/// <summary>
 /// Check if years is not empty
 /// Assign skill to vacancy
 /// catch format and constraint errors
 /// </summary>
 private void btnAssignSkill_Click(object sender, EventArgs e)
 {
     try
     {
         if (txtYears.Text != "")
         {
             DataRow newVacancySkill = DM.dtVacancySkill.NewRow();
             newVacancySkill["VacancyID"] = dgvVacancy["VacancyID", cmVacancy.Position].Value;
             newVacancySkill["SkillID"]   = dgvSkill["SkillID", cmSkill.Position].Value;
             newVacancySkill["Years"]     = Convert.ToInt32(txtYears.Text);
             DM.dsLookingGlass.Tables["VacancySkill"].Rows.Add(newVacancySkill);
             DM.UpdateVacancySkill();
             MessageBox.Show("Skill assigned successfully");
         }
         else
         {
             MessageBox.Show("Please enter a number in years.", "Error");
         }
     }
     catch (ConstraintException)
     {
         MessageBox.Show("This skill has already been assigned to this vacancy.", "Error");
     }
     catch (FormatException)
     {
         MessageBox.Show("Please enter a number in years.", "Error");
     }
 }
        /// <summary>
        /// Check if vacancy is in application
        /// If not prompt user to confirm deleteion, if yes, delete vacancy and all skill asign to it
        /// </summary>
        private void btnDeleteVacancy_Click(object sender, EventArgs e)
        {
            DataRow deleteVacancyRow = DM.dtVacancy.Rows[currencyManager.Position];
            int     lookForVacancyID = Convert.ToInt32(txtVacancyID.Text);
            int     vacancy          = 0;//Count amount of vacancy id in application table
            int     row = 0;

            foreach (DataRow drApplication in DM.dtApplication.Rows)
            {
                int VacancyID = Convert.ToInt32(drApplication["VacancyID"].ToString());
                if (VacancyID == (lookForVacancyID))
                {
                    vacancy++;
                }
            }
            if (vacancy == 0)
            {
                if (MessageBox.Show("Do you want to delete this vacancy? Once deleted it will disappear from the database permanently.", "Delete Vacancy", MessageBoxButtons.YesNo) == DialogResult.Yes)
                {
                    foreach (DataRow drSkill in DM.dtVacancySkill.Rows)
                    {
                        int VacancyID = Convert.ToInt32(drSkill["VacancyID"].ToString());
                        if (VacancyID == (lookForVacancyID))
                        {
                            try
                            {
                                DataRow deleteVacancySkillRow = DM.dtVacancySkill.Rows[row];
                                deleteVacancySkillRow.Delete();
                            }
                            catch
                            {
                                MessageBox.Show("Something went wrong when trying to delete skill.");
                            }
                        }
                        row++;
                    }
                    DM.UpdateVacancySkill();

                    try
                    {
                        deleteVacancyRow.Delete();
                        DM.UpdateVacancy();
                        MessageBox.Show("Vacancy deleted successfully");
                    }
                    catch
                    {
                        MessageBox.Show("Error occured while deleting Vacancy");
                    }
                }
            }
            else
            {
                MessageBox.Show("You may only delete a vacancy that has no applications");
            }
        }