CODEWITHSUNDEEP
linqentity-frameworklinq-to-entities
Jarmez De La Rocha
Jarmez De La Rocha

Reputation: 670

Create a Dynamic Entity Framework Where Query

At runtime I have a dynamic list of "Parent" ids i need to query against one of my entity tables, using LINQ how would I generate the query at run time? Currently am (VERY SLOWLY) looping over my list of ID's and performing a separate query to the database using the Where method. Is there an API that will allow me to build a single WHERE statement that in essence is appending "&& value = something" as I would have if I was writing the SQL myself?

Currently what i do looks like this 

            foreach(var parent in parents)
        {
            col.AddRange(context.LocalAuthorities.Where(c => c.Parent.ID == parent.ID).ToList());
        }

Upvotes: 0

Views: 53

Answers (1)

JimiLoe
JimiLoe

Reputation: 978

If your goal is to replace multiple iterative queries by one query, you can use this approach:

var allParentIds = parents.Select(p=>p.ID).ToList();
var result = context.LocalAuthorities.Where(c=> allParentIds.Contains(c.Parent.ID));

col.AddRange(result);

Upvotes: 1

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