Dynamic JsonIgnore for properties within a list

Question

I am using the JSON.Net library. I have some JSON which looks like this:

"Templates": [
    {
        "Name": "Default Fields 1",
        "Fields": [16, 10, 0, 4, 5, 11, 12, 7, 15, 17, 9, 25, 3],
        "Formats": [
            "string", "datetime", "LeftZeroPaddedString13", "2dp", "2dp", "2dp", "2dp", "int", "int",
            "string", "int", "int", "int", "int"
        ]
    },
    {
        "Name": "Default Fields 2",
        "Fields": [3, 25, 9, 17, 15, 7, 12, 11, 5, 4, 0, 10, 16],
        "Formats": [
            "int", "int", "int", "int", "string", "int", "int", "2dp", "2dp", "2dp", "2dp", "LeftZeroPaddedString13",
            "datetime", "string"
        ]
    }]

And I am deserializing it to the Templates property within the following class:

public class Options
{
    public List<FieldTemplate> Templates { get; set; }
}
public class FieldTemplate
{
    public string Name { get; set; }
    public List<int> Fields { get; set; }
    public List<string> Formats { get; set; }
}

This works fine, but under some circumstances (not always) I want to prevent the Fields and Formats properties from being included when I serialize the object again (though I do want to keep the Name property in the serialized output). I have thought about using ShouldSerializeFields() and ShouldSerializeFormats() within FieldTemplate and then looping through the object to set a boolean property which each of these methods can read, but it doesn't seem elegant. Is there a better way? For example, I could set boolean properties in Options which FieldTemplate could then use. I don't know how to do that though, or even if its possible.

You can use a custom contract resolver to do this. See Andrew Whitaker's answer in [Dynamic json serialization filtering via reflection](http://stackoverflow.com/q/28606326/10263); looks like that should work for your needs. — Brian Rogers, Jun 09 '16 at 22:44
Thanks @BrianRogers. In the end I took Vitaliy's advice and used a static class as this suits my needs better. I'll post an answer for this. — mulllhausen, Jun 10 '16 at 04:27

score 0 · Answer 1 · answered Jun 10 '16 at 04:32

In the end I used a static class with a switch for each property i wanted to dynamically show/hide:

public class FieldTemplate_JSONSerialization_Switches
{
    public static bool Fields = true;
    public static bool Formats = true;
}

public class Options
{
    public List<FieldTemplate> Templates { get; set; }
}

public class FieldTemplate
{
    public string Name { get; set; }
    public List<int> Fields { get; set; }
    public List<string> Formats { get; set; }

    // instructions to Json.NET
    public bool ShouldSerializeFields()
    {
        return FieldTemplate_JSONSerialization_Switches.Fields;
    }

    public bool ShouldSerializeFormats()
    {
        return FieldTemplate_JSONSerialization_Switches.Formats;
    }
}

Then from elsewhere I can enable/disable these properties:

if (condition)
{
    FieldTemplate_JSONSerialization_Switches.Fields = true;
    FieldTemplate_JSONSerialization_Switches.Formats = false;
}
else
{
    FieldTemplate_JSONSerialization_Switches.Fields = false;
    FieldTemplate_JSONSerialization_Switches.Formats = true;
}

score -1 · Answer 2 · edited May 23 '17 at 11:52

-1

Here is similar question and answer.

Json.Net documentation about ConditionalProperties

Edit To not iterate over collection create static object and check it's properties inside ShouldSerializeXYZ().

edited May 23 '17 at 11:52

Community

1
1

answered Jun 09 '16 at 06:47

Vitaliy Smolyakov

452
3
7

That's just the `ShouldSerializeXYZ()` that I mentioned in my question. The problem I am having is more about how to conditionally trigger `ShouldSerializeXYZ()` when its within an object in a list. – mulllhausen Jun 09 '16 at 07:03
1

Ok, my mistake. Then create static object and check it's properties inside ShouldSerializeXYZ() :) – Vitaliy Smolyakov Jun 09 '16 at 07:18

Dynamic JsonIgnore for properties within a list

2 Answers2