Linq where expressions as values to add












0














I have a question about formatting LINQ query



I have the same query with different where options



For example: 



var result = context.table.Include(x => x.table2).Where(q => q1);


The query is the same but in different situations I have different where expressions like q1,q2,q3



Can I configure the q objects separately and use it in the query like



var q1 = (q => q.x == "something");

var q2 = (q => q.x == "something2");

var q3 = (q => q.x == "something3");



var qx;

if(x)

{

    qx = q1;

}

if(y)

{

    qx = q2;

}



var result = context.table.Include(x => x.table2).Where(q => qx);





c# linq .net-4.5







share|improve this question




















  • 1




    Why not try it out? Basically you can do this, however you have to declare qx outside the if-statements.
    – HimBromBeere
    Nov 13 '18 at 9:11








  • 1




    Why not just assign the value of the string?
    – mshwf
    Nov 13 '18 at 9:11












  • Why not put them all as OR condition
    – Rahul
    Nov 13 '18 at 9:19






  • 1




    @Rahul That´s completely different. In this case you would fetch all elements that have any of the three values.
    – HimBromBeere
    Nov 13 '18 at 9:21
















0














I have a question about formatting LINQ query



I have the same query with different where options



For example: 



var result = context.table.Include(x => x.table2).Where(q => q1);


The query is the same but in different situations I have different where expressions like q1,q2,q3



Can I configure the q objects separately and use it in the query like



var q1 = (q => q.x == "something");

var q2 = (q => q.x == "something2");

var q3 = (q => q.x == "something3");



var qx;

if(x)

{

    qx = q1;

}

if(y)

{

    qx = q2;

}



var result = context.table.Include(x => x.table2).Where(q => qx);





c# linq .net-4.5







share|improve this question




















  • 1




    Why not try it out? Basically you can do this, however you have to declare qx outside the if-statements.
    – HimBromBeere
    Nov 13 '18 at 9:11








  • 1




    Why not just assign the value of the string?
    – mshwf
    Nov 13 '18 at 9:11












  • Why not put them all as OR condition
    – Rahul
    Nov 13 '18 at 9:19






  • 1




    @Rahul That´s completely different. In this case you would fetch all elements that have any of the three values.
    – HimBromBeere
    Nov 13 '18 at 9:21














0












0








0







I have a question about formatting LINQ query



I have the same query with different where options



For example: 



var result = context.table.Include(x => x.table2).Where(q => q1);


The query is the same but in different situations I have different where expressions like q1,q2,q3



Can I configure the q objects separately and use it in the query like



var q1 = (q => q.x == "something");

var q2 = (q => q.x == "something2");

var q3 = (q => q.x == "something3");



var qx;

if(x)

{

    qx = q1;

}

if(y)

{

    qx = q2;

}



var result = context.table.Include(x => x.table2).Where(q => qx);





c# linq .net-4.5







share|improve this question















I have a question about formatting LINQ query



I have the same query with different where options



For example: 



var result = context.table.Include(x => x.table2).Where(q => q1);


The query is the same but in different situations I have different where expressions like q1,q2,q3



Can I configure the q objects separately and use it in the query like



var q1 = (q => q.x == "something");

var q2 = (q => q.x == "something2");

var q3 = (q => q.x == "something3");



var qx;

if(x)

{

    qx = q1;

}

if(y)

{

    qx = q2;

}



var result = context.table.Include(x => x.table2).Where(q => qx);





c# linq .net-4.5




c# linq .net-4.5






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 13 '18 at 9:56









Tsahi Asher

1,133822




1,133822










asked Nov 13 '18 at 9:08









Leon BarkanLeon Barkan

2,02321028




2,02321028








  • 1




    Why not try it out? Basically you can do this, however you have to declare qx outside the if-statements.
    – HimBromBeere
    Nov 13 '18 at 9:11








