Problem with List textbox

Hi everybody.

I have got a textbox called "textbox1". And an object, called player[0]
There I generated a list: public List textboxInformation = new List();

In the main method i wrote:
player[0].textboxInformation .Add(textbox1);

I want to access this box, by calling the "object.textboxInformation"

If i count "player[0].textboxInformation.Count" , i get "1" as a result.
So it has to be stored.

But i can´t access it by:
MessageBox.Show(player[0].textboxInformation [0].Text);
And I also can´t modify the text:
spieler[0].textboxInformation [0].Text = "TEST";

It always says, its no object...

Does anyone know, who to access it correctly?


Thx alot!