ผมสามารถโชว์ภาพที่อยู่ตาราง ของฐานข้อมูลได้แล้วครับ เลยเอา โค๊ดมาฝาก แต่ติดที่ เมื่อเจอตารางถาพที่เป็น Null ทำไม่มัน Err

if (drSQL.Read())
{
     Try
     {
            string chkType = "";
            txtID.Text = drSQL["IDTeacher"].ToString();
            txtPer.Text = drSQL["PreName"].ToString();
            txtFName.Text = drSQL["NameFirst"].ToString();
            txtLName.Text = drSQL["NameLast"].ToString();
            chkType = drSQL["Sex"].ToString();
            if (chkType == "1")
            {
                rdoMane.Checked = true;
            }
            else
            {
                rdoFamale.Checked = true;
            }
            txtPLevel.Text = drSQL["Office"].ToString();
            txtClassRoom.Text = drSQL["TPosition"].ToString();
            txtGroup.Text = drSQL["PositionNew"].ToString();

           
            Byte[] byteBLOBData = new Byte[0];
            byteBLOBData = (Byte[])drSQL["PicPresent"];
            MemoryStream stmBLOBData = new MemoryStream(byteBLOBData);
            if (stmBLOBData != null)
            {
              pictureBox1.Image = Image.FromStream(stmBLOBData, false, true);                           
            }
            else
            {
                MessageBox.Show("ไม่มีภาพ", "ข้อผิดผลาด");
                pictureBox1.Image = null;                           
            }
     }
     catch (Exception e)
     {
                MessageBox.Show(e.Message, "SQL Error");
     }
}

private void TextShowData()
        {
            SqlConnection cnSQL;

            SqlCommand cmSQL;

            SqlDataReader drSQL;

            string strSQL;

           

            if (rdbStudunts.Checked == true)
            {
                try
                {
                   

                    strSQL = "SELECT IDStudent, PreName, NameFirst" +
                           ", NameLast, Sex, Status, PLevel, PClass, PRoom " +
                           " FROM TBStudent " +
                           " WHERE (Status = 1) AND (IDStudent=" + textBox1.Text +")";
                    
                    cnSQL = new SqlConnection(Conn);
                    cnSQL.Open();
                    cmSQL = new SqlCommand(strSQL, cnSQL);
                    drSQL = cmSQL.ExecuteReader();

                    if (drSQL.Read())
                    {
                        string chkType = "";
                        txtID.Text = drSQL["IDStudent"].ToString();
                        txtPer.Text = drSQL["PreName"].ToString();
                        txtFName.Text = drSQL["NameFirst"].ToString();
                        txtLName.Text = drSQL["NameLast"].ToString();
                        chkType = drSQL["Sex"].ToString();
                        if (chkType == "1")
                        {
                            rdoMane.Checked = true;
                        }
                        else
                        {
                            rdoFamale.Checked = true;
                        }
                        txtPLevel.Text = drSQL["PLevel"].ToString();
                        txtClassRoom.Text = drSQL["PClass"].ToString() + "/" + drSQL["PRoom"].ToString();
                    }
                    drSQL.Close();
                    cnSQL.Close();
                    cmSQL.Dispose();
                    cnSQL.Dispose();
                }
                catch (SqlException e)
                {
                    MessageBox.Show(e.Message, "SQL Error/ข้อผิดผลาดคำสั่ง SQL");
                }
                catch (Exception e)
                {
                    MessageBox.Show(e.Message, "General Error/ข้อผิดผลาดอื่น ๆ");
                }
            }
            else if(rdbHumman.Checked==true)
            {
                try  //Try 2
                {
                   //เลือกจากตารางบุคคลากร

                    strSQL = "SELECT IDTeacher, PreName, NameFirst" +
                             ", NameLast, Status, Sex, TPosition, Office, PositionNew, PicPresent" +
                             " FROM TTeacher" +
                             " WHERE (Status = 1) AND (IDTeacher ="+ textBox1.Text +")";
                    
                    cnSQL = new SqlConnection(Conn);
                    cnSQL.Open();
                    cmSQL = new SqlCommand(strSQL, cnSQL);
                    drSQL = cmSQL.ExecuteReader();

                    
                        if (drSQL.Read())
                        {
                            string chkType = "";
                            txtID.Text = drSQL["IDTeacher"].ToString();
                            txtPer.Text = drSQL["PreName"].ToString();
                            txtFName.Text = drSQL["NameFirst"].ToString();
                            txtLName.Text = drSQL["NameLast"].ToString();
                            chkType = drSQL["Sex"].ToString();
                            if (chkType == "1")
                            {
                                rdoMane.Checked = true;
                            }
                            else
                            {
                                rdoFamale.Checked = true;
                            }
                            txtPLevel.Text = drSQL["Office"].ToString();
                            txtClassRoom.Text = drSQL["TPosition"].ToString();
                            txtGroup.Text = drSQL["PositionNew"].ToString();

                            if (drSQL["PicPresent"] == System.DBNull.Value)
                            {
                                pictureBox1.Image = null;
                            }
                            else
                            {
                                Byte[] byteBLOBData = new Byte[0];

                                byteBLOBData = (Byte[])drSQL["PicPresent"];

                                MemoryStream stmBLOBData = new MemoryStream(byteBLOBData);
                                this.pictureBox1.Image = Image.FromStream(stmBLOBData, false, false);
                            }
                                

                        


                        
                    
                    }
                    drSQL.Close();
                    cnSQL.Close();
                    cmSQL.Dispose();
                    cnSQL.Dispose();
                } //จบ Try 2
                catch (SqlException e)
                {
                    MessageBox.Show(e.Message, "SQL Error/ข้อผิดผลาดคำสั่ง SQL");
                }
                catch (Exception e)
                {
                    MessageBox.Show(e.Message, "General Error/ข้อผิดผลาดอื่น ๆ");
                }


            }//end else if
        }