add property and value to existing class c#

Question

I have a requirement to add a property in existing class as per user configuration, I mean if the user has been configured in the database to add a new property like property Name is 'Name', the datatype is 'string' and value is 'Mishra'. After achieving this, I will save a list of TestClass data in Redis cache.

  class TestClass
    {
        public long ID { get; set; }
    }

I have tried from the link https://msdn.microsoft.com/en-us/library/2sd82fz7.aspx but I want to add an existing class, so can anyone please help me to achieve the same.

I want to render JSON data as per user property (column) configuration for my devex grid.

Data Like-

{
"testClass": [
    {
      "scheduledTime": "2018-07-30T15:30:00",
      "estimatedTime": "2018-07-30T15:30:00",
      "flightNumber": "EY4512",
      "airLine": "assets/images/EY_88x45.jpg",
      "fromVia": "Chengdu,Dallas",
      "partner": "EY2356",
      "status": "Departed",
      "flightColor": null,
      "cityColor": null,
      "publicArrivalPlaceholder1": "CTU,DFW",
      "publicArrivalPlaceholder2": "12_IT",
      "publicArrivalPlaceholder3": "AIR",
      "publicArrivalPlaceholder4": "7/30/2018 3:30:00 PM",
      "publicArrivalPlaceholder5": "7/30/2018 3:30:00 PM",
      "id": "179490",
      "cellRule": "",
      "rowRule": ""
    },
    {
      "scheduledTime": "2018-07-30T17:00:00",
      "estimatedTime": "2018-07-30T14:00:00",
      "flightNumber": "EY1213",
      "airLine": "assets/images/EY_88x45.jpg",
      "fromVia": "Adelaide,Ahmedabad",
      "partner": "EY8562",
      "status": "Departed",
      "flightColor": null,
      "cityColor": null,
      "publicArrivalPlaceholder1": "ADE,AMD",
      "publicArrivalPlaceholder2": "2A_T4",
      "publicArrivalPlaceholder3": "AIR",
      "publicArrivalPlaceholder4": "7/30/2018 5:00:00 PM",
      "publicArrivalPlaceholder5": "7/30/2018 2:00:00 PM",
      "id": "179489",
      "cellRule": "",
      "rowRule": ""
    }]
}

Here scheduledTime, estimatedTime, flightNumber etc are property that i need to resolve at run-time.

Do you want to add the property at runtime or at compile time? — nvoigt, Jul 30 '18 at 10:03
What is your main purpose, are you sure a Dictionary will not be enough, or may be dynamic property ? — nzrytmn, Jul 30 '18 at 10:11
Is there a reason not to use an array with name/value pairs? Or a dictionary? Or even just have the properties default at null and only add that bit of data to the cache if it's not null? You could also just subclass and use a function that determines which type of object to create based on given values. — IAmJersh, Jul 30 '18 at 10:22
I wan to add property at runtime. my main purpose is render a list type json data for my devex grid. I will get that data from a xml to mapped property from user. — radhey_mishra, Jul 30 '18 at 10:40
[How to ignore json fields conditionally](https://stackoverflow.com/questions/34304738/how-to-ignoring-fields-and-properties-conditionally-during-serialization-using-j) — Lucas, Jul 30 '18 at 10:58
How about create the same json pattern dynamically as string and then convert to json with something like this JObject json = JObject.Parse(str); ? you can find more info at https://www.newtonsoft.com/json/help/html/T_Newtonsoft_Json_Linq_JObject.htm — nzrytmn, Jul 30 '18 at 15:05
I also think this is best way to achieve the same in my case. — radhey_mishra, Jul 31 '18 at 01:33

Chayim Friedman · Accepted Answer · 2021-01-27T02:43:24.390

Basically, you cannot change the class definition in C#. But there are some solutions:

Use a custom properties named for example Fields that will be a Dictionary and to add property add it to that dictionary; Or simply instead class use dictionary. Then you when you want to get class properties you just need to iterate over that dictionary.
Create a class in runtime and compile it dynamically; This option is more complex, and you may prefer another options - but it enabled. For more information how to compile class dynamically, see this question. Then you can get a Type object of the class and iterate over its properties (There is the place of TypeBuilder.DefineProperty(); It define a new property to class that created in runtime).
Basically this option is like option 1, but if you're using C# 4+, you can use the keyword dynamic, that can be used for accessing dictionary like an object; For example, create the following class:

dynamic dict = new System.Dynamic.ExpandoObject();
dict.Property = "Value";
dict.Num = 123;
Console.WriteLine(dict.Property);
Console.WriteLine(dict.NonExistProperty); // Will throw an exception

For more information about dynamic object in C#, see Microsoft Docs.

Edit:

Note that dynamic objects handled by DLR (Dynamic Language Runtime) and not by CLR (Common Language Runtime), and so code that use them is less effecient.

add property and value to existing class c#

1 Answers1

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