如何在EF中检查对象是否为空

Question

I am new to EF and trying to do a small project with it. I added a condition to EF but I am having a problem. My condition is all about IN condition like SQL, SELECT * FROM table1 WHERE col1 IN (1,2,3...)

Here is my EF....

var res3 = res2.Where(l => !slitDetail
                        .Any(s => s.BlockId == l.Id 
                               && s.WarehouseDepot.WarehouseDepotName != "Ara Ürün Depo" 
                               && s.WarehouseDepot.WarehouseDepotName != "Özel Kesim Depo"));

s.WarehouseDepot might be NULL sometimes which is normal, but if it is null, this query throws an exception.

How can I check if s.WarehouseDepot is null and make it work even if it is null?

Answer 1

There are 2 possiblities if s.WarehouseDepot == null

1) You want your Any to return true , in that case you could use something like

var res3 = res2.Where(l => !slitDetail
                        .Any(s => s.BlockId == l.Id
                               && s.WarehouseDepot != null
                                ? (s.WarehouseDepot.WarehouseDepotName != "Ara Ürün Depo" && s.WarehouseDepot.WarehouseDepotName != "Özel Kesim Depo") 
                                : true));

This would use the s.WarehouseDepot only if it has a value otherwise it would return true

2) You want your Any to return false . In this case you could simply replace the true by false in the above expression or use something like

var res3 = res2.Where(l => !slitDetail
                        .Any(s => s.BlockId == l.Id
                               && s.WarehouseDepot != null
                               && s.WarehouseDepot.WarehouseDepotName != "Ara Ürün Depo"
                               && s.WarehouseDepot.WarehouseDepotName != "Özel Kesim Depo"));

Note that both these outcomes will automatically consider the s.BlockId == l.Id condition too.