  • 1




    Why not just assign the value of the string?
    – mshwf
    Nov 13 '18 at 9:11












  • Why not put them all as OR condition
    – Rahul
    Nov 13 '18 at 9:19






  • 1




    @Rahul That´s completely different. In this case you would fetch all elements that have any of the three values.
    – HimBromBeere
    Nov 13 '18 at 9:21














  • 1




    Why not try it out? Basically you can do this, however you have to declare qx outside the if-statements.
    – HimBromBeere
    Nov 13 '18 at 9:11








  • 1




    Why not just assign the value of the string?
    – mshwf
    Nov 13 '18 at 9:11












  • Why not put them all as OR condition
    – Rahul
    Nov 13 '18 at 9:19






  • 1




    @Rahul That´s completely different. In this case you would fetch all elements that have any of the three values.
    – HimBromBeere
    Nov 13 '18 at 9:21








1




1




Why not try it out? Basically you can do this, however you have to declare qx outside the if-statements.
– HimBromBeere
Nov 13 '18 at 9:11






Why not try it out? Basically you can do this, however you have to declare qx outside the if-statements.
– HimBromBeere
Nov 13 '18 at 9:11






1




1




Why not just assign the value of the string?
– mshwf
Nov 13 '18 at 9:11






Why not just assign the value of the string?
– mshwf
Nov 13 '18 at 9:11














Why not put them all as OR condition
– Rahul
Nov 13 '18 at 9:19




Why not put them all as OR condition
– Rahul
Nov 13 '18 at 9:19




1




1




@Rahul That´s completely different. In this case you would fetch all elements that have any of the three values.
– HimBromBeere
Nov 13 '18 at 9:21




@Rahul That´s completely different. In this case you would fetch all elements that have any of the three values.
– HimBromBeere
Nov 13 '18 at 9:21












4 Answers
4






active

oldest

votes


















0














Not precisely. You would need to do something like



var result = context.table.Include(x => x.table2).Where(qx);


because q1, q2 etc. are already expressions compatible with what .Where() expects.






share|improve this answer





























    0














    IQueryable.Where accepts an Expression<Func<TSource, bool>>, you can do something like this:



    Expression<Func<SourceType, bool>> qx = q => false;
    
Expression<Func<SourceType, bool>> q1 = q => q.x == "something";





    share|improve this answer





























      0














      Just to note before my answer, you can't declare qx like this:



      var qx;



      because the compiler won't resolve a type right away.
      And what you are asking is possible if you specify the type that q is.



      Func<type, bool> q1 = (type q) => q.x == "something";
      
Func<type, bool> q2 = (type q) => q.x == "something2";
      
Func<type, bool> q3 = (type q) => q.x == "something3";
      

      
Func<type, bool> qx = q3; //this needs a value (if x and y are false)
      
if(x)
      
{
      
   qx = q1;
      
}
      
if(y)
      
{
      
   qx = q2;
      
}
      

      
var result = context.table.Include(x => x.table2).Where(qx);





      share|improve this answer





















      • The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
        – Tsahi Asher
        Nov 13 '18 at 12:28










      • You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
        – Daniel Loudon
        Nov 13 '18 at 12:34










      • I totally agree. That's why I don't use it often.
        – Tsahi Asher
        Nov 13 '18 at 13:40



















      -1














      You seem to need a query where the actual condition is provided at runtime. Just use a Predicate:



      Predicate<MyType> predicate;
      
if(x)
      
{
      
    predicate = q => q.x == "something";
      
}
      
else if(y)
      
{
      
    predicate = q => q.x == "something2";
      
}
      
else
      
    predicate = q => q.x == "something3";
      
var result = context.table.Include(x => x.table2).where(predicate);





      share|improve this answer























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        4 Answers
        4






        active

        oldest

        votes








        4 Answers
        4






        active

        oldest

        votes









        active

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        votes






        active

        oldest

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        0














        Not precisely. You would need to do something like



        var result = context.table.Include(x => x.table2).Where(qx);


        because q1, q2 etc. are already expressions compatible with what .Where() expects.






        share|improve this answer


























          0














          Not precisely. You would need to do something like



          var result = context.table.Include(x => x.table2).Where(qx);


          because q1, q2 etc. are already expressions compatible with what .Where() expects.






