How to create a dynamic where clause?

c# dynamic-linq linq

Question

in this below code

string cluase = string.Empty;
string whereValue = string.Empty;

foreach (var i in whereCluaseItems)
{
    if (cluase != "")
    {
        cluase += " and " + i.Name;
    }
    else
    {
        cluase = i.Name;
    }
    if (whereValue != "")
    {
        whereValue += "," + i.Value;
    }
    else
    {
        whereValue = i.Value;
    }
}

var result = context.vCatalogItemsDetails
                    .Where(cluase, whereValue) 
// since where syntax has to be like this : where("@landuageID=@0,categoryid=@1", 1,1)
.OrderBy("itemID")
.Skip((pageN - 1) * 10).Take(10);

cluase is a string and it contains "languageId=@0, categoryid=@1"

whereValue is also a string and it contains "1,1"

i need to remove those quotation marks. how can i do it?

1
0
7/29/2014 6:56:44 AM

Fastest Entity Framework Extensions

Bulk Insert
Bulk Delete
Bulk Update
Bulk Merge

Popular Answer

For this kind of "dynamic" where clause, there is often no need to use expression based features. You just have to realize that multiple Where calls can be composed.

For example:

public static IEnumerable<Person> Filter(this IEnumerable<Person> source, 
    string firstname, string lastname)
{
    if (firstname != null)
    {
        source = from person in source
                 where person.Firstname.Contains(firstname)
                 select person;
    }

    if (lastname != null)
    {
        source = from person in source
                 where person.Lastname.Contains(lastname)
                 select person;
    }

    return source;
}

The same technique works with IQueryable<T> too.

1
7/29/2014 7:15:18 AM

Related Questions

Column names are provided at runtime in LINQ's dynamic where clause.

@Geoff has the best option, justing Dynamic LINQ....If you want to go the way of building queries at runtime using Lambda though I'd recomment that you use the PredicateBuilder (...http://www.albahari.com/nutshell/predicatebuilder.aspx...) and have something such as this:...Expression<Fun<T,bool>> pred = null; //delcare the predicate to start with....
.net dynamic-linq linq-to-sql
asked by Aaron Powell

Does dynamic GroupBy in dynamic LINQ work with dynamic Where?

Found it, ...db.Table1.AsQueryable()... fixed it, so ...db.Table1.AsQueryable().Where("it.FieldA>10").GroupBy("it.FieldB", "it").Select("key") ... works without exception....The problem was that Microsoft Dynamic Linq library extends ...IQueryable<Table1>..., so it does not take effect on... ObjectQuery<Table1>... which is the type of ...db.Table1....
.net dynamic dynamic-linq linq linq-to-entities
asked by alpav

Multiple table dynamic, Entity Data Model, Dynamic Linq Strongly typed return types, when clause

The solution to my particular query was to do this:... var query = from pl in CurrentDataSource.ProductListing join pla in CurrentDataSource.ProductListingAttribute on new {pl.ProductID, pl.WebCategoryID, pl.ParentProductID} equals new {pla.Pro...
anonymous-types c# dynamic-linq linq-to-entities
asked by rposbo

Linq Dynamic Error with Dynamic Where clause

The error points to the place where the LINQ query is evaluated and, as the message says, the problem is that a character is expected but several characters were provided....Check whenever ...ddl_AreaFilter.SelectedValue..., ...ddl_SubAreaFilter.SelectedValue... or ...ddl_AllocFilter.SelectedValue... actually contain a character or a string. If the...
dynamic-linq linq vb.net
asked by jnovo

Creating a dynamic Linq select clause from Expressions

So, we'll have a lot of steps here, but each individual step should be fairly short, self-contained, ...reusable..., and relatively understandable....The first thing we'll do is create a method that can combine expressions. What it will do is take an expression that accepts some input and generates an intermediate value. Then it will take a secon...
c# dynamic-linq linq linqkit linq-to-entities
asked by Servy

Query with dynamic where clause (concatenated array elements)

If you're testing for a property to be in an array, you can use the ...Contains... extension method on ...IEnumerable..., which is probably preferable to building a string. Try this:...Dim query = From element In dtImitate.Where(function (el) teamsArray.Contains(el.Team))
dynamic-linq linq vb.net
asked by tom.dietrich

Dynamic Linq Library can't handling one on many relationship in select clause

This should do it I think. ...var queryBuilder = (from q in db.Questions.Include(itm => itm.Answers) join a in db.Answers on q.QuestionID equals a.QuestionID where a.Email.equals(SearchCriteria) select q).Distinct().ToList(); var questionVM = new List<QuestionVM>(); foreach(var q in queryBuilder) { questionVM.add(new QuestionVM { Que...
asp.net dynamic-linq linq linq-expressions predicatebuilder
asked by Edwin van Vliet

Dynamic Linq 'contains' clause without using placeholder

try code:...int[] ids= {1,2,3,4}; dataContext.Table.Where(c=>c.ids.Contains(t.id)).ToList(); ...Or ...var result= (from p in dataContext.Table.AsEnumerable() join q in ids on p.id equals q select p).Distinct() .ToList();
asp.net asp.net-core-mvc c# dynamic-linq linq
asked by kari kalan

Select Clause using System.Linq.Dynamic is returning "'(' expected" fault

The main question from your example is "what is outerIt?" (...@1.Contains(outerIt.Id)...) This looks to be just a piece of a larger query. You may want to post up the complete set of expressions....Based on an assumption of what it looks like you are after: It may be possible within a single Linq statement, but often I hit weird-isms around Linq2En...
c# dynamic-linq linq linq-to-sql
asked by Steve Py

Dynamic linq query having error if where clause values contain double quote

I am working on dynamic linq query which generate Where Clause based on some business rules. ...It works if input string contains result without having a double quote characters but It throws error once it contains double quote....string WhereClauseV1 = "Name.Contains(\"stack overflow\")"; --> Works for -> stack overflow string WhereClasueV2 = "...
c# dynamic dynamic-linq linq
asked by Vishal

Fastest Entity Framework Extensions

Bulk Insert
Bulk Delete
Bulk Update
Bulk Merge
View more on Stack Overflow

Prime Library

Performance

Expression Evaluator

More Projects...
Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow
Licensed under: CC-BY-SA with attribution
Not affiliated with Stack Overflow