ما هي حل المشكلة التالية ........

private void butAdd_Click(object sender, EventArgs e)
{
DA.InsertCommand = new SqlCommand("Insert Into [Sales Tree] Values(@Cate_Number, @Design, @Cate_Name, @Quantity, @Price, @Notes)", ConnectionString);
DA.InsertCommand.Parameters.Add("@Cate_Number", SqlDbType.Int).Value = Convert.ToInt32(txtboxCateNumber.Text);
DA.InsertCommand.Parameters.Add("@Design", SqlDbType.NVarChar).Value = txtboxDesing.Text;
DA.InsertCommand.Parameters.Add("@Cate_Name", SqlDbType.NVarChar).Value = txtboxCateName.Text;
DA.InsertCommand.Parameters.Add("@Quantity", SqlDbType.Int).Value =Convert.ToInt32( txtboxQuantity.Text);
DA.InsertCommand.Parameters.Add("@Price", SqlDbType.Int).Value =Convert.ToInt32( txtboxPrice.Text);
DA.InsertCommand.Parameters.Add("@Notes", SqlDbType.NVarChar).Value = txtboxNotes.Text;
ConnectionString.Open();
DA.InsertCommand.ExecuteNonQuery();
ConnectionString.Close();
MessageBox.Show("تمت إضافة الصنف","إضافة صنف");
}