#region IQueryable的扩展方法
#region 根据第三方条件是否为真是否执行指定条件的查询
///
/// 根据第三方条件是否为真是否执行指定条件的查询
///
/// 动态类型
/// 查询的结果
public static IQueryable WhereIf(this IQueryable source, Expression> where,
bool condition)
{
if (PublicHelper.CheckArgument(where, "where"))
{
return condition ? source.Where(where) : source;
}
return null;
}
#endregion
#region 把IQueryable集合按照指定的属性与排序方式进行排序
///
/// 把IQueryable集合按照指定的属性与排序方式进行排序
///
/// 数据集类型
/// 返回排序后的结果集
public static IOrderedQueryable OrderBy(this IQueryable source, string propName,
ListSortDirection listSort = ListSortDirection.Ascending)
{
if (PublicHelper.CheckArgument(propName, "propName"))
{
return QueryableHelper.OrderBy(source, propName, listSort);
}
return null;
}
#endregion
#region 把IQueryable集合按照指定的属性与排序方式进行排序
///
/// 把IQueryable集合按照指定的属性与排序方式进行排序
///
/// 数据集类型
/// 返回排序后的结果集
public static IOrderedQueryable OrderBy(this IQueryable source, PropertySortCondition sortCondition)
{
if (PublicHelper.CheckArgument(sortCondition, "sortCondition"))
{
return source.OrderBy(sortCondition.PropertyName, sortCondition.ListSortDirection);
}
return null;
}
#endregion
#region 把IOrderedQueryable集合按照指定的属性与排序方式进行再排序
///
/// 把IOrderedQueryable集合按照指定的属性与排序方式进行排序
///
/// 数据集类型
/// 返回排序后的结果集
public static IOrderedQueryable ThenBy(this IOrderedQueryable source, string propName,
ListSortDirection listSort = ListSortDirection.Ascending)
{
if (PublicHelper.CheckArgument(propName, "propName"))
{
return QueryableHelper.ThenBy(source, propName, listSort);
}
return null;
}
#endregion
#region 把IOrderedQueryable集合按照指定的属性与排序方式进行再排序
///
/// 把IOrderedQueryable集合按照指定的属性与排序方式进行排序
///
/// 数据集类型
/// 返回排序后的结果集
public static IOrderedQueryable ThenBy(this IOrderedQueryable source, PropertySortCondition sortCondition)
{
if (PublicHelper.CheckArgument(sortCondition, "sortCondition"))
{
return QueryableHelper.ThenBy(source, sortCondition.PropertyName, sortCondition.ListSortDirection);
}
return null;
}
#endregion
#region 多条件排序分页查询
///
/// 把IQueryable集合按照指定的属性与排序方式进行排序后，再按照指定的条件提取指定页码指定条目数据
///
/// 动态类型
/// 子集
public static IQueryable Where(this IQueryable source, Expression> where, int pageIndex,
int pageSize, out int total, params PropertySortCondition[] sortConditions) where T : class, new()
{
IQueryable temp = null;
int i = 0;
if (PublicHelper.CheckArgument(source, "source")
&& PublicHelper.CheckArgument(where, "where")
&& PublicHelper.CheckArgument(pageIndex, "pageIndex")
&& PublicHelper.CheckArgument(pageSize, "pageSize")
&& PublicHelper.CheckArgument(sortConditions, "sortConditions"))
{
//判断是不是首个排序条件
int count = 0;
//得到满足条件的总记录数
i = source.Count(where);
//对数据源进行排序
IOrderedQueryable orderSource = null;
foreach (PropertySortCondition sortCondition in sortConditions)
{
orderSource = count == 0
? source.OrderBy(sortCondition.PropertyName, sortCondition.ListSortDirection)
: orderSource.ThenBy(sortCondition.PropertyName, sortCondition.ListSortDirection);
count++;
}
source = orderSource;
temp = source != null
? source.Where(where).Skip((pageIndex - 1) * pageSize).Skip(pageSize)
: Enumerable.Empty().AsQueryable();
}
total = i;
return temp;
//PublicHelper.CheckArgument(source, "source");
//PublicHelper.CheckArgument(where, "where");
//PublicHelper.CheckArgument(pageIndex, "pageIndex");
//PublicHelper.CheckArgument(pageSize, "pageSize");
//PublicHelper.CheckArgument(sortConditions, "sortConditions");
判断是不是首个排序条件
//int count = 0;
得到满足条件的总记录数
//total = source.Count(where);
对数据源进行排序
//IOrderedQueryable orderSource = null;
//foreach (PropertySortCondition sortCondition in sortConditions)
