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSystem f = new FormSystem();
            f.Show();
        }

        private void toolStripMenuItem1_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("Are you sure to exit?", "Confirm.", MessageBoxButtons.YesNo, MessageBoxIcon.Question, MessageBoxDefaultButton.Button1) == DialogResult.Yes)
            {
                Application.Exit();
            }
        }

        private void นกเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_1_1 f = new FormReport_1_1();
            f.Show();
        }

        private void บญชรายชอนกเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_1_2 f = new FormReport_1_2();
            f.Show();
        }

        private void ครToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_1_3 f = new FormReport_1_3();
            f.Show();
        }

        private void บญชรายชอครToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_1_4 f = new FormReport_1_4();
            f.Show();
        }

        private void อนมตจบToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_1_5 f = new FormReport_1_5();
            f.Show();
        }

        private void ตรวจสอบจบToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_1_6 f = new FormReport_1_6();
            f.Show();
        }

        private void ทะเบยนเรยนรายหองToolStripMenuItem_Click(object sender, EventArgs e)
        {

            this.Hide();
            FormRePort_2_1 f = new FormRePort_2_1();
            f.Show();
        }

        private void ทะเบยนเรยนรายบคคลToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormRePort_2_2 f = new FormRePort_2_2();
            f.Show();
        }

        private void ทToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormRePort_2_3 f = new FormRePort_2_3();
            f.Show();
        }

        private void ทะเบยนเรยนรายผสอนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormRePort_2_4 f = new FormRePort_2_4();
            f.Show();
        }

        private void วชาเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormRePort_2_5 f = new FormRePort_2_5();
            f.Show();
        }

        private void แผนการเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormRePort_2_6 f = new FormRePort_2_6();
            f.Show();
        }

        private void ใบแจงผลการเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_1 f = new FormReport_3_1();
            f.Show();
        }

        private void แบบประกาศผลการเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_2 f = new FormReport_3_2();
            f.Show();
        }

        private void รายชอผทตด0รมสรายชนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_3 f = new FormReport_3_3();
            f.Show();
        }

        private void รายชอผทตด0รมสรายวชาToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_4 f = new FormReport_3_4();
            f.Show();
        }

        private void รายชอผทตด0รมสในชวงปToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_5 f = new FormReport_3_5();
            f.Show();
        }

        private void รายชอผทไมผานกจกรรมToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_6 f = new FormReport_3_6();
            f.Show();
        }

        private void ประเมนคณToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_7 f = new FormReport_3_7();
            f.Show();
        }

        private void ใบคำรองขอสอบแกตวToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_8 f = new FormReport_3_8();
            f.Show();
        }

        private void ผลการเรยนรายปToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_9 f = new FormReport_3_9();
            f.Show();
        }

        private void ผลการเรยนตลอดหลกสตรToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_3_10 f = new FormReport_3_10();
            f.Show();
        }

        private void ระเบยนผลการเรยนปพ1ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_4_1 f = new FormReport_4_1();
            f.Show();
        }

        private void ประกาศนยบตรปพ2ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_4_2 f = new FormReport_4_2();
            f.Show();
        }

        private void แบบรายงานผจบการศToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_4_3 f = new FormReport_4_3();
            f.Show();
        }

        private void ใบรบรองผลการศกษาปพ7ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_4_4 f = new FormReport_4_4();
            f.Show();
        }

        private void ตรวจสอบขอมลปพ3ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_4_5 f = new FormReport_4_5();
            f.Show();
        }

        private void สรปผลการเรยนเฉลยGPAToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_5_1 f = new FormReport_5_1();
            f.Show();
        }

        private void สรปผลการเรยนรายชนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_5_2 f = new FormReport_5_2();
            f.Show();
        }

        private void สรปผลการเรยนรายวชาToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_5_3 f = new FormReport_5_3();
            f.Show();
        }

        private void สรปผลการเรยนสงสดตำสดToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_5_4 f = new FormReport_5_4();
            f.Show();
        }

        private void สรปผลการจบหลกสตรToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_5_5 f = new FormReport_5_5();
            f.Show();
        }

        private void จำนวนนกเรยนรายชนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_6_1 f = new FormReport_6_1();
            f.Show();
        }

        private void จำนวนนกเรยนรายอายToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_6_2 f = new FormReport_6_2();
            f.Show();
        }

        private void ผลสมฤทธทางการเรยนรายวชาToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_6_3 f = new FormReport_6_3();
            f.Show();
        }

        private void ผลสมฤทธทางการเรยนรายกลมสาระฯToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormReport_6_4 f = new FormReport_6_4();
            f.Show();
        }

        private void toolStripMenuItem6_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_1_1 f = new FormSave_1_1();
            f.Show();
        }

        private void toolStripMenuItem7_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_1_2 f = new FormSave_1_2();
            f.Show();
        }

        private void toolStripMenuItem8_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_1_3 f = new FormSave_1_3();
            f.Show();
        }

        private void toolStripMenuItem9_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_1_4 f = new FormSave_1_4();
            f.Show();
        }

        private void toolStripMenuItem10_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_1_5 f = new FormSave_1_5();
            f.Show();
        }

        private void toolStripMenuItem11_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_1_6 f = new FormSave_1_6();
            f.Show();
        }

        private void toolStripMenuItem13_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_2_1 f = new FormSave_2_1();
            f.Show();
        }

        private void toolStripMenuItem14_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_2_2 f = new FormSave_2_2();
            f.Show();
        }

        private void toolStripMenuItem15_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_2_3 f = new FormSave_2_3();
            f.Show();
        }

        private void toolStripMenuItem16_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_2_4 f = new FormSave_2_4();
            f.Show();
        }

        private void toolStripMenuItem17_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_2_5 f = new FormSave_2_5();
            f.Show();
        }