          share|improve this answer
























            0












            0








            0






            Not precisely. You would need to do something like



            var result = context.table.Include(x => x.table2).Where(qx);


            because q1, q2 etc. are already expressions compatible with what .Where() expects.






            share|improve this answer












            Not precisely. You would need to do something like



            var result = context.table.Include(x => x.table2).Where(qx);


            because q1, q2 etc. are already expressions compatible with what .Where() expects.







            share|improve this answer












            share|improve this answer



            share|improve this answer










            answered Nov 13 '18 at 9:12









            Tsahi AsherTsahi Asher

            1,133822




            1,133822

























                0














                IQueryable.Where accepts an Expression<Func<TSource, bool>>, you can do something like this:



                Expression<Func<SourceType, bool>> qx = q => false;
                
Expression<Func<SourceType, bool>> q1 = q => q.x == "something";





                share|improve this answer


























                  0














                  IQueryable.Where accepts an Expression<Func<TSource, bool>>, you can do something like this:



                  Expression<Func<SourceType, bool>> qx = q => false;
                  
Expression<Func<SourceType, bool>> q1 = q => q.x == "something";





                  share|improve this answer
























                    0












                    0








                    0






                    IQueryable.Where accepts an Expression<Func<TSource, bool>>, you can do something like this:



                    Expression<Func<SourceType, bool>> qx = q => false;
                    
Expression<Func<SourceType, bool>> q1 = q => q.x == "something";





                    share|improve this answer












                    IQueryable.Where accepts an Expression<Func<TSource, bool>>, you can do something like this:



                    Expression<Func<SourceType, bool>> qx = q => false;
                    
Expression<Func<SourceType, bool>> q1 = q => q.x == "something";






                    share|improve this answer












                    share|improve this answer



                    share|improve this answer










                    answered Nov 13 '18 at 9:23









                    mshwfmshwf

                    2,13742049




                    2,13742049























                        0














                        Just to note before my answer, you can't declare qx like this:



                        var qx;



                        because the compiler won't resolve a type right away.
                        And what you are asking is possible if you specify the type that q is.



                        Func<type, bool> q1 = (type q) => q.x == "something";
                        
Func<type, bool> q2 = (type q) => q.x == "something2";
                        
Func<type, bool> q3 = (type q) => q.x == "something3";
                        

                        
Func<type, bool> qx = q3; //this needs a value (if x and y are false)
                        
if(x)
                        
{
                        
   qx = q1;
                        
}
                        
if(y)
                        
{
                        
   qx = q2;
                        
}
                        

                        
var result = context.table.Include(x => x.table2).Where(qx);





                        share|improve this answer





















                        • The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
                          – Tsahi Asher
                          Nov 13 '18 at 12:28










                        • You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
                          – Daniel Loudon
                          Nov 13 '18 at 12:34










                        • I totally agree. That's why I don't use it often.
                          – Tsahi Asher
                          Nov 13 '18 at 13:40
















                        0














                        Just to note before my answer, you can't declare qx like this:



                        var qx;



                        because the compiler won't resolve a type right away.
                        And what you are asking is possible if you specify the type that q is.



                        Func<type, bool> q1 = (type q) => q.x == "something";
                        
Func<type, bool> q2 = (type q) => q.x == "something2";
                        
Func<type, bool> q3 = (type q) => q.x == "something3";
                        

                        
Func<type, bool> qx = q3; //this needs a value (if x and y are false)
                        
if(x)
                        
{
                        
   qx = q1;
                        
}
                        
if(y)
                        
{
                        
   qx = q2;
                        
}
                        

                        
var result = context.table.Include(x => x.table2).Where(qx);





                        share|improve this answer





















                        • The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
                          – Tsahi Asher
                          Nov 13 '18 at 12:28










                        • You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
                          – Daniel Loudon
                          Nov 13 '18 at 12:34










                        • I totally agree. That's why I don't use it often.
                          – Tsahi Asher
                          Nov 13 '18 at 13:40














                        0












                        0








                        0






                        Just to note before my answer, you can't declare qx like this:



                        var qx;



                        because the compiler won't resolve a type right away.
                        And what you are asking is possible if you specify the type that q is.



