How to make order by Column variable because I have a dropdown on page and I want to show grid according to sord order selected in this Dropdown e.g Price, Code, rating, description etc etc. and I donot want to write a separate query for each column.
from lm in lDc.tbl_Products
where lm.TypeRef == pTypeId
orderby lm.Code ascending
select new;
Assuming you want to do the sorting via SQL then you will need to pass in the sort column/type. The query is deferred until you actually do the select so you can build up the query in steps and once you are done execute it like so:
// Do you query first. This will NOT execute in SQL yet.
var query = lDC.tbl_Products.Where(p => p.TypeRef == pTypeId);
// Now add on the sort that you require... you could do ascending, descending,
// different cols etc..
switch (sortColumn)
{
case "Price":
query = query.OrderBy(q => q.Price);
break;
case "Code":
query = query.OrderBy(q => q.Code);
break;
// etc...
}
// Now execute the query to get a result
var result = query.ToList();
If you want to do it outside of SQL then just get a basic result with no sorting and then apply an OrderBy to the result base on the sort criteria you need.
public static IEnumerable<T> OrderByIf<T,TKey>(this IEnumerable<T> source, bool condition, Func<T, TKey> keySelector)
{
return (condition) ? source.OrderBy(keySelector).AsEnumerable() : source;
}
Usage:
var query = lDC.tbl_Products.Where(p => p.TypeRef == pTypeId)
.OrderByIf(sortColumn == "Price", p => p.Price)
.OrderByIf(sortColumn == "Code", p => p.Code);
You can "build up" a LINQ query in separate steps.
Generate your base query to return the information unsorted. This query will not be executed until you try and enumerate the results.
var data = from lm in lDc.tbl_Products
where lm.TypeRef == pTypeId
select new;
Then in your event handler, apply whatever sorting you wish before binding the results to the grid.
var orderedData = from lm in data
order lm.Code ascending
select new;
// TODO: Display orderedData in a grid.
The full query you enumerate over is the one which will be evaluated. This means you can run a separate query for each item in your drop down, built from a "base" query.
