public static IQueryable ToPagedList(this IQueryable source, PageCtl pageCtl)
{
if (pageCtl == null)
{
return(source);
}
if (pageCtl.PageSize == 0)
{
pageCtl.PageSize = 30;
}
if (pageCtl.PageIndex == 0)
{
pageCtl.PageIndex = 1;
}
int total = source.Count();
pageCtl.TotalCount = total;
pageCtl.TotalPages = total / pageCtl.PageSize;
if (total % pageCtl.PageSize > 0)
{
pageCtl.TotalPages++;
}
string OrderByField = pageCtl.OrderByField;
bool Ascending = !pageCtl.Dscending;
Type type = source.ElementType;
if (string.IsNullOrEmpty(OrderByField))
{
PropertyInfo[] propertys = type.GetProperties();
if (propertys.Length == 0)
{
throw new Exception("当前实体未包含属性！");
}
var pIs = from c in propertys where c.GetCustomAttributes(false).Count() > 0 select c;
var pI = from c in pIs where c.CustomAttributes.Where(w => w.AttributeType == typeof(System.ComponentModel.DataAnnotations.KeyAttribute)).Count() > 0 select c;
if (pI.Count() > 0)
{
OrderByField = pI.First().Name;
}
else
{
OrderByField = propertys[0].Name;
}
}
PropertyInfo property = type.GetProperty(OrderByField);
if (property == null)
{
throw new Exception("错误：\r\n当前实体中不存在指定的排序字段：" + OrderByField);
}
ParameterExpression param = Expression.Parameter(type, "p");
Expression propertyAccessExpression = Expression.MakeMemberAccess(param, property);
LambdaExpression orderByExpression = Expression.Lambda(propertyAccessExpression, param);
string methodName = Ascending ? "OrderBy" : "OrderByDescending";
MethodCallExpression resultExp = Expression.Call(
typeof(Queryable), methodName, new Type[] { type, property.PropertyType },
source.Expression,
Expression.Quote(orderByExpression)
);
var query = source.Provider.CreateQuery(resultExp);
var PageSize = pageCtl.PageSize;
if (pageCtl.PageIndex > pageCtl.TotalPages)
{
pageCtl.PageIndex = pageCtl.TotalPages;
}
if (pageCtl.PageIndex < 1)
{
pageCtl.PageIndex = 1;
}
// this.PageIndex = pageCtl.PageIndex;
//pageCtl.TotalPages = this.TotalPages;
//pageCtl.TotalCount = this.TotalCount;
query = query._Skip((pageCtl.PageIndex - 1) * pageCtl.PageSize)._Take(pageCtl.PageSize);
return(query);
}
public PagedList(IQueryable <T> source, PageCtl pageCtl)
{
if (pageCtl == null)
{
this.AddRange(source.ToList());
this.ToList();
return;
}
if (pageCtl.PageSize == 0)
{
pageCtl.PageSize = 30;
}
if (pageCtl.PageIndex == 0)
{
pageCtl.PageIndex = 1;
}
int total = source.Count();
this.TotalCount = total;
this.TotalPages = total / pageCtl.PageSize;
if (total % pageCtl.PageSize > 0)
{
TotalPages++;
}
string OrderByField = pageCtl.OrderByField;
bool Ascending = !pageCtl.Dscending;
Type type = typeof(T);
if (string.IsNullOrEmpty(OrderByField))
{
PropertyInfo[] propertys = type.GetProperties();
if (propertys.Length == 0)
{
throw new Exception("当前实体未包含属性！");
}
//OrderByField = propertys[0].Name;
foreach (var item in propertys.Where(x => x.GetCustomAttributes(false).Count() > 0))
{
if (item.CustomAttributes.Where(x => x.AttributeType == new System.ComponentModel.DataAnnotations.KeyAttribute().GetType()).FirstOrDefault() != null)
{
OrderByField = item.Name;
break;
}
}
}
PropertyInfo property = type.GetProperty(OrderByField);
if (property == null)
{
throw new Exception("错误：\r\n当前实体中不存在指定的排序字段：" + OrderByField);
}
ParameterExpression param = Expression.Parameter(type, "p");
Expression propertyAccessExpression = Expression.MakeMemberAccess(param, property);
LambdaExpression orderByExpression = Expression.Lambda(propertyAccessExpression, param);
string methodName = Ascending ? "OrderBy" : "OrderByDescending";
MethodCallExpression resultExp = Expression.Call(
typeof(Queryable), methodName, new Type[] { type, property.PropertyType },
source.Expression,
Expression.Quote(orderByExpression)
);
var query = source.Provider.CreateQuery <T>(resultExp);
this.PageSize = pageCtl.PageSize;
if (pageCtl.PageIndex > this.TotalPages)
{
pageCtl.PageIndex = this.TotalPages;
}
if (pageCtl.PageIndex < 1)
{
pageCtl.PageIndex = 1;
}
this.PageIndex = pageCtl.PageIndex;
pageCtl.TotalPages = this.TotalPages;
pageCtl.TotalCount = this.TotalCount;
var list = query.Skip((pageCtl.PageIndex - 1) * pageCtl.PageSize).Take(pageCtl.PageSize).ToList();
this.AddRange(list);
this.ToList();
}
public static List <T> ToPagedList <T>(this IEnumerable <T> linq, PageCtl pcl)
{
return(new PagedList <T>(linq, pcl).ToList());
}