                        Func<type, bool> q1 = (type q) => q.x == "something";
                        
Func<type, bool> q2 = (type q) => q.x == "something2";
                        
Func<type, bool> q3 = (type q) => q.x == "something3";
                        

                        
Func<type, bool> qx = q3; //this needs a value (if x and y are false)
                        
if(x)
                        
{
                        
   qx = q1;
                        
}
                        
if(y)
                        
{
                        
   qx = q2;
                        
}
                        

                        
var result = context.table.Include(x => x.table2).Where(qx);





                        share|improve this answer












                        Just to note before my answer, you can't declare qx like this:



                        var qx;



                        because the compiler won't resolve a type right away.
                        And what you are asking is possible if you specify the type that q is.



                        Func<type, bool> q1 = (type q) => q.x == "something";
                        
Func<type, bool> q2 = (type q) => q.x == "something2";
                        
Func<type, bool> q3 = (type q) => q.x == "something3";
                        

                        
Func<type, bool> qx = q3; //this needs a value (if x and y are false)
                        
if(x)
                        
{
                        
   qx = q1;
                        
}
                        
if(y)
                        
{
                        
   qx = q2;
                        
}
                        

                        
var result = context.table.Include(x => x.table2).Where(qx);






                        share|improve this answer












                        share|improve this answer



                        share|improve this answer










                        answered Nov 13 '18 at 10:18









                        Daniel LoudonDaniel Loudon

                        678116




                        678116












                        • The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
                          – Tsahi Asher
                          Nov 13 '18 at 12:28










                        • You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
                          – Daniel Loudon
                          Nov 13 '18 at 12:34










                        • I totally agree. That's why I don't use it often.
                          – Tsahi Asher
                          Nov 13 '18 at 13:40


















                        • The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
                          – Tsahi Asher
                          Nov 13 '18 at 12:28










                        • You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
                          – Daniel Loudon
                          Nov 13 '18 at 12:34










                        • I totally agree. That's why I don't use it often.
                          – Tsahi Asher
                          Nov 13 '18 at 13:40
















                        The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
                        – Tsahi Asher
                        Nov 13 '18 at 12:28




                        The var issue is my fault. Initially it was declared inside the if blocks, making it out of scope for the last line, so I moved it Up. I don't use var very often.
                        – Tsahi Asher
                        Nov 13 '18 at 12:28












                        You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
                        – Daniel Loudon
                        Nov 13 '18 at 12:34




                        You should explicity write the type, its best practice. var is really meant for anonymous classes and querys, although nothing wrong with it if you can read it
                        – Daniel Loudon
                        Nov 13 '18 at 12:34












                        I totally agree. That's why I don't use it often.
                        – Tsahi Asher
                        Nov 13 '18 at 13:40




                        I totally agree. That's why I don't use it often.
                        – Tsahi Asher
                        Nov 13 '18 at 13:40











                        -1














                        You seem to need a query where the actual condition is provided at runtime. Just use a Predicate:



                        Predicate<MyType> predicate;
                        
if(x)
                        
{
                        
    predicate = q => q.x == "something";
                        
}
                        
else if(y)
                        
{
                        
    predicate = q => q.x == "something2";
                        
}
                        
else
                        
    predicate = q => q.x == "something3";
                        
var result = context.table.Include(x => x.table2).where(predicate);





                        share|improve this answer




























                          -1














                          You seem to need a query where the actual condition is provided at runtime. Just use a Predicate:



                          Predicate<MyType> predicate;
                          
if(x)
                          
{
                          
    predicate = q => q.x == "something";
                          
}
                          
else if(y)
                          
{
                          
    predicate = q => q.x == "something2";
                          
}
                          
else
                          
    predicate = q => q.x == "something3";
                          
var result = context.table.Include(x => x.table2).where(predicate);





