C# 如何通过StartWith在两个列表之间进行linq到nhibernate
我需要NHibernate 4运行此查询:C# 如何通过StartWith在两个列表之间进行linq到nhibernate,c#,linq,nhibernate,linq-to-nhibernate,C#,Linq,Nhibernate,Linq To Nhibernate,我需要NHibernate 4运行此查询: var filterList = new List<string> { "1" , "2" } ; var q = SessionInstance.Query<Book>() .Where(x => filterList.Any(s => s.StartsWith(x.Code))); var list = q.ToList(); 未实现此功能,但我们可以将此类WHERE条件转换为或表达式:
var filterList = new List<string> { "1" , "2" } ;
var q = SessionInstance.Query<Book>()
.Where(x => filterList.Any(s => s.StartsWith(x.Code)));
var list = q.ToList();
未实现此功能,但我们可以将此类WHERE条件转换为或表达式:
var q = SessionInstance
.Query<Book>()
//.Where(x => filterList.Any(s => s.StartsWith(x.Code)))
.Where(x => x.Code.StartsWith("1")
|| x.Code.StartsWith("2")
)
;
以及扩展本身:
public static Expression<Func<T, bool>> AnyStarts<T>(
this IList<string> startsWithValues, Expression<Func<T, string>> property)
{
var nothingToDo = startsWithValues == null
|| startsWithValues.Count == 0
|| property == null;
// nothing to process here, return null
if (nothingToDo)
{
return null;
}
// first value ...
string firstValue = startsWithValues.First();
Expression<Func<T, bool>> predicate =
x => property.Invoke(x).StartsWith(firstValue);
Expression<Func<T, bool>> result = predicate.Expand();
if (startsWithValues.Count == 1)
{
// first value is enough
return result;
}
// let's append Or if there are many string values
for (int index = 1; index < startsWithValues.Count; index++)
{
string nextValue = startsWithValues[index];
predicate = x => result.Invoke(x)
|| property.Invoke(x).StartsWith(nextValue);
result = predicate.Expand();
}
return result;
}
公共静态表达式AnyStarts(
此IList启动时使用值,表达式属性)
{
var nothingToDo=startsWithValues==null
||startsWithValues.Count==0
||属性==null;
//此处无需处理,返回null
如果(无提示)
{
返回null;
}
//第一个值。。。
string firstValue=startsWithValues.First();
表达式谓词=
x=>property.Invoke(x).StartsWith(firstValue);
表达式结果=predicate.Expand();
if(startsWithValues.Count==1)
{
//第一个值就足够了
返回结果;
}
//如果有许多字符串值,让我们附加Or
对于(int index=1;indexresult.Invoke(x)
||property.Invoke(x).StartsWith(nextValue);
结果=predicate.Expand();
}
返回结果;
}
我们可以这样称呼它:
var filterList = new List<string> { "1" , "2" }; // or more
var q = SessionInstance
.Query<Book>()
//.Where(x => filterList.Any(s => s.StartsWith(x.Code)))
.Where(filterList.AnyStarts<Contact>(x => x.Code))
;
var filterList=新列表{“1”,“2”};//或更多
var q=会话持续时间
.Query()
//.Where(x=>filterList.Any(s=>s.StartsWith(x.Code)))
.Where(filterList.AnyStarts(x=>x.Code))
;
我们将收到任何代码以“1”、“2”开头的书
public static Expression<Func<T, bool>> AnyStarts<T>(
this IList<string> startsWithValues, Expression<Func<T, string>> property)
{
var nothingToDo = startsWithValues == null
|| startsWithValues.Count == 0
|| property == null;
// nothing to process here, return null
if (nothingToDo)
{
return null;
}
// first value ...
string firstValue = startsWithValues.First();
Expression<Func<T, bool>> predicate =
x => property.Invoke(x).StartsWith(firstValue);
Expression<Func<T, bool>> result = predicate.Expand();
if (startsWithValues.Count == 1)
{
// first value is enough
return result;
}
// let's append Or if there are many string values
for (int index = 1; index < startsWithValues.Count; index++)
{
string nextValue = startsWithValues[index];
predicate = x => result.Invoke(x)
|| property.Invoke(x).StartsWith(nextValue);
result = predicate.Expand();
}
return result;
}
var filterList = new List<string> { "1" , "2" }; // or more
var q = SessionInstance
.Query<Book>()
//.Where(x => filterList.Any(s => s.StartsWith(x.Code)))
.Where(filterList.AnyStarts<Contact>(x => x.Code))
;