LINQ to SQL的情况下查询
-
22-07-2019 - |
题
林具有建立与LINQ to SQL的数据查询表达式C#中的查询的问题。
什么我想最终不正是基于这种伪代码表达。
public IQueryable<CTest> searchRecords(string category, string searchString, DateTime startDate, DateTime endDate, int searchType, int searchType2)
{
//-Search All Records
//-From the information table
//-By the category column containing a specific search
//-Also by
// ~if both a startDate and endDate are entered (not (0000,00,00) OR null) then get records
// by this expression
// ~else then don't worry about this statement
//-Also by
// ~if a searchType is equal zero(0) then search for records from the
// search_type table equal to zero(0)
// ~if a searchType is equal one(1) then search for records from the
// search_type table equal to one(1)
// ~else then don't worry about this statement
//-Also by
// ~if a searchType2 is equal zero(0) then search for records from the
// search_type table equal to zero(0)
// ~if a searchType2 is equal one(1) then search for records from the
// search_type table equal to one(1)
// ~else then don't worry about this statement
//Here is my attempt at it
/*
var table = db.table1;
switch (category)
{
case "_category1":
var records =
from c in table
where c.column1.ToString().Contains(searchString)
select new CTest
{
test_id = c.id,
test_name = c.name,
test_number = c.number,
date = ((startDate != null) && (endDate != null)) ? ((c.test_date >= startDate) && (c.test_date <= endDate)) :
c.test_date),
test_type = (searchType == 0 ? (c.searchType = 0) :
searchType == 1 ? (c.searchType = 1) :
c.searchType),
test_type2 = (searchType2 == 0 ? (c.searchType2 = 0) :
searchType2 == 1 ? (c.searchType2 = 1) :
c.searchType2)
};
break;
default:
break;
}
*/
}
预先感谢。
解决方案
这会更容易与扩展方法比LINQ语法做:
var records = context.Table
.Where( c => c.column1.Contains( searchString ) );
if (startDate != null && endDate != null)
{
records = records.Where( c => c.test_date >= startDate
&& c.test_date <= endDate );
}
...
,你走这将建立的LINQ表达。评价被延迟,直到实际调用一些扩展,需要选择将被执行,如COUNT()或ToList(),或枚举结果的元素。
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