CODEWITHSUNDEEP
c#listclassgenericstypes
Chewbye
Chewbye

Reputation: 353

C# generic list as constructor parameter

I am trying to give a list which I don't know the type to a constructor of a class.

First I have a class which contains multiples tables and a method:

public class A{
private List<float> _List1;
private List<Proj> _List2;

...

    public void saveConfig(string path){
        ConfContainer confContainer = new ConfContainer ();
        Type type = this.GetType();
        PropertyInfo[] properties = type.GetProperties();

        confContainer.ConfEntries = new ConfEntry[properties.Length];
        int i = 0;
        foreach (PropertyInfo property in properties){
            if(property.GetValue(this,null) is IList && property.GetValue(this,null).GetType().IsGenericType){
                confContainer.ConfEntries [i] = new ConfEntryList (property.Name, property.GetValue(this, null));
            }
        }
     }
}

And the generic class I am trying to achieve:

public class ConfEntryList<T>: ConfEntry{

    [XmlArray("Valeurs")]
    [XmlArrayItem("Valeur")]
    public List<T> Valeurs;

    public ConfEntryList(){

    }

    public ConfEntryList(string attribut, List<T> valeurs){
        this.Attribut = attribut;
        this.Valeur = null;
        this.Valeurs = valeurs;
    }   
}

The problem is this line: confContainer.ConfEntries [i] = new ConfEntryList (property.Name, property.GetValue(this, null));

I don't know how to pass the List type to the constructor:

new ConfEntryList<T>(...)

Is it possible to pass the type T (of any generic list captured by PropertyInfo) to a generic constructor?

Thanks in advance for any help

Upvotes: 1

Views: 1680

Answers (1)

Richard Friend
Richard Friend

Reputation: 16018

You need to use Activator.CreateInstance

Something like this..

       if(property.GetValue(this,null) is IList 
            && property.GetValue(this,null).GetType().IsGenericType){

            var listType = property.PropertyType.GetGenericArguments()[0];
            var confType = typeof(ConfEntryList<>).MakeGenericType(listType);
            var item = (ConfEntry)Activator.CreateInstance(confType,
                  new object [] {property.Name, property.GetValue(this, null)});
            confContainer.ConfEntries [i] =  item;
       }

Upvotes: 2

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