I have 2 buttons on form1 to open 2 other forms: form2.show() and form3. show().

---

Achievement provides the ultimate pleasure in life

Check the Application.OpenForms collection.

---

Coding Light - Illuminated Ideas and Algorithms in Software
Coding Light Wiki �LinkedIn �ForumsBrowser

Check the Application.OpenForms collection.

---

Coding Light - Illuminated Ideas and Algorithms in Software
Coding Light Wiki �LinkedIn �ForumsBrowser

Your main form should be the "switchboard", keeping track of form lifetimes. First Form3, it should declare an event:

public partial class Form3 : Form {
public EventHandler RequestForm2;
public Form3() {
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e) {
RequestForm2(this, EventArgs.Empty);
}
}

Now the main form:

public partial class Form1 : Form {
public Form1() {
InitializeComponent();
}

Form2 mForm2;

private void showForm2() {
if (mForm2 == null) {
mForm2 = new Form2();
mForm2.FormClosed += mForm2_FormClosed;
mForm2.Show();
}
else {
mForm2.WindowState = FormWindowState.Normal;
mForm2.Focus();
}
}

void mForm2_FormClosed(object sender, FormClosedEventArgs e) {
mForm2 = null;
}

private void button1_Click(object sender, EventArgs e) {
showForm2();
}

private void button2_Click(object sender, EventArgs e) {
Form3 frm = new Form3();
frm.RequestForm2 += Form3_RequestForm2;
frm.Show();
}

private void Form3_RequestForm2(object sender, EventArgs e) {
showForm2();
}
}

---

Hans Passant.