Form opening another form within a splitcontainer

Question

I have a main form divided by a splitcontaniner. When I click on a button panel1, a form is loaded into the panel2.

    private void btnCadastrarConta_Click(object sender, EventArgs e)
    {
        stcMenuPrincipal.Panel2.Controls.Clear();
        frmCadastroConta formulario = new frmCadastroConta();
        formulario.TopLevel = false;
        formulario.AutoScroll = true;
        stcMenuPrincipal.Panel2.Controls.Add(formulario);
        formulario.Show();
    }

This form(frmCadastroConta) that was loaded on panel2 has a button that displays another form(frmInformacoesAdicionais).

How do I make for the frmInformacoesAdicionais be carried in the panel2 in place of frmCadastroConta?

Use C#, Net 3.5.

Answer 1

You can remove the frmCadastroCon and add the frmInformationsAdictions the same way he did to add the frmCadastroCon.

Answer 2

You can create an object referring to the other form before entering this button click method, then, to avoid memory Leak, ce deletes this form2 that is inside the Form1 and creates form3 instead of form2 in the form button method.

ce would put there, for example:

TForm3 form3 = new TForm3();
form3.TopLevel = false;
form1.panel2.Controls.Add(form3);
form3.Show();
Close();

Thus form3 would be created, but form2 would be removed from memory. If by chance this is not what you need, if you need to 'hide' the form2, just make the creation of the form3 and the call of it inside the button of the form2, doing a Hide in this form2.

TForm3 form3 = new TForm3();
form3.TopLevel = false;
form1.panel2.Controls.Add(form3);
form3.Show();
Hide();

Although this way make your program occupy more memory, require more processing, for test cases it even serves.

Answer 3

Note: I know the question is old, but I believe the answer can help other users.

Introducing

A solution to this question would be to use Events, events allow classes or objects to notify other classes or objects that a certain action has been performed, allowing those who signed these events to perform some task related to it.

We use events often, a basic example would be the event Click of the component Button, which enables us to do something when a button is clicked.

Codes

I set up a scenario like the one you reported, I set up the name of Form main as frmPrincipal:

using System;
using System.Windows.Forms;

namespace App.Teste
{
    public partial class frmPrincipal : Form
    {
        public frmPrincipal()
        {
            InitializeComponent();
        }

        private void btnCadastrarConta_Click(object sender, EventArgs e)
        {
            stcMenuPrincipal.Panel2.Controls.Clear();
            frmCadastroConta formulario = new frmCadastroConta();
            formulario.TopLevel = false;
            formulario.AutoScroll = true;
            formulario.NextForm += new frmCadastroConta.NextFormEventHandler(formulario_NextForm); // assina o evento
            stcMenuPrincipal.Panel2.Controls.Add(formulario);
            formulario.Show();
        }

        // método que irá tratar o evento
        private void formulario_NextForm(object source, string name)
        {
            ((Form)source).Close();
            if (name == "frmInformacoesAdicionais")
            {
                frmInformacoesAdicionais formulario = new frmInformacoesAdicionais();
                formulario.TopLevel = false;
                formulario.AutoScroll = true;
                stcMenuPrincipal.Panel2.Controls.Add(formulario);
                formulario.Show();
            }
        }
    }
}

In the frmCadastroConta, I created the button btnInformacoesAdicionais that will trigger the event to load the frmInformacoesAdicionais:

using System.Windows.Forms;

namespace App.Teste
{
    public partial class frmCadastroConta : Form
    {

        public delegate void NextFormEventHandler(object source, string name);
        public event NextFormEventHandler NextForm;

        public frmCadastroConta()
        {
            InitializeComponent();
        }

        private void btnInformacoesAdicionais_Click(object sender, System.EventArgs e)
        {
            OnNextForm("frmInformacoesAdicionais");
        }

        public virtual void OnNextForm(string name)
        {
            // verifica se o evento possui algum assinante
            if (NextForm != null)
                NextForm(this, name);
        }
    }
}

The frmInformacoesAdicionais has nothing special, just created a Form with a Label to identify him.

Explanations

The Form that will generate the event is the frmCadastroConta, and what will receive (sign) the event is the frmPrincipal, i.e., the frmCadastroConta will notify the frmPrincipal through the event NextForm that a new Form must be loaded.

These lines below make it possible to use events:

public delegate void NextFormEventHandler(object source, string name);
public event NextFormEventHandler NextForm;

...

public virtual void OnNextForm(string name)
{
    // verifica se o evento possui algum assinante
    if (NextForm != null)
        NextForm(this, name);
}

Declared a Delegate, the event itself and a method to call the event.

Observing: in the statement of delegate you can inform the parameters you find necessary, I added the source to identify which object generated the event and the name to identify which Form carry.

Observation 2: the name of the delegate, the event and the event method (consider using the prefix On as a good practice for this case) it is you who choose.

Done this you must sign the event on frmPrincipal as the line shows:

formulario.NextForm += new frmCadastroConta.NextFormEventHandler(formulario_NextForm);

Observing: you can define the name you think best for your method, not forgetting to declare it with the same parameters of delegate.

The method formulario_NextForm will treat the generated event, which in this case will close the Form who uploaded the event and uploaded the Form passed by the parameter name.

Completion

The use of Events in this case, it leaves its code cleaner and organized, being free of "gambiarras".

References

Communication between Forms in . NET
C# - Events
How to Perform and Cancel the Event Subscription (Programming Guide in C#)