[转]MVC 分页

本内容代码段抄自传智视频

/// <summary>
/// 数据库分页
/// </summary>
static List<dynamic> GetPageList<T, TKey>(Expression<Func<T, dynamic>> select, Expression<Func<T, bool>> whereLambda, Expression<Func<T, TKey>> orderLambda, int pageSize, int pageIndex, out int total, bool isAsc)
    where T : class
{
    StudyDBEntities context = new StudyDBEntities();
    total = context.Set<T>().Where(whereLambda).Count();
    var result = context.Set<T>().Where(whereLambda);
    if (isAsc)
        result = result.OrderBy(orderLambda);
    else
        result = result.OrderByDescending(orderLambda);
    return result.Skip(pageSize * (pageIndex - 1)).Take(pageSize).Select(select).ToList();
}

其中 total 返回符合条件的总行数

result 返回符合条件的数据

使用：

int total = 0;
var list = GetPageList<Student, int>(o => o, o => o.ID > 2, o => o.ID, 5, 5, out total, true);

ViewData.Model = 实体
    .OrderBy(u => u.UserId)
    .Skip(pageSize * (pageIndex - 1))
    .Take(pageSize)
    .AsEnumerable();

SQL 生成如下：

SELECT 
    [GroupBy1].[A1] AS [C1]
    FROM ( SELECT 
        COUNT(1) AS [A1]
        FROM [dbo].[Student] AS [Extent1]
        WHERE [Extent1].[ID] > 2
    )  AS [GroupBy1]

SELECT TOP (5) 
[Filter1].[ID] AS [ID], 
[Filter1].[Name] AS [Name], 
[Filter1].[Class] AS [Class]
FROM ( SELECT [Extent1].[ID] AS [ID], [Extent1].[Name] AS [Name], [Extent1].[Class] AS [Class], 
    row_number() OVER (ORDER BY [Extent1].[ID] ASC) AS [row_number]
    FROM [dbo].[Student] AS [Extent1]
    WHERE [Extent1].[ID] > 2
)  AS [Filter1]
WHERE [Filter1].[row_number] > 20
ORDER BY [Filter1].[ID] ASC