How to Dynamically Build WHERE Clauses in LINQ Queries?

Dynamic construction of WHERE clause in LINQ

When building a LINQ query, you may need to dynamically assemble the WHERE clause based on user input or runtime conditions. This is especially useful when dealing with complex filters or dynamic data selection.

For example, let's say you have a form with a number of checkboxes that you pass as a dictionary of field names and their corresponding values. In order to incorporate this dynamic filtering into a LINQ query, you can use the chaining method demonstrated in the provided code example.

var q = from c in db.ProductDetail
        where c.ProductGroupName == productGroupName && c.ProductTypeName == productTypeName
        select c;

foreach (var filterPair in filterDictionary)
{
    q = q.Where(c => filterPair.Value.Contains(c.GetPropertyValue(filterPair.Key)));
}

q = q.OrderBy(c => c.ProductTypeName);

In this example, the filterDictionary is iterated over, and for each filter pair (key-value pair), a new WHERE clause is added to the query. Call the GetPropertyValue method to dynamically retrieve the property value of the specified fieldName.

Alternatively, you can chain the WHERE clause directly in the initial query statement, as shown in the sample code provided in the solution.

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