//{
// orderSource = count == 0
// ? source.OrderBy(sortCondition.PropertyName, sortCondition.ListSortDirection)
// : orderSource.ThenBy(sortCondition.PropertyName, sortCondition.ListSortDirection);
// count++;
//}
//source = orderSource;
//return source != null
// ? source.Where(where).Skip((pageIndex - 1) * pageSize).Skip(pageSize)
// : Enumerable.Empty().AsQueryable();
}
#endregion
#region 多条件排序查询
/
/ 多条件排序查询
/
/ 动态类型
/ 子集
//public static IQueryable Where(this IQueryable source, Expression> where, params PropertySortCondition[] sortConditions) where T : class, new()
//{
// log = LogManager.GetLogger(string.Format("查询表_{0}", typeof(T)));
// IQueryable temp = null;
// Logger("", () =>
// {
// if (PublicHelper.CheckArgument(source, "source")
// && PublicHelper.CheckArgument(where, "where")
// && PublicHelper.CheckArgument(sortConditions, "sortConditions"))
// {
// //判断是不是首个排序条件
// int count = 0;
// //对数据源进行排序
// IOrderedQueryable orderSource = null;
// foreach (PropertySortCondition sortCondition in sortConditions)
// {
// orderSource = count == 0
// ? source.OrderBy(sortCondition.PropertyName, sortCondition.ListSortDirection)
// : orderSource.ThenBy(sortCondition.PropertyName, sortCondition.ListSortDirection);
// count++;
// }
// source = orderSource;
// temp = source != null
// ? source.Where(where)
// : Enumerable.Empty().AsQueryable();
// }
// });
// return temp;
//}
#endregion
#endregion
#region IEnumerable的扩展方法
#region 将集合展开分别转换成字符串，再以指定分隔字符串链接，拼成一个字符串返回
///
/// 将集合展开分别转换成字符串，再以指定分隔字符串链接，拼成一个字符串返回
///
/// 动态类型
/// 拼接后的字符串
public static string ExpandAndToString(this IEnumerable collection, string separator)
{
List source = collection as List ?? collection.ToList();
if (source.IsEmpty())
{
return "";
}
string result = source.Cast()
.Aggregate(null, (current, o) => current + String.Format("{0}{1}", o, separator));
return result.Substring(0, result.LastIndexOf(separator, StringComparison.Ordinal));
}
#endregion
#region 根据指定条件返回集合中不重复的元素
///
/// 根据指定条件返回集合中不重复的元素
///
/// 动态类型
/// 动态筛选条件类型
/// 不重复元素的集合
public static IEnumerable DistinctBy(this IEnumerable source, Func keySelector)
{
//取分组集合中每组的第一条数据
return source.GroupBy(keySelector).Select(group => group.First());
}
#endregion
#region 根据第三方条件是否为真是否执行指定条件的查询
///
/// 根据第三方条件是否为真是否执行指定条件的查询
///
/// 动态类型
/// 查询的结果
public static IEnumerable WhereIf(this IEnumerable source, Func where,
bool condition)
{
return condition ? source.Where(where) : source;
}
#endregion
#region 判断集合是否为空
///
/// 判断集合是否为空
///
/// 动态类型
/// 集合为空返回true 不为空返回false
public static bool IsEmpty(this IEnumerable collection)
{
return !collection.Any();
}
#endregion
#endregion
#region 其他
///
/// 扩展Between 操作符
/// 使用 var query = db.People.Between(person => person.Age, 18, 21);
///
/// Between(this IQueryable source, Expression> keySelector, TKey low, TKey high) where TKey : IComparable
{
Expression key = Expression.Invoke(keySelector, keySelector.Parameters.ToArray());
Expression lowerBound = Expression.GreaterThanOrEqual(key, Expression.Constant(low));
Expression upperBound = Expression.LessThanOrEqual(key, Expression.Constant(high));
Expression and = Expression.AndAlso(lowerBound, upperBound);
Expression> lambda = Expression.Lambda>(and, keySelector.Parameters);
return source.Where(lambda);
}
///
/// In
///
/// (this T value, params T[] values)
{
return values.Contains(value);
}
///
/// Between
///
/// (this T i, T start, T end) where T : IComparable
{
return i.CompareTo(start) >= 0 && i.CompareTo(end) <= 0;
}
///
/// And
///
///
/// Or
///
///
