Deserialize JSON to C# object to display nested array as string in grid

Question

Everything run and Deserialize OK. Except the Roles is show up as System.Collections.Generic.List`1[System.String]

Problem

If I want to attach each field to a grid. Is there a way to show the collection as a string without looping through the Roles property?

JSON

[{
    "Name":"test",
    "Email": "[email protected]",
    "Roles": ["Admin","User","Guest"],
    "Age":"23"
},
{
  "Name":"test1",
  "Email": "[email protected]",
  "Roles": ["Admin", "User" ,"Guest"],
  "Age":"33"
}]

Model

public class example
{
    public string Name { get; set; }
    public string Email { get; set; }
    public IList<string> Roles { get; set; }
    public string Age { get; set; }
}

Deserialization

List<Exampe> list = JsonConvert.DeserializeObject<List<Exampe>>(bundle);

You need to clarify what the actual problem is because everything shown above should work as expected. Roles will be deserialized to a list of strings by default based on the type shown for the property. — Nkosi
– Nkosi, Commented Jul 26, 2018 at 21:09
In future note that question like this appears to be an XY problem. Remember that providing a minimal reproducible example should help clarify the actual problem most of the time. — Nkosi
– Nkosi, Commented Jul 26, 2018 at 21:20
I'm using Windows Form, DataGridView. Thank you, Nkosi. Next time, I will be more accurate with question and format. — zAnthony
– zAnthony, Commented Jul 26, 2018 at 21:24
Show how you assign the data to the data grid after deseiralization.. — Nkosi
– Nkosi, Commented Jul 26, 2018 at 21:42

Xiaoy312 · Accepted Answer · 2018-07-27 19:38:19Z

2

As @Nkosi mentioned, this is a XY problem. The problem is not deserialization, but rather how DataGridView handles a "complex" property type.

You can add a new property to display it:

Either by directly modifying the class definition:

public class Example
{
    public string Name { get; set; }
    public string Email { get; set; }
    public string[] Roles { get; set; }
    public string Age { get; set; }

    public string RolesText => string.Join(", ", Roles ?? Array.Empty<string>());
}

Or by altering the DataSource of the DataGridView:

dgv.DataSource = list.Select(x => new
{
    x.Name, x.Email, x.Age,
    Roles = string.Join(", ", x.Roles ?? Array.Empty<string>()),
}).ToList();

--

Bonus: Here is an generator for the 2nd approach:

string GenerateModelFormatter<T>()
{
    return new StringBuilder()
        .AppendLine("x => new")
        .AppendLine("{")
        .AppendLine(string.Join(",\n", typeof(T).GetProperties()
            .Select(x => x.PropertyType != typeof(string[])
                ? $"\t{x.Name} = x.{x.Name}"
                : $"\t{x.Name} = string.Join(\", \", x.{x.Name} ?? Array.Empty<string>())")))
        .AppendLine("}")
        .ToString();
}

edited Jul 27, 2018 at 19:38

answered Jul 26, 2018 at 22:02

Xiaoy312

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4 Comments

Nkosi Over a year ago

I personally prefer the second option. clean and simple.

zAnthony Over a year ago

Thank you all for the help. I was afraid of having to do something like this because I'm dealing with a class that has over 300+ properties and 50% of them will be an array of string[]. Big decision now..

Xiaoy312 Over a year ago

You can use reflection or meta-programming to generate the lambda function:

zAnthony Over a year ago

That is a little bit out of my scope of knowledge but if you can point me in the right direction, i'm willing to learn.

Danny_ds · Accepted Answer · 2018-07-26 20:52:49Z

1

You have Name twice in your class - you probably want:

public class example
{
    public string Name { get; set; }
    public string Email { get; set; }
    public IList<string> Roles { get; set; }
    public string Age { get; set; }
}

answered Jul 26, 2018 at 20:52

Danny_ds

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Comments

D-Shih · Accepted Answer · 2018-07-26 21:13:43Z

1

If I understand correctly you seem to want to get string[] instead of List<string>

Roles can be string[]

public class Example
{
    public string Name { get; set; }
    public string Email { get; set; }
    public string[] Roles { get; set; }
    public string Age { get; set; }
}

answered Jul 26, 2018 at 21:13

D-Shih

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