Generic List created at runtime
i neeed something like this in C#.开发者_如何学Python. have list in class but decide what will be in list during runtime
class A
{
List<?> data;
Type typeOfDataInList;
}
public void FillData<DataTyp>(DataTyp[] data) where DataTyp : struct
{
A a = new A();
A.vListuBudouDataTypu = typeof(DataTyp);
A.data = new List<A.typeOfDataInList>();
A.AddRange(data);
}
Is this possible to do something like this ?
class A<T>
{
public readonly List<T> Data = new List<T>();
public Type TypeOfDataInList { get; private set; }
public A()
{
TypeOfDataInList = typeof(T);
}
public void Fill(params T[] items)
{
data.AddRange(items);
}
}
If you don't know the type or have multiple objects of different types, declare an instance of A like this:
A<object> myClass = new A<object>();
myClass.Fill(new object(), new object());
Otherwise if you know the type, you can do this:
A<int> myInts = new A<int>();
myInts.Fill(1, 2, 5, 7);
Yes.
class A
{
IList data;
Type typeOfDataInList;
}
public void FillData<T>(T[] data) where T : struct
{
A a = new A();
A.typeOfDataInList = typeof(T);
A.data = new List<T>(data);
}
It would be better to make the A
class generic:
class A<T>
{
IList<T> data;
Type typeOfDataInList;
}
public void FillData<T>(T[] data) where T : struct
{
A<T> a = new A<T>();
a.typeOfDataInList = typeof(T);
a.data = new List<T>(data);
}
You are going to need to use reflection to instantiate an IList<
T>
where T is not known until runtime.
See the following MSDN article, which explains it better than I could (scroll down to the section on how to construct a generic type): http://msdn.microsoft.com/en-us/library/b8ytshk6.aspx
Here is a short example:
Type listType = typeof(List<>);
Type runtimeType = typeof(string); // just for this example
// assert that runtTimeType is something you're expecting
Type[] typeArgs = { runtimeType };
Type listTypeGenericRuntime = listType.MakeGenericType(typeArgs);
IEnumerable o = Activator.CreateInstance(listTypeGenericRuntime) as IEnumerable;
// loop through o, etc..
You might want to consider a generic class:
public class A<T> where T : struct
{
public List<T> data;
public Type type;
}
public void FillData<DataType>(DataType[] data) where DataType : struct
{
A<DataType> a = new A<DataType>();
a.data = new List<DataType>();
a.AddRange(data);
}
System.Collections.Generic.List<T>
?
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