Question

我在将参数传递给SqlCommand的SQL字符串时遇到问题。当我使用选项1（见下文）时，代码可以正常工作。当我使用选项2时，它不起作用。我不确定如何使.AddWithValue方法使用SqlCommand。

任何帮助将不胜感激！

private string [] GetOrderInfo (string folder)
{
    string [] order = new string [] { "date", "order#", "storeid", "storename", "username" };

    using (SqlConnection conn = new SqlConnection (_connectionString))
    {
        conn.Open ();

        // Option 1: this line works.
        //string sql = "select * from OrderProduct where OrderProductID=26846";

        // Option 2: this line doesn't work.
        string sql = "select * from OrderProduct where OrderProductID=@folder;";

        using (SqlCommand command = new SqlCommand (sql, conn))
        {
            command.Parameters.AddWithValue ("@folder", folder);

            using (SqlDataReader reader = command.ExecuteReader ())
            {
                while (reader.Read ())
                    order [1] = Convert.ToString (reader.GetInt32 (1));
            }
        }

        conn.Close ();
    } // using (SqlConnection conn = new SqlConnection (connectionString))

    return order;
}

Answer 1

尝试使用

station   date       he  actual forecast   as_of  
KSBN      2/1/2016   4   10.4   15.1       1/31/2016 6:00  
KSBN      2/1/2016   5   12.7   11.32      1/31/2016 6:00

Answer 2

AddWithValue 方法使用值的类型来定义正确的 SqlDbType 。因此，如果您的字段 OrderProductID 是 INT 的类型，则需要添加 int 。

样品：

command.Parameters.AddWithValue ("@folder", 26846);

另一种简单方法是使用简单对象映射器，如SqlDatabaseCommand或Dapper。

using (var cmd = new SqlDatabaseCommand(_connection))
{
    cmd.CommandText.AppendLine(" SELECT * ")
                   .AppendLine("   FROM EMP ")
                   .AppendLine("  WHERE EMPNO = @EmpNo ")
                   .AppendLine("    AND HIREDATE = @HireDate ");

    cmd.Parameters.AddValues(new
            {
                EmpNo = 7369,
                HireDate = new DateTime(1980, 12, 17)
            });

    var emps = cmd.ExecuteTable<Employee>();
}

Answer 3

您可以尝试：

userService.getUsers().then(function(userList) {
    console.log(userList);
})

将参数传递给SqlCommand的问题

3 个答案: