It sounds like you doing something like this:
public class MyForm : Form
{
public void foo()
{
Data = "balbla";
}
public string Data;
}
public void bar()
{
MyForm form1 = new MyForm();
form1.foo();
MyForm form2 = new MyForm();
Console.WriteLine(form2.Data);
}
and your getting null.
in which case you should make Data static:
public static string Data;
now you will get "blabla".