private void ViewData()
 {
     if (dataGridView1.CurrentRow != null)
     {
         int KhachhangID;
         int.TryParse(dataGridView1.CurrentRow.Cells[0].Value.ToString(), out KhachhangID);
         Models.Khachhang kh = lstKhachhang.Find(x => x.KhachhangID == KhachhangID);
         if (KhachhangID > 0)
         {
             textBox2.Text        = kh.Tenkhachhang;
             dateTimePicker1.Text = kh.Ngaysinh.ToShortDateString();
             radioButton1.Checked = false;
             radioButton2.Checked = false;
             if (kh.Gioitinh)
             {
                 radioButton1.Checked = true;
             }
             else
             {
                 radioButton2.Checked = true;
             }
             maskedTextBox1.Text = kh.Sodienthoai;
             textBox6.Text       = kh.Diachi;
             textBox7.Text       = kh.KhachhangID.ToString();
             button2.Enabled     = false;
             button3.Enabled     = true;
             button4.Enabled     = true;
         }
     }
 }
 private Models.Khachhang GetData()
 {
     Models.Khachhang kh = new Models.Khachhang();
     kh.Tenkhachhang = textBox2.Text;
     kh.Ngaysinh     = DateTime.Parse(dateTimePicker1.Text);
     kh.Sodienthoai  = maskedTextBox1.Text;
     kh.Diachi       = textBox6.Text;
     if (textBox7.Text != "")
     {
         kh.KhachhangID = int.Parse(textBox7.Text);
     }
     if (radioButton1.Checked == true)
     {
         kh.Gioitinh = true;
     }
     else
     {
         kh.Gioitinh = false;
     }
     return(kh);
 }
 private Models.Khachhang GetData()
 {
     Models.Khachhang kh = new Models.Khachhang();
     kh.Tenkhachhang = textBox2.Text;
     kh.Ngaysinh = DateTime.Parse(dateTimePicker1.Text);
     kh.Sodienthoai = maskedTextBox1.Text;
     kh.Diachi = textBox6.Text;
     if (textBox7.Text != "")
     {
         kh.KhachhangID = int.Parse(textBox7.Text);
     }
     if (radioButton1.Checked==true)
     {
         kh.Gioitinh = true;
     }
     else { kh.Gioitinh = false; }
     return kh;
 }