Getting exception while trying to compare enum(converted to string) and a string value obtained from search

Question

Getting

System.InvalidOperationException: 'The LINQ expression 'DbSet Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to either AsEnumerable(), AsAsyncEnumerable()

while trying to compare two values - an enum(by converting to string) and a string keyword which I get from a search form in .NET 3 API

 query = query.Where(it => it.EnumType.ToString().ToLower().StartsWith(keyword.ToLower()); 

Help is appreciated.

Answer 1

Instead of doing this

it => it.EnumType.ToString()

I would suggest you do it the other way around by try converting

keyword.ToLower()

to enum. You can try something like this.

private static bool IsDefined<T>(string value)
{
    return Enum.IsDefined(typeof(T), value);
}
public static T GetEnumByString<T>(string value)
{
    return (T)Enum.Parse(typeof(T), value);
}

and then write the expression like this:

if (IsDefined<YourEnum>(keyword))
{
    query = query.Where(it => it.EnumType == GetEnumByString<YourEnum>(keyword)); 
}