How to add a control to a panel on a form from another user control

Question

I have a form1.cs and in that form I have a panel1, in the load event of the form1.cs I am adding a control to the panel1. Now my issue is, I have a control called Numbers.cs, I need to add another control to that panel1 but from this control in a button event. How can I do this?

public partial class Number : UserControl
{
    public Number()
    {
        InitializeComponent();
    }

    private void btnAcceptWelcome_Click(object sender, EventArgs e)
    {
          //HERE I NEED TO PASS A CONTROL TO THE PANEL1 IN FORM1.CS
          //NOT SURE HOW TO DO THIS.
    }
}

MORE INFO

So basically I have a folder called UserControls and in that folder I have

Numbers.cs
Letters.cs
Welcome.cs

All of them user controls, then i have a form

Form1.cs

Form1.cs instantiates Welcome and it is added to a Panel1 on the Form1.cs on form load. Then Welcome.cs has a button, when I click this button I need to swap to Numbers.cs. But I dont know how to do this from Welcome.cs

Answer 1

Another way would be to use a Custom Event raised by Numbers and handled by Form1 to pass the control and add it to your Panel's Control Collection.

---

This is an example of an Custom Event added to UserControl1

Form1

public partial class Form1 : Form
{
    UserControl2 mySecondControl = new UserControl2();
    public Form1()
    {
        InitializeComponent();
        userControl11.AddControl+=new EventHandler(SwapControls);

    }

    private void SwapControls(object sender, EventArgs e)
    {
        panel1.Controls.Remove(userControl11);
        userControl11.AddControl -= new EventHandler(SwapControls);
        panel1.Controls.Add(mySecondControl);
    }
}

UserControl

public partial class UserControl1 : UserControl
{
    public event EventHandler AddControl;
    public UserControl1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        this.AddControl(this, new EventArgs());
    }
}

Answer 2

Note:

1. Untested code
2. Assuming Form1 has (or can get) a reference to Number

Add an event handler to Number:

public partial class Number : UserControl
{
    //  event handler Form1 will subscribe to
    public EventHandler<EventArgs> OnWelcomeAccepted = (o, e) => { };

    public Number()
    {
        InitializeComponent();
    }

    private void btnAcceptWelcome_Click(object sender, EventArgs e)
    {
          //  raise the event
          OnWelcomeAccepted(sender, e);
    }
}

...Form1 will have a subscription after InitializeComponent(); note the additional subscription to ControlAdded:

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

        this.ControlAdded += Control_Added;
        //  subscribe to the event and provide the implementation
        Number.OnWelcomAccepted += (o, e) => { Controls.Add(GetControl( )); }
    }

    private void Control_Added(object sender, System.Windows.Forms.ControlEventArgs e)
    {
        //  process size and placement and show
    }

}

No other control should be adding anything directly to Form1. Let Form1 control it's children.