I've never used C#, but this is based on my java knowledge. I can't see it being possible just you've done that. But, if every MyObject object is going to need to call a method in 'its' Form1, why not give your MyObject a reference to its Form1.
code:
public partial class Form1 : Form
{
MyObject o;
public Form1()
{
this.o = new MyObject(this);
//Constructor Body
}
public void method()
{
//Method Body
}
}
class MyObject
{
Form1 myform;
//Constructor, takes Form1 object, assigns to myForm vairable
myForm.method(); //Not any Form1 but the "parent" Form1 class.
}
I think that's what you're looking for - let me know if it works for you like you wanted.