Question

I have wanted to navigate through forms so when I client the buttonKlient I go to the Form2 then when I click control ‘x’ I go back to Form1 I got:

(the fk is Form2)

   private void button1_Click(object sender, EventArgs e) {
                if (fk == null)
                    fk = new OknoKlient();
                fk.Tag = this;
                fk.Show(this);//here is ObjectDisposedException
                Hide();
            }

Then in Form2

 protected override void OnFormClosing(FormClosingEventArgs e) {
            if (e.CloseReason == CloseReason.WindowsShutDown) return;
            var form1 = (Form1)Tag;
            form1.Show();
            Hide();
            // DO WHATEVER HERE
        }

When I click button1 the Form2 fk opens, then I close it by x control then click the button1 again and I get the exception ObjectDisposedException.

Answer 1

protected override void OnFormClosing(FormClosingEventArgs e) {
    if (e.CloseReason == CloseReason.WindowsShutDown) return;
    e.Cancel = true; // <---------------------- this
    var form1 = (Form1)Tag;
    form1.Show();
    Hide();
    // DO WHATEVER HERE
}

You’re hiding the form yes.. but the form is still being disposed. You need to add e.Cancel = true; to cancel the form closing.