Challenge #1 - Solution 2 - StringFilterOptionsAttribute.cs

StringFİlterOptionsAttribute.cs

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false)]
public class StringFilterOptionsAttribute : FilteringOptionsBaseAttribute
{
    public StringFilterOptionsAttribute(StringFilterOption option)
    {
        this.Option = option;
    }

    public StringFilterOption Option { get; set; }
    public StringComparison StringComparison { get; set; } = StringComparison.InvariantCultureIgnoreCase;

    public override Expression BuildExpression(Expression expressionBody, PropertyInfo property, object value)
    {
        var method = typeof(string).GetMethod(Option.ToString(), types: new[] { typeof(string), typeof(StringComparison) });

        var comparison = Expression.Equal(
                    Expression.Call(
                        method: method,
                        instance: Expression.Property(expressionBody, property.Name),
                        arguments: new[] { Expression.Constant(value), Expression.Constant(StringComparison) }),
                    Expression.Constant(true)
            );

        return comparison;
    }