Dynamically pass Type to Method<T> - linq

Question

I've a method , that retrieves to me some data according to some type I passed in parameter, like this :
protected void FillList<TEntity>()
{
doWorkForTEntity();
}
I Need to dynamically call this method :
Type[] entities = System.Reflection.Assembly.GetAssembly(typeof(User)).GetTypes();
Type currentEntity = (from entity in entities
where entity.Name.Equals(this.targetEntity)
select entity).FirstOrDefault();
FillList<currentEntity>();
I got this error :
The type or namespace name 'currentEntity' could not be found (are you missing a using directive or an assembly reference?)
I've tried an intermediate object type, no success
Any Idea please ?

Answer 1

Since there is no information about entity type in compile time, you need to construct and call appropriate method by reflection:
Type[] entities = System.Reflection.Assembly.GetAssembly(typeof(User)).GetTypes();
Type currentEntity = (from entity in entities
where entity.Name.Equals(this.targetEntity)
select entity).FirstOrDefault();
var method = this.GetType().GetMethod("FillList", BindingFlags.Instance | BindingFlags.NonPublic)
.MakeGenericMethod(currentEntity);
method.Invoke(this, new object[0]);

Answer 2

You need to do that with reflection as well, so it won't fail in compile time (compiler checks):
Generic class:
Type[] entities = System.Reflection.Assembly.GetAssembly(typeof(User)).GetTypes();
Type currentEntity = (from entity in entities
where entity.Name.Equals(this.targetEntity)
select entity).FirstOrDefault();
Type fillListType= typeof(FillList<>);
Type constructedGenericClass = fillListType.MakeGenericType(currentEntity);
object myList = Activator.CreateInstance(constructedGenericClass );
Generic Method:
Type[] entities = System.Reflection.Assembly.GetAssembly(typeof(User)).GetTypes();
Type currentEntity = (from entity in entities
where entity.Name.Equals(this.targetEntity)
select entity).FirstOrDefault();
MethodInfo methodinfo = this.GetType().GetMethod("FillList");
MethodInfo genericMethod = method.MakeGenericMethod(currentEntity);
genericMethod.Invoke(this, null);

Answer 3

Type parameters must be specified at compile time and can´t be assigned at runtime like in your example. You get the error message because there´s no Type called currentEntiry since it´s just a variable.

Answer 4

Change your method to take an instance of the Type TEntity:
protected void FillList<TEntity>(TEntity instance)
{
doWorkForTEntity();
}
Create a dynamic instance from the Type name and then call the modified method:
dynamic instance = Activator.CreateInstance(this.targetEntity);
FillList(instance);
The dynamic type is basically doing what the other answers have shown you - but IMHO this code is neater and clearer in its intent.