[DotNetDevelopment] write to a form textbox from static method

[Dickery1]

i have issues in writing to a textbox from static method
        private  static void appendToTextBox(string str){
            Form1.textBox1.Text  += str + "\r\n";

        }

        An object reference is required for the nonstatic field, method, or
property 'collectTickData.Form1.textBox1'

how do i fix it. aparrently all the mehods calling appendToTextBox are
static and so i made it static too.
appreciate any help.