How to pass combobox value from windows form EdirRow to windows form Form1 where click button

I have two windows form
In form1 i have combobox1 drop down style:drop down list
In Edit Row formI have combobox and button in Edit Row form

Actually i need when click on button 1 on windows form Edit Row
get selected value of combobox1 from windows form Edit Row to windows form Form1

Details

form1_load

var dataSourceAr = new List<Country>();
 dataSourceAr.Add(new Country() { Name = "???? ????", Value = 0 });
 dataSourceAr.Add(new Country() { Name = "??????", Value = 1 });
 dataSourceAr.Add(new Country() { Name = "????????", Value = 2 });
 var dataSourceEn = new List<Country>();
 dataSourceEn.Add(new Country() { Name = "SelectCountry", Value = 0 });
 dataSourceEn.Add(new Country() { Name = "Jordon", Value = 1 });
 dataSourceEn.Add(new Country() { Name = "Emarate ", Value = 2 });
 var combined = dataSourceEn.Join(dataSourceAr, en => en.Value, ar => ar.Value, (en, ar) => new { Value = en.Value, Name = $"{ar.Name} - {en.Name}" }).ToList();
 comboBox1.DataSource = combined;
 comboBox1.DisplayMember = "Name";
 comboBox1.ValueMember = "Value";

public class Country
    {
        public string Name { get; set; }
        public int Value { get; set; }
    }


under button 1 click on windows form Edit Row that i need to pass selected value from it to form1 combobox

private void button1_Click(object sender, EventArgs e)
        {  
                Form1 frm = new Form1();
                var cb1 = frm.comboBox1;
                var index1 = cb1.FindString(comboBox1.Text);
                cb1.Text = index1.ToString();
                frm.Show();
}


Edit Row load form
// same values and code of combobox1 in Form1


when click button value of combobox1 from Edit form will transfere to second form Form1

Result of code above when click button it show form1

but value of combobox1 selected from Edit Row form not select same value to another combox in form1
nothing changed and nothing selected in form1 combobox value

so that how to solve problem ?