Question

I have a form and multiple controls.

Say I have a single form and it should contain some controls.

I’m trying to work with a single form and add and remove controls depending on some use cases.

For example, this is a sample code in my form class:

private void AddToControlPanel(UserControl control)
        {
            this.panelControl.Controls.Add(control);
            this.panelControl.Tag = control;
            this.panelControl.Size = control.Size;
            this.panelControl.Dock = DockStyle.Fill;
            control.Show();
        }

Above sample adds a control to some panel and shows it.

Problem is I can’t manage to add some other control and drop current one. For example, if some login control authenticates successfully, drop login control itself and show other like a search box control.

How can achieve that?

This is what I’ve tried so far:

if (LoginOK)
{
   //Add the next Control I want to load
   this.ParentForm.Controls.Add(new CtlPedirDevolucion());
   //Remove this actual control
   this.ParentForm.Controls.Remove(this);
}

… so later show latest added control using an event handler:

private void FirstForm_ControlRemoved(object sender, ControlEventArgs e)
{
    this.Controls[this.Controls.Count - 1].Show();
}

But this isn’t working for me. In addition I don’t like my approach.

Will you suggest me a better way of achieving this please?

Answer 1

I have tried something similar and it works.

Code in your Form:

public void SwitchControls(Control removeCtrl, Control addControl)
{
     panel1.Controls.Remove(removeCtrl);
     panel1.Controls.Add(addControl);
}

Code in your Control:

MyForm frm = (MyForm)this.FindForm();
CtlPedirDevolucion newCtrl = new CtlPedirDevolucion();
newCtrl.Dosck = DockStyle.Fill;
frm.SwitchControls(this, newCtrl);

EDIT: My bad, there is no point creating a CtlPedirDevolucion in control that will be removed. It should be instantiated in your Form and there should also be a reference to it. Therefore SwitchControls should have a more complex logic, and maybe more parameters but this is something you can work with. Maybe you could make a switch-case or something that will create a control within your form. I remind you that this is just an example that works but is very bad.