public MyQueryable <T> OrderBy <TProperty>(Expression <Func <T, TProperty> > expression,
MyDbOrderBy orderBy = MyDbOrderBy.Asc)
{
if (expression.Body.NodeType == ExpressionType.MemberAccess)
{
_orderBy = GetOrderByString((MemberExpression)expression.Body);
if (orderBy == MyDbOrderBy.Desc)
{
_orderBy += " DESC";
}
}
return(this);
}
public async Task <List <T> > FetchAsync <T>(Expression <Func <T, bool> > where = null, Expression <Func <T, object> > orderBy = null,
MyDbOrderBy dbSort = MyDbOrderBy.Asc) where T : class, new()
{
var query = new MyQueryable <T>(_connectionString);
if (where != null)
{
query.Where(where);
}
if (orderBy != null)
{
query.OrderBy(orderBy, dbSort);
}
return(await query.ToListAsync());
}
public MyQueryable <T> ThenOrderBy <TProperty>(Expression <Func <T, TProperty> > expression,
MyDbOrderBy orderBy = MyDbOrderBy.Asc)
{
if (string.IsNullOrWhiteSpace(_orderBy))
{
throw new ArgumentNullException(nameof(_orderBy), "排序字段为空，必须先调用OrderBy或OrderByDesc才能调用此方法");
}
if (expression.Body.NodeType == ExpressionType.MemberAccess)
{
_orderBy += "," + GetOrderByString((MemberExpression)expression.Body);
if (orderBy == MyDbOrderBy.Desc)
{
_orderBy += " DESC";
}
}
return(this);
}
/// <summary>
/// 根据条件加载一个实体
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="where">查询条件</param>
/// <param name="orderBy">排序字段</param>
/// <param name="dbSort">正序或倒序</param>
/// <returns>实体，若记录为空，返回default(T)</returns>
public T Load <T>(Expression <Func <T, bool> > where = null,
Expression <Func <T, object> > orderBy = null,
MyDbOrderBy dbSort = MyDbOrderBy.Asc) where T : class, new()
{
var query = new MyQueryable <T>(_connectionString);
if (where != null)
{
query.Where(where);
}
if (orderBy != null)
{
query.OrderBy(orderBy, dbSort);
}
return(query.FirstOrDefault());
}
public async Task <PagingResult <T> > PageListAsync <T>(int pageIndex,
int pageSize,
Expression <Func <T, bool> > where = null,
Expression <Func <T, object> > orderBy = null,
MyDbOrderBy dbSort = MyDbOrderBy.Asc) where T : class, new()
{
var query = new MyQueryable <T>(_connectionString);
if (where != null)
{
query.Where(where);
}
if (orderBy != null)
{
query.OrderBy(orderBy, dbSort);
}
return(await query.ToPageListAsync(pageIndex, pageSize));
}
/// <summary>
/// 加载分页列表
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="pageIndex">当前页码</param>
/// <param name="pageSize">每页条数</param>
/// <param name="recordCount">记录总数</param>
/// <param name="where">查询条件</param>
/// <param name="orderBy">排序字段</param>
/// <param name="dbSort">正序或倒序</param>
/// <returns>实体列表，输出记录总数</returns>
public List <T> PageList <T>(int pageIndex,
int pageSize,
out int recordCount,
Expression <Func <T, bool> > where = null,
Expression <Func <T, object> > orderBy = null,
MyDbOrderBy dbSort = MyDbOrderBy.Asc) where T : class, new()
{
var query = new MyQueryable <T>(_connectionString);
if (where != null)
{
query.Where(where);
}
if (orderBy != null)
{
query.OrderBy(orderBy, dbSort);
}
return(query.ToPageList(pageIndex, pageSize, out recordCount));
}