Is possible to cast object type to another type inline in C#?-CodePudding

I have a program in .Net 5 C# that make a HTTP Request and the content (JSON) is deserialized (JsonNewtonsoft) in specific type:

// Class definition
public class FooSerializerModel {

    [JsonProperty("latitude")] 
    public string Latitude { get; set; }

    [JsonProperty("longitude")]
    public string Longitude { get; set; }

}

// Deserialization
var fooJson = JsonConvert.DeserializeObject<FooSerializerModel>(response);

It works fine, now, I need cast the fooJson variable type to other type for pass it to Data Layer Method:

public class DataModel {

    public string Latitude { get; set; }

    public string Longitude { get; set; }

}

I need something like this:

var data = fromJson as DataModel;

But I get this error: Cannot convert type FooSerializerModel to DataModel Why?

I know is possible solve this problem using:

var data = new DataModel() {
    Latitude = fromJson.Latitude,
    Longitude = fromJson.Longitude
}

But if my class has 50 attributes I would have to assign one by one, it would be more lines of code and I could forget some of them when doing it explicitly.

Is it possible to do an implicit assignment on a single line? I have tried this:

var data = fromJson as DataModel; // Error

var data = (DataModel) fromJson; // Error

var data = (DataModel) (object) fromJson; // Exception 'Unable to cast object of type' when use 'dotnet run'

I remember that it is possible to do this in TypeScript if you work with types with interfaces and is easy!

CodePudding user response：

All the code was tested in Visual Studio and working properly.

var fooJson = JsonConvert.DeserializeObject<DataModel>(response);

everything will be fine, since you don't really need [JsonProperty] attribute. You just need to fix your startup or there are another options to conver low case to upper.

public void ConfigureServices(IServiceCollection services)
{
services.AddControllersWithViews()
    .AddNewtonsoftJson(options =>
           options.SerializerSettings.ContractResolver =
              new CamelCasePropertyNamesContractResolver());

     .... other code
}

but I even don't think that json attributes will affect your classes even if you use them for MongoDB. Classes are classes, but attributes are attributes, they live a completely separate life.

But if you like it hard way I can offer this

public class DataModel 
{

    public virtual string Latitude { get; set; }

    public virtual string Longitude { get; set; }

}

public class FooSerializerModel:DataModel
{

    [JsonProperty("latitude")]
    public override string Latitude { get; set; }

    [JsonProperty("longitude")]
    public override string Longitude { get; set; }

}

Now you can write the code you wanted

var fooJson = JsonConvert.DeserializeObject<FooSerializerModel>(response);
DataModel data=fooJson;

CodePudding user response：

Assuming both your API contract and your data-layer contract expose the same properties with the same types and names, you can use an interface:

public interface ICoordinates
{
    public string Latitude { get; set; }
    public string Longitude { get; set; }
}

public class FooSerializerModel : ICoordinates
{

    [JsonProperty("latitude")] 
    public string Latitude { get; set; }

    [JsonProperty("longitude")]
    public string Longitude { get; set; }

}

public class DataModel : ICoordinates
{
    [SampleDbAttribute(ColumnName: "col_latitude")]
    public string Latitude { get; set; }

    [SampleDbAttribute(ColumnName: "col_longitude")]
    public string Longitude { get; set; }
}

Then you can cast between the inherited types because they both implement the same interface:

// Deserialization
var fooJson = JsonConvert.DeserializeObject<FooSerializerModel>(response);

var data = fromJson as DataModel;