Dynamic WHERE clause in LINQ

user_86555 0
Viewed 139502

What is the best way to assemble a dynamic WHERE clause to a LINQ statement?

I have several dozen checkboxes on a form and am passing them back as: Dictionary<string, List<string>> (Dictionary<fieldName,List<values>>) to my LINQ query.

public IOrderedQueryable<ProductDetail> GetProductList(string productGroupName, string productTypeName, Dictionary<string,List<string>> filterDictionary)
{
    var q = from c in db.ProductDetail
            where c.ProductGroupName == productGroupName && c.ProductTypeName == productTypeName
            // insert dynamic filter here
            orderby c.ProductTypeName
            select c;
    return q;
}
where-clause dynamic linq c#
10 Answers
Thomas_Stock_728590
user_997250

It seems much simpler and simpler to use the ternary operator to decide dynamically if a condition is included

List productList = new List();

        productList =
                db.ProductDetail.Where(p => p.ProductDetailID > 0 //Example prop
                && (String.IsNullOrEmpty(iproductGroupName) ? (true):(p.iproductGroupName.Equals(iproductGroupName)) ) //use ternary operator to make the condition dynamic
                && (ID == 0 ? (true) : (p.ID == IDParam))
                ).ToList();
user_110988610

Just to share my idea for this case.

Another approach by solution is:


public IOrderedQueryable GetProductList(string productGroupName, string productTypeName, Dictionary> filterDictionary)
{
    return db.ProductDetail
        .where
        (
            p =>
            (
                (String.IsNullOrEmpty(productGroupName) || c.ProductGroupName.Contains(productGroupName))
                && (String.IsNullOrEmpty(productTypeName) || c.ProductTypeName.Contains(productTypeName))
                // Apply similar logic to filterDictionary parameter here !!!
            )
        );  
}

This approach is very flexible and allow with any parameter to be nullable.

user_63471920
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