private void TXT_PRICE_KeyDown(object sender, KeyEventArgs e)
 {
     if(e.KeyCode==Keys.Enter&&TXT_PRICE.Text!=string.Empty)
     {
         TXT_QUA.Focus();
     }
 }
 void CLEAR_TXTS()
 {
      TXT_ID_PRODUCT.Clear();
      TXT_NAME_PRODUCT.Clear();
      TXT_PRICE.Clear();
      TXT_QUA.Clear() ;
      TXT_AMOUNT.Clear();
      TXT_DISCOUNT.Clear();
      TXT_TO_AMOUNT.Clear();
 }
        private void button1_Click(object sender, EventArgs e)
        {
            CLEAR_TXTS();   
            FRM_PRODUCT_LIST PRD = new FRM_PRODUCT_LIST();

            PRD.ShowDialog();
            this.TXT_ID_PRODUCT.Text = PRD.DGV_PRODUCTS.CurrentRow.Cells[0].Value.ToString();
            this.TXT_NAME_PRODUCT.Text = PRD.DGV_PRODUCTS.CurrentRow.Cells[1].Value.ToString();
            this.TXT_PRICE.Text = PRD.DGV_PRODUCTS.CurrentRow.Cells[3].Value.ToString();
            TXT_QUA.Focus();

        }
 private void dataGridView1_DoubleClick(object sender, EventArgs e)
 {
     try
     {
         TXT_ID_PRODUCT.Text = this.dataGridView1.CurrentRow.Cells[0].Value.ToString();
         TXT_NAME_PRODUCT.Text = this.dataGridView1.CurrentRow.Cells[1].Value.ToString();
         TXT_PRICE.Text = this.dataGridView1.CurrentRow.Cells[2].Value.ToString();
         TXT_QUA.Text = this.dataGridView1.CurrentRow.Cells[3].Value.ToString();
         TXT_AMOUNT.Text = this.dataGridView1.CurrentRow.Cells[4].Value.ToString();
         TXT_DISCOUNT.Text = this.dataGridView1.CurrentRow.Cells[5].Value.ToString();
         TXT_TO_AMOUNT.Text = this.dataGridView1.CurrentRow.Cells[6].Value.ToString();
         dataGridView1.Rows.RemoveAt(dataGridView1.CurrentRow.Index);
         TXT_QUA.Focus();
     }
     catch
     {
         return;
     }
 }