在用户控件中显示/隐藏面板 Form1

Question

Anyone know how can I hide/show panel of Form1 but my button is in UserControl , I want to add button in UserControl to hide and show panel of Form1 . How can i do that?

Here's my code for hide and show:

private void button3_Click_1(object sender, EventArgs e)
{
    flag *= -1;
    if (flag == 1)
        bunifuGradientPanel1.Hide();
    else
        bunifuGradientPanel1.Show();
}

Answer 1

Controls should not know about their containers explicitly, in order to maintain loose coupling. Any control can call its FindForm method to get a reference to its form of type Form . That should only be used to do general form things though. A child control should not know that its parent form is a specific type, never mind what that type contains.

The proper way to do this is for the user control to raise an event. That event can notify any listeners that something has happened and those listeners can then do whatever is required. In this case, the form would handle the event of the user control and then hide its own