How to Evaluate Func with use EF.Functions?

Question

I'm trying to evaluate func<T, bool> with EF.Functions.Like in CSharpScript.EvaluateAsync, But I have an error in run time (The name 'EF' does not exist in the current context) when call GetPredicate() method.

Create Func Method:

public static class Helper
{
    public static async Task<Func<T, bool>> GetPredicate<T>(string stringExpression)
            {
                ScriptOptions options = ScriptOptions.Default.AddReferences(references: typeof(T).Assembly);
                Func<T, bool> discountFilterExpression = await CSharpScript.EvaluateAsync<Func<T, bool>>(stringExpression, options);

                return discountFilterExpression;
            }
}

Call Method:

string expString = "x => EF.Functions.Like(x.CodeId, pattern) || EF.Functions.Like(x.Name, pattern) || EF.Functions.Like(x.CategoryId, pattern)";
Func<MyClass, bool> exp = await Helper.GetPredicate<MyClass>(expString);

How to do this?

score 3 · Accepted Answer · answered Apr 08 '19 at 14:41

EF.Functions usually are not supposed to be evaluated.

But to answer your concrete question, you need to add both reference to Microsoft.EntityFrameworkCore assembly and import (using) of Microsoft.EntityFrameworkCore namespace, e.g.

ScriptOptions options = ScriptOptions.Default
    .AddReferences(references: typeof(T).Assembly)
    .AddReferences(typeof(EF).Assembly) // <--
    .AddImports(typeof(EF).Namespace); // <--

How to Evaluate Func with use EF.Functions?

1 Answers1