Instantiating an object whose type is not known until runtime?

[keyser456]

public void AddItem()
{
this.Add(new ***); // here is where I'm stumped
}

private void Add(MySubItemType inSubItem)
{
this.Controls.Add(inSubItem);
}

There needs to be a type where the *** is but this type will not be known until runtime. Obviously, it will derive from MySubItem. Is there any way to do this other than passing in an instance of the unknown item type at runtime and somehow parsing the layout, then modifying the MySubItem on the fly? Something to the effect of:

this.Add(new typeof(SpecialSubItemType));

where SpecialSubItemType derives from MySubItemType

I know this doesn't work, but maybe it will help explain what I'm trying to do.

 

[snowmaster]

Hi,

I think what you're trying to do is instantiate various objects depending on the situation.

One way is to instantiate the object before you enter the AddItem method and pass it as an argument:

MySpecialObject obj = new MySpecialObject();

anobject.AddItem(obj);

...

public class AnObject
{

  public void AddItem(object obj)
  {
     if (obj is MySubItemType)
       this.Add(obj);
  }

  private void Add(MySubItemType inSubItem)
  {
      this.Controls.Add(inSubItem);
  }

Otherwise I fear you will have to wait until generics appear in .NET Framework 2.0.

Good Luck.

 

[keyser456]

Thanks, but I think I found my answer. There is an activator class that allows you to create an instance of a type that you may not know until runtime.

MDSubformItem tempitem = (MDSubformItem)Activator.CreateInstance(this.subformitemType);

subformItemType is of System.Type and will be handed in after the program starts

 

[SonicChen]

faint -.-;;
i haven't catched the question for my poor eng.....

way to gold shines more than gold

 

[chiph]

keyser456 wants to do a late-binding call. The System.Activator is how you do it.

Chip H.


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