Question

I have a method that gets a list of objects and then returns all their properties values based on the attributes and types of the property.
I’m having difficulties with selecting the value because the Select depends on conditions.
What I did so far allows me to get the value in the ugliest way I have ever seen:

public IEnumerable<string> GetValues(List<ProperyInfo> objects)
{
     var allValues = new List<string>();
     foreach (var obj in objects)
     {
         // Get the PropertyInfo for the obj
         var properties = GetPropertiesWithTheAttributes(obj);
         var values = properties.Select(x => new 
             {
             Value = x.GetValue(obj, null) == null
                         ?  string.empty
                         :
                         x.PropertyType.BaseType == typeof(Enum)
                         ? Convert.ToInt32(x.GetValue(obj, null)).ToString()
                         : (x.GetValue(obj, null)).ToString(),
             ((ReportAttribute)
             Attribute.GetCustomAttribute(x, typeof(ReportAttribute), false)).Order
             })
             .OrderBy(x => x.Order)
             .Select(x => x.Value.ToString())
             .ToList();

             allValues.AddRange(values);
    }

    return allValues;
}

And in the code I published here I even removed the check for the DisplayDate property in the ReportAttribute, which verifies if the datetime property of the attribute would be displayed as date or datetime…

serenity now!

Answer 1

I would simply extract this into 2 methods, and get rid of the ternary operator:

    // not sure how to name 'obj' and 'x' without more context
    private static object GetValue(PropertyInfo obj, PropertyInfo x)
    {
        if (x.GetValue(obj, null) == null) return string.Empty;

        if (x.PropertyType.BaseType == typeof (Enum))
            return Convert.ToInt32(x.GetValue(obj, null));

        return x.GetValue(obj, null);
    }

    private static int GetOrder(PropertyInfo x)
    {
        return ((ReportAttribute) Attribute.GetCustomAttribute(x, typeof(ReportAttribute), false)).Order;
    }

So you can write:

    public IEnumerable<string> GetValues(List<PropertyInfo> objects)
    {
        var allValues = new List<string>();
        foreach (var obj in objects)
        {
            // Get the PropertyInfo for the obj 
            var properties = GetPropertiesWithTheAttributes(obj);
            var values = properties.Select(x => new
                                                    {
                                                        Value = GetValue(obj, x),
                                                        Order = GetOrder(x)
                                                    })
                .OrderBy(x => x.Order)
                .Select(x => x.Value.ToString())
                .ToList();

            allValues.AddRange(values);
        }

        return allValues;
    }

If you really want to inline this, you can change the lambda expression in your Select to a statement:

.Select(x =>
            {
                object value;
                if (x.GetValue(obj, null) == null) value = string.Empty;
                else if (x.PropertyType.BaseType == typeof (Enum))
                    value = Convert.ToInt32(x.GetValue(obj, null));
                else value = x.GetValue(obj, null);

                return new
                            {
                                Value = value,
                                ((ReportAttribute)
                                Attribute.GetCustomAttribute(x, typeof (ReportAttribute), false)).
                                    Order
                            };
            })