How to populate values of some controls in a form which is associated another form in realtime?

Question

My aim each time when I click on button1 then only one instance of Form2 exist with updated string or else if I design with other controls in Form1 and Form2.
Below example success for the first time by clicking button1, any other times it does not work (updated) that textBox1.Text to Form2's label.text.
How can I handle this?
public partial class Form1 : Form
public Form1()
InitializeComponent();
private bool CheckOpened(string name)
FormCollection fc = Application.OpenForms;
foreach (Form frm in fc)
if (frm.Text == name)
return true;
return false;
private void button1_Click(object sender, EventArgs e)
Form2 frm2 = new Form2(textBox1.Text);
if (!CheckOpened("Form2"))
frm2.Show();
else
frm2.label1.Text = textBox1.Text;
public partial class Form2 : Form
public Form2(string str)
InitializeComponent();
label1.Text = str;

Answer 1

You should first check if the Form is open, then only create a new instance if it's not open. Based on your code, I'd redesign CheckOpened so that it returns the opened instance, or null if it's not open. In button1_click, check the return value. If it's
null, create a new instance, otherwise use the returned refernce to make the modification, either by directly accessing label1, or indirectly by adding a property to Form2 that changes label1.text in the property-set method.
However, instead of searching for an open form, I'd just store a reference to it in a class level variable when it's created. So you just check for null if it's open. Additionally you must set it to null when handling Form2's FormClosed event.
Armin