if...then to concat SQL queries, equivalent in LINQ - VB NET

Question

I have simply code:

 Dim query as string = "SELECT id, red, yel, gre FROM table WHERE"
 if a then query=query + " red=true OR"
 if b then query=query + " yel=true OR"
 if c then query=query + " gre=true"
 if right(query,2)="OR" then query=left(query,len(query)-3)

How to make equivalent in LINQ ?

Update: (I need OR operator not AND like many other examples on the site)

Hasan Gholamali · Accepted Answer · 2018-05-17T16:57:36.593

-1

If a,b and c are Boolean variables the below code works:

Dim result = dbContext.Table();
result = result.Where(Function(r) (a And r.red) Or (b And r.yel) Or (c And r.gre));
result = result.ToList();

But if you mean a,b and c are logic clauses and you are using .net method like .ToString() in them you have to change the code like below:

Dim result = dbContext.Table().ToList();
result = result.Where(Function(r) (a And r.red) Or (b And r.yel) Or (c And r.gre));

Because .net methods can't run on dbcontext, first call ToList() to transmit data and after that you can use all .Net method on transmited data.

edited May 17 '18 at 16:57

answered May 17 '18 at 11:53

Hasan Gholamali

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Does this connect "WHERE" with AND operators not OR? – CzarnyLewis May 17 '18 at 13:39
You are right, I edited my answer – Hasan Gholamali May 17 '18 at 14:09
a,b,c are logic clause. How it will be look in VB NET? – CzarnyLewis May 17 '18 at 15:38
just syntax changes – Hasan Gholamali May 17 '18 at 16:54

if...then to concat SQL queries, equivalent in LINQ - VB NET

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