Child MDI force Parent MDI to open new child.

I have a parent Form named Form1, and 2 child forms called Child1 and Child2. In the parent form you need to do something like the following.
public partial class Form1 : Form
{
public Form initForm = new Child1();
public Form nextChildForm = new Child2();
private void Form1_Load(object sender, EventArgs e)
{
initForm.MdiParent = this;
initForm.Show();
nextChildForm.MdiParent = this;
}
}
 
In the Child1 form, i have a button to display the other child form, here is the code to perform that.
private void button1_Click(object sender, EventArgs e)
{
Form1 parent = (Form1)this.MdiParent;   // Form1 needs to be the name of the parent form
parent.nextChildForm.Show();               // can perform on public items
}