为了运行executeScalar
,我在 Internet 上尝试了很多建议,但我得到了错误ExecuteScalar: Connection property has not been initialized
。我的INSERT
查询工作正常,问题出在executeScalar
.
conn.Open();
SqlCommand cmd = new SqlCommand(
"INSERT INTO Products (Product_Name,Product_BarCode,Product_CP,Product_SP,
Product_Countainer,Product_Pcs,Product_MFGDate,
Product_ExpiryDate,Product_Grade)
Values ('" + Name.Text + "','" + BarCode.Text + "','" + CostP.Value + "','" +
SellingP.Value + "','" + Countainer.Value + "','" + Pcs.Value + "','" +
MfgDate.Value + "','" + ExpDate.Value + "','" + Grade.SelectedItem + "')",
conn);
cmd.ExecuteNonQuery();
conn.Close();
conn.Open();
cmd.Connection = conn;
cmd = new SqlCommand("SELECT SUM(Product_CP) FROM Products AS Amount");
Amount = (double)cmd.ExecuteScalar();
MessageBox.Show(Amount.ToString());
conn.Close();