Provide Default behaviour of "Nullable" types in plain objects when value is NULL

[garzy]

Hello!, I'm currently generating javascript files with a template, injecting the values with morestachio.

The Problem

Part of my template file (javascript.tpl):

 var loginBonusAmount = {{LoginBonusAmount}};

Part of my plain object (JavascriptParams.cs):

public int? LoginBonusAmount { get; set; }

Wanted output if property is NULL:

var loginBonusAmount = null;

Current output:

var loginBonusAmount = ;

The Solution

public class NullableValuesResolver : IValueResolver {
        public bool CanResolve(Type type, object value, string path, ContextObject context) {
            var propertyType = type.GetProperty(path).PropertyType;
            return Nullable.GetUnderlyingType(propertyType) != null;
        }

        public object Resolve(Type type, object value, string path, ContextObject context) {
            var result = type.GetProperty(path).GetValue(value);
            if (result == null)
            {
                return "null";
            }
            return result;
        }
    }

[...]

 var options = new ParserOptions(sourceTemplate)
 {
    ValueResolver = new NullableValuesResolver()
 };

[garzy]

Additionally, Null properties of Parser options doesn't works for me in String Properties of my plain .cs object.

Non Working Code 👎

var options = new ParserOptions(sourceTemplate)
 {
    ValueResolver = new NullableValuesResolver(),
     Null = "null" //doesn't works :(
 };

I've fixed this problem using always my NullableValuesResolver, as this:

Working Code 👍

public class NullableValuesResolver : IValueResolver {
        public bool CanResolve(Type type, object value, string path, ContextObject context) {
           return true;
        }

        public object Resolve(Type type, object value, string path, ContextObject context) {
            var result = type.GetProperty(path).GetValue(value);
            if (result == null)
            {
                return "null";
            }
            return result;
        }
    }

[JPVenson]

@garzy Thank you for this pretty good written bug i appreciate that. I was able to reproduce the bug and fixed it. A Nuget Release is on its way and should be available soon.

https://www.nuget.org/packages/Morestachio/2.3.7

You should be able to use the "Null" property of the Options object again.

[garzy]

Thanks for the very fast bugfix, I've tested the new version this morning and its works like a charm with only this code:

var options = new ParserOptions(sourceTemplate)
            {
                Null = "null"
            };

I don't need my NullableValuesResolver anymore :)

Thanks!

[JPVenson]

You are welcome.

That are the perks of an HomeOffice ;-)