如何同时获取行和行计数
本文关键字:获取 何同时 | 更新日期: 2023-09-27 18:33:04
我有一个同时返回rows
和count
的存储过程。
我尝试按照ADO.net
代码进行操作,但我在项目计数上遇到异常IndexOutOfRange
(项目计数包含count
行)
public List<Product> GetProductDetails(Product p)
{
List<Product> products = new List<Product>();
using (SqlConnection con = new SqlConnection(_connectionString))
{
SqlCommand cmd = new SqlCommand("[usp_Get_ServerPagedProducts]", con);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.AddWithValue("@rvcName", System.Data.SqlDbType.VarChar).Value = p.Name;
cmd.Parameters.AddWithValue("@rvcCode", System.Data.SqlDbType.VarChar).Value = p.Code;
cmd.Parameters.AddWithValue("@riProductTypeID", System.Data.SqlDbType.Int).Value = p.ProductTypeID;
cmd.Parameters.AddWithValue("@ristartIndex", System.Data.SqlDbType.Int).Value = p.RowIndex;
cmd.Parameters.AddWithValue("@rimaxRows", System.Data.SqlDbType.Int).Value = p.PageSize;
con.Open();
using (SqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
Product product = new Product(reader["Name"].ToString(), reader["Code"].ToString(), reader["Description"].ToString(), (DateTime)reader["DateCreated"], Convert.ToInt32(reader["ProductID"]), Convert.ToInt32(reader["ProductTypeID"]), reader["ProductTypeName"].ToString(), Convert.ToInt32(reader["ItemCount"]));
products.Add(product);
}
}
}
return products;
}
存储过程:
SELECT ProductID,
Name,
[Description],
Code,
DateCreated,
ProductTypeID,
ProductTypeName
FROM (
SELECT P.pkProductID AS ProductID,
P.Name AS Name,
P.[Description] AS [Description],
P.Code AS Code,
P.DateCreated AS DateCreated,
P.fkProductTypeID AS ProductTypeID,
PT.Name AS ProductTypeName,
ROW_NUMBER() OVER (ORDER BY P.pkProductID) AS RowNumber
FROM Product P
INNER JOIN ProductType PT ON PT.pkProductTypeID = P.fkProductTypeID
WHERE P.Name LIKE '%' + @rvcName + '%'
AND P.Code LIKE '%' + @rvcCode + '%'
AND (@riProductTypeID = 0 OR P.fkProductTypeID = @riProductTypeID)
) AS tblProduct
WHERE RowNumber >= @ristartIndex
AND RowNumber < (@ristartIndex + @rimaxRows)
SELECT COUNT(*) AS ItemCount
FROM (
SELECT P.pkProductID,
P.Name,
P.[Description],
P.Code,
P.DateCreated,
P.fkProductTypeID AS 'ProductTypeID',
PT.Name AS 'ProductTypeName',
ROW_NUMBER() OVER (ORDER BY P.Name DESC) AS RowNumber
FROM Product P
INNER JOIN ProductType PT ON PT.pkProductTypeID = P.fkProductTypeID
WHERE P.Name LIKE '%' + @rvcName + '%'
AND P.Code LIKE '%' + @rvcCode + '%'
AND (@riProductTypeID = 0 OR P.fkProductTypeID = @riProductTypeID)
) AS TotalCount
是因为它返回两个表吗?解决方案是什么?
如果返回多个记录集,则必须使用NextResult
:
using (SqlDataReader reader = cmd.ExecuteReader())
{
while (reader.Read())
{
Product product = new Product();
product.Name = reader["Name"].ToString();
product.Code = reader["Code"].ToString();
// ...
products.Add(product);
}
if (reader.NextResult() && reader.Read())
{
int itemCount = reader.GetInt32(reader.GetOrdinal("ItemCount"));
foreach(Product p in products)
p.ItemCount = itemCount;
}
}
但在我看来,最好在第一个查询中包含总数。然后它更简单,你不需要最后的循环。数据库可以处理此类子查询。优化器将确保它只执行一次,如果它不是相关的子查询。
检查存储过程返回的列名。它可能是拼写错误或"ItemCount"以外的其他内容。
根据 SqlDataReader.Item 属性的文档,如果未找到具有指定名称的列,则会引发 IndexOutOfRange 异常。