CODEWITHSUNDEEP
c#entity-framework
al.koval
al.koval

Reputation: 2542

Data in the model field is not updated

In the table column (of type nvarchar) I store an array of string values (List <string>). To get a data model I use Entity Framework.

Model:

namespace Project.Models.Atm
{
    public class MyObject
    {
        [JsonIgnore]
        public string _Parameters { get; set; }

        [NotMapped]
        [JsonProperty("parameters")]
        public List<string> Parameters
        {
            get
            {
                return JsonConvert.DeserializeObject<List<string>>(string.IsNullOrEmpty(_Parameters) ? "" : _Parameters);
            }
            set
            {
                _Parameters = JsonConvert.SerializeObject(value);
            }
        }
    }
}

If a new list of string values is assigned to the field of the myObject.parameters object, then I will do everything well.

MyObject myObject = new MyObject();
List<string> parameters = new List<string>();

parameters.Add("value");
myObject.parameters = parameters;

But if you try to add a value to the list of objects one by one, they are not added. 

MyObject myObject = new MyObject();

myObject.parameters.Add("value"); <-- The value will not be added and there will be no errors.

What could be the problem?

Upvotes: 1

Views: 32

Answers (1)

Rafal
Rafal

Reputation: 12619

While executing:

myObject.parameters.Add("value");

you call:

get
{
    return JsonConvert.DeserializeObject<List<string>>(string.IsNullOrEmpty(_Parameters) ? "" : _Parameters);
}

and this code is creating new list for you and you are adding to it not to the string that is actually stored in the database.

To avoid temptation of adding to this list change your property to return IEnumerable<string> instead and always assign new list to the property.

Upvotes: 1

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