        private void toolStripMenuItem18_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_2_6 f = new FormSave_2_6();
            f.Show();
        }

        private void toolStripMenuItem20_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_1 f = new FormSave_3_1();
            f.Show();
        }

        private void toolStripMenuItem21_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_2 f = new FormSave_3_2();
            f.Show();
        }

        private void toolStripMenuItem22_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_3 f = new FormSave_3_3();
            f.Show();
        }

        private void toolStripMenuItem23_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_4 f = new FormSave_3_4();
            f.Show();
        }

        private void toolStripMenuItem24_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_5 f = new FormSave_3_5();
            f.Show();
        }

        private void toolStripMenuItem25_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_6 f = new FormSave_3_6();
            f.Show();
        }

        private void toolStripMenuItem26_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_7 f = new FormSave_3_7();
            f.Show();
        }

        private void toolStripMenuItem27_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_8 f = new FormSave_3_8();
            f.Show();
        }

        private void toolStripMenuItem28_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_9 f = new FormSave_3_9();
            f.Show();
        }

        private void toolStripMenuItem29_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_3_10 f = new FormSave_3_10();
            f.Show();
        }

        private void รหสวชาToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_4_1 f = new FormSave_4_1();
            f.Show();
        }

        private void ชอวชาToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_4_2 f = new FormSave_4_2();
            f.Show();
        }

        private void รหสประจำตวToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_4_3 f = new FormSave_4_3();
            f.Show();
        }

        private void ชอนกเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_4_4 f = new FormSave_4_4();
            f.Show();
        }

        private void หองเรยนToolStripMenuItem_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSave_4_5 f = new FormSave_4_5();
            f.Show();
        }

        private void toolStripMenuItem38_Click(object sender, EventArgs e)
        {
            this.Hide();
            FormSystem f = new FormSystem();
            f.Show();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(this.User_ID.Text))
            {
                MessageBox.Show("Please input (เลขประจำตัวครู)");
                this.User_ID.Focus();
                return;
            }

            if (string.IsNullOrEmpty(this.Pin_ID.Text))
            {
                MessageBox.Show("Please input (เลขประจำตัวประชาชน)");
                this.Pin_ID.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Prefix.Text))
            {
                MessageBox.Show("Please input (คำนำหน้า)");
                this.Prefix.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.T_name.Text))
            {
                MessageBox.Show("Please input (ชื่อ)");
                this.T_name.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.T_Lastname.Text))
            {
                MessageBox.Show("Please input (สกุล)");
                this.T_Lastname.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Sex.Text))
            {
                MessageBox.Show("Please input (เพศ)");
                this.Sex.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.dateTimePicker1.Text))
            {
                MessageBox.Show("Please input (วัน/เดือน/ปี เกิด)");
                this.dateTimePicker1.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Age.Text))
            {
                MessageBox.Show("Please input (อายุ)");
                this.Age.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Salary.Text))
            {
                MessageBox.Show("Please input (เงินเดือน)");
                this.Salary.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Position.Text))
            {
                MessageBox.Show("Please input ตำแหน่ง)");
                this.Position.Focus();
                return;
            }


            if (string.IsNullOrEmpty(this.Hous_number.Text))
            {
                MessageBox.Show("Please input (บ้านเลขที่)");
                this.Hous_number.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Moo.Text))
            {
                MessageBox.Show("Please input (หมู่ที่)");
                this.Moo.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Road.Text))
            {
                MessageBox.Show("Please input (ถนน)");
                this.Road.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.District.Text))
            {
                MessageBox.Show("Please input (ตำบล)");
                this.District.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Canton.Text))
            {
                MessageBox.Show("Please input (อำเภอ)");
                this.Canton.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Drorince.Text))
            {
                MessageBox.Show("Please input (จังหวัด)");
                this.Drorince.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.ZIP_code.Text))
            {
                MessageBox.Show("Please input (รหัสไปรษณีย์)");
                this.ZIP_code.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.Phone_nambers.Text))
            {
                MessageBox.Show("Please input (เบอร์โทร)");
                this.Phone_nambers.Focus();
                return;
            }
            if (string.IsNullOrEmpty(this.E_mail.Text))
            {
                MessageBox.Show("Please input (E-mail)");
                this.E_mail.Focus();
                return;
            }

            String strConnString, strSQL;
            strConnString = "Server=localhost;User Id=root; Password=123123; Database=db_project; Pooling=false;Allow Zero Datetime=false;";
            objConn = new MySqlConnection(strConnString);
            objConn.Open();

            strSQL = "INSERT INTO teachers(User_ID,Pin_ID,Prefix,T_name,T_Lastname,Sex,Brithday,Age,Salary,Position,Hous_number,Moo,District,Canton,Drorince,ZIP_code,Phone_nambers,E_mail,Road)" + " VALUES ('" + this.User_ID.Text + "','" + this.Pin_ID.Text + "','" + this.Prefix.Text + "','" + this.T_name.Text + "','" + this.T_Lastname.Text + "','" + this.Sex.Text + "','" + this.Age.Text + "','" + this.dateTimePicker1.Text + "','" + this.Salary.Text + "','" + this.Position.Text + "','" + this.Hous_number.Text + "','" + this.Moo.Text + "','" + this.District.Text + "','" + this.Canton.Text + "','" + this.Drorince.Text + "','" + this.ZIP_code.Text + "','" + this.Phone_nambers.Text + "','" + this.E_mail.Text + "','" + this.Road.Text + "')";
            objCmd = new MySqlCommand(strSQL, objConn);
            objCmd.ExecuteReader();
            MessageBox.Show("Save Successfully.");
           
        }

       

        private void FormSave_1_3_Load(object sender, EventArgs e)
        {	

    

        }

        

     

       

       
    }
}