EF下泛型分页方法,更新方法

时间:2023-12-22 10:47:20
/// <summary>
/// 获取分页的分页集合
/// </summary>
/// <typeparam name="S">实体类型</typeparam>
/// <param name="filter">过滤,条件</param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">每页记录数</param>
/// <param name="orderByExpression">排序</param>
/// <param name="ascending">是否排序</param>
/// <returns>返回分页的分页集合</returns>
public PagedResult<T> GetFilteredPageResult<S, T>(Expression<Func<T, bool>> filter, int pageIndex, int pageSize, Expression<Func<T, S>> orderByExpression, bool ascending) where T : class
{
int count = this.DataContext.Set<T>().Where(filter).Count();
return new PagedResult<T>(
pageIndex,
pageSize,
count,
this.GetFilteredElements<S,T>(filter, pageIndex, pageSize, orderByExpression, ascending));
}
/// <summary>
/// 获取有条件的分页对象集合
/// </summary>
/// <typeparam name="S">实体类型</typeparam>
/// <param name="filter">条件过滤</param>
/// <param name="pageIndex">当前页</param>
/// <param name="pageSize">每页记录数</param>
/// <param name="orderByExpression">排序,排序Func表达式</param>
/// <param name="ascending">是否排序</param>
/// <returns>返回有条件的分页对象集合</returns>
public IEnumerable<T> GetFilteredElements<S, T>(Expression<Func<T, bool>> filter, int pageIndex, int pageSize, Expression<Func<T, S>> orderByExpression, bool ascending) where T : class
{
if (filter == (Expression<Func<T, bool>>)null)
{
throw new ArgumentNullException("filter", Messages.exception_FilterCannotBeNull);
} if (pageIndex < )
{
throw new ArgumentException(Messages.exception_InvalidPageIndex);
} if (pageSize <= )
{
throw new ArgumentException(Messages.exception_InvalidPageSize);
} if (orderByExpression == (Expression<Func<T, S>>)null)
{
throw new ArgumentNullException("orderByExpression", Messages.exception_OrderByExpressionCannotBeNull);
} return ascending
?
this.DataContext.Set<T>()
.Where(filter)
.OrderBy(orderByExpression)
.Skip((pageIndex - ) * pageSize)
.Take(pageSize)
.ToList()
:
this.DataContext.Set<T>()
.Where(filter)
.OrderByDescending(orderByExpression)
.Skip((pageIndex - ) * pageSize)
.Take(pageSize)
.ToList();
} /// <summary>
/// 获取记录数
/// </summary>
/// <param name="filter">条件filter</param>
/// <returns>返回记录数</returns>
public int GetRecordCount<T>(Expression<Func<T, bool>> filter) where T : class
{
return this.DataContext.Set<T>().Where(filter).Count();
}
public class PagedResult<TEntity>
{
/// <summary>
/// 数据列表
/// </summary>
public IEnumerable<TEntity> List { get; private set; } /// <summary>
/// 每页记录数
/// </summary>
public int PageSize { get; private set; } /// <summary>
/// 页索引
/// </summary>
public int PageIndex { get; private set; } /// <summary>
/// 总记录数
/// </summary>
public int RecordCount { get; private set; } /// <summary>
/// 总页数
/// </summary>
public int TotalPages
{
get
{
int pages = ;
if (RecordCount > && PageSize > )
{ int temp = RecordCount % PageSize;
pages = RecordCount / PageSize;
if (temp > )
{
return pages + ;
}
} return pages;
}
} /// <summary>
/// Constructor
/// </summary>
/// <param name="pageIndex">页索引</param>
/// <param name="pageSize">每页记录数</param>
/// <param name="recordCount">总记录数</param>
/// <param name="list">数据列表</param>
public PagedResult(int pageIndex, int pageSize, int recordCount, IEnumerable<TEntity> list)
{
this.List = list;
this.PageIndex = pageIndex;
this.PageSize = pageSize;
this.RecordCount = recordCount;
}
}

/// <summary>
/// 通过条件批量更新实体的部分值【异步更新】
/// </summary>
/// <param name="filterExpression">更新条件</param>
/// <param name="updateExpression">更新值</param>
public virtual void UpdateAsync<T>(Expression<Func<T, bool>> filterExpression, Expression<Func<T, T>> updateExpression) where T : class
{
DataContext.Set<T>().Where(filterExpression).UpdateAsync(updateExpression);
}

EF迁移:

PM> Enable-Migrations -EnableAutomaticMigrations
PM> Add-Migration InitialCreate
PM> Update-Database -Verbose