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c#genericsabstract-class
Richard
Richard

Reputation: 588

Generic Type Constraint where class implements an abstract class

I have an Generic Abstract Class with some properties like Id, Name, Status, this class inherits several catalogs. My question is whether it is possible to create a method with a restriction for the catalogs that implement the Abstract Class.

I give some examples so that they understand what I want to do:

public abstract class AbsCatalog<T>
{
    public T Id { get; set; }
    public string Name { get; set; }
    public bool Status { get; set; }
}

These are the classes that implement the abstract class

public class Agent : AbsCatalog<string>
{
    public string Office { get; set; }
    public Estado Estado { get; set; }
}

public class Models : AbsCatalog<int>
{
    public int Year { get; set; }
    public string Description { get; set; }
}

The method I want to implement is the following:

List<Agent> Agents = service.GetAgents();
string AgentsDescription = GetDescription<Agent>(Agents);

List<Model> Models = service.GetModels();
string ModelsDescription = GetDescription<Model>(Models);

private string GetDescription<T>(List<T> list) where T : AbsCatalog<T>
{
    string description = string.Empty;

    if (list.Exists(x => x.Id.ToString() == "0"))
        description = "";
    else
        description = string.Join(", ", list.Where(x => x.Status).Select(x => x.Name).ToArray());

    return description;
}

Upvotes: 1

Views: 309

Answers (1)

DavidG
DavidG

Reputation: 118937

I think the only way is to use two generic type parameters here, for example:

private string GetDescription<T, U>(List<T> list) where T : AbsCatalog<U>
{
    //snip   
}

And then call it like this:

string AgentsDescription = GetDescription<Agent, string>(Agents);

Upvotes: 4

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