asp.net在sql中獲取特定值

Question

在我的SQL數據庫中

 ID Name Cost Weight
 1 John  15   36
 2 Mike  8    45
 3 Smith 10   12

我有一個下拉列表

<asp:SqlDataSource ID="MainCost" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" SelectCommand="SELECT DISTINCT [Name] FROM [Human]"></asp:SqlDataSource>

包含名稱的值和一個按鈕，單擊該按鈕應將Cost * Weight乘以，我將如何獲得要乘以的特定值？ 我也有一個DbConnctivity的課程，謝謝

Answer 1

我寫了一個function用於獲取Cost*Weight的價值selected user從DropdownList 。 您可以在從DropDownList選擇用戶並Clicked Button時調用該函數

注意：請根據需要更改ConnectionString和UIControl名稱

完整的代碼：

protected void Button1_Click(object sender, EventArgs e)
        {            
       int TotalCostWeight=getTotalWeightandCost();    
        }

     private   int getTotalWeightandCost()
        {
            int total = 0;
            String strCon = "Data Source=systemname;Initial Catalog=databasename;uid=uid;pwd=pwd;Integrated Security=True;";
            using (SqlConnection sqlCon = new SqlConnection(strCon))
            {
                String strCmd = "SELECT Cost*Weight as total FROM [Human] WHERE [Name] = @Name";
                using(SqlCommand sqlcommand = new SqlCommand(strCmd, sqlCon))
                sqlCon.Open();
                command.Parameters.Add("@Name", SqlDbType.VarChar).Value = DropDownList1.SelectedValue.ToString();
                SqlDataReader sReader = sqlcommand.ExecuteReader();
                if (sReader.Read())
                    total = Convert.ToInt32(sReader[0].ToString());
            }
        }
            return total;
        }

Answer 2

SELECT Cost* Weight FROM [Human] WHERE [Name] = @Name

（放置字符串而不是@Name或使用SQL參數）

SQL參數示例：

command.Parameters.Add("@Name", SqlDbType.VarChar).Value = "Jhon";