How do I pass data from child of child form to parent form?

Question

I am new to c#. I have the following in my project in windows forms:

Form1 with button and DataGridView.

Form2 with button.

Form3 with button and 3 textBoxes.

In form1, I click buttonOpenForm2 form2 pops up. Then in form2 I click buttonOpenForm3 form3 pops up which has 3 text boxes and button. Now the 3 forms are open.

now in form3, I enter values in textBox1, textBox2 and textBox3 and when click buttonAddRow ( from form3) I want these values to be inserted into the DataGRidView in Form1.

My question is: How can I add a row into DataGridView in Form1 ( parent) from form3 (child of child form) WITHOUT closing form2 and form3? I mean I want to pass the data while form2 and form3 are still open.

Please help me. Thank you

 

 

 

Form1:   public partial class Form1 : Form

 {      

  public Form1()     

{         InitializeComponent();       

}      

 private void buttonOpenForm2 _Click(object sender, EventArgs e)     

{         

Form2 frm2 = new Form2();         

frm2.Show();     

}   

}    

Form2:   

public partial class Form2 : Form 

{     

public Form2()     

{         

InitializeComponent();     

}      

 private void buttonOpenForm3 _Click(object sender, EventArgs e)     

{         

Form3 frm3 = new Form3();         

frm3.Show();     

} 

}      

Form3:     

public partial class Form3 : Form   

{     

public Form3()     

{        

 InitializeComponent();     

}      

 private void buttonAddRow _Click(object sender, EventArgs e)     

{         //What to write here to insert the 3 textboxes values into DataGridView?     

 }

 }