Calling a combobox from another form

I have a combobox on form1 that I need to call on form2 to get the user selection. Can some one please give me an example on how to do this?

EDIT: Forgot to explain what Im trying to do. I have a readonly textbox....a user clicks edit to edit the text but I want the text they want/chose to edit to pop up right when form2 is called.

I have this code on form1

    public string SelectedComboValue
     {
         get { return comboBox1.SelectedItem.ToString(); }
     }
 

And this code on form 2

    EDIT: Added Form1 form1 = null; BUT its still not returning the SelectedComboValue
     public Form2(Form1 parentForm1) : this()
     {
          form1 = parentForm1;
     }
 

But it gave me an error saying that form1 is not in this context

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