                          share|improve this answer


























                            -1












                            -1








                            -1






                            You seem to need a query where the actual condition is provided at runtime. Just use a Predicate:



                            Predicate<MyType> predicate;
                            
if(x)
                            
{
                            
    predicate = q => q.x == "something";
                            
}
                            
else if(y)
                            
{
                            
    predicate = q => q.x == "something2";
                            
}
                            
else
                            
    predicate = q => q.x == "something3";
                            
var result = context.table.Include(x => x.table2).where(predicate);





                            share|improve this answer














                            You seem to need a query where the actual condition is provided at runtime. Just use a Predicate:



                            Predicate<MyType> predicate;
                            
if(x)
                            
{
                            
    predicate = q => q.x == "something";
                            
}
                            
else if(y)
                            
{
                            
    predicate = q => q.x == "something2";
                            
}
                            
else
                            
    predicate = q => q.x == "something3";
                            
var result = context.table.Include(x => x.table2).where(predicate);






                            share|improve this answer














                            share|improve this answer



                            share|improve this answer








                            edited Nov 13 '18 at 9:19

























                            answered Nov 13 '18 at 9:14









                            HimBromBeereHimBromBeere

                            23.1k43159




                            23.1k43159






























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                                Thiostrepton

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                                Thiostrepton [1] Names Other names Alaninamide, Bryamycin, Thiactin Identifiers CAS Number 1393-48-2   Y 3D model (JSmol) Interactive image ChEMBL ChEMBL468719   N ECHA InfoCard 100.014.304 PubChem CID 16130278 InChI InChI=1S/C72H85N19O18S5/c1-14-26(3)47-63(105)78-30(7)57(99)75-28(5)56(98)76-31(8)58(100)91-72-19-18-40(66-85-43(22-111-66)59(101)77-29(6)55(97)74-27(4)54(73)96)81-52(72)42-21-112-67(83-42)49(34(11)109-69(107)41-20-37(32(9)92)36-16-17-39(79-47)51(95)50(36)80-41)89-60(102)44-24-113-68(86-44)53(71(13,108)35(12)94)90-62(104)45-23-110-65(84-45)38(15-2)82-64(106)48(33(10)93)88-61(103)46-25-114-70(72)87-46/h15-17,20-22,24-26,30-35,39,45,47-49,51-53,79,92-95,108H,4-6,14,18-19,23H2,1-3,7-13H3,(H2,73,96)(H,74,97)(H,75,99)(H,76,98)(H,77,101)(H,78,105)(H,82,106)(H,88,103)(H,89,102)(H,90,104)(H,91,100)/b38-15-/t26-,30-,31-,32-,33+,34+,35+,39+,45+,47-,48-,49-,51-,52+,53+,71+,72+/m0/s1 Key: NSFFHOGKXHRQEW-AIHSUZKVSA-N ...
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                                Caerphilly

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                                This article is about the town of Caerphilly. For the cheese of the same name, see Caerphilly cheese. For other uses, see Caerphilly (disambiguation). Caerphilly Welsh: Caerffili Caerphilly Castle Caerphilly Location within Caerphilly Population 30,388  OS grid reference ST1586 Principal area Caerphilly Ceremonial county Gwent Country Wales Sovereign state United Kingdom Post town CAERPHILLY Postcode district CF83 Dialling code 029 Police Gwent Fire South Wales Ambulance Welsh EU Parliament Wales UK Parliament Caerphilly Welsh Assembly Caerphilly List of places UK Wales Caerphilly 51°34′41″N 3°13′05″W  /  51.578°N 3.218°W  / 51.578; -3.218 Coordinates: 51°34′41″N 3°13′05″W  /  51.578°N 3.218°W  / 51.578; -3.218 Caerphilly ( / k aɪər ˈ f ɪ l i / ; Welsh: Caerffili , Welsh pronunciation:  [ˌkɑːɨrˈfɪlɪ] ) is a town and community in South Wales, at the southern end of the Rhymney Valley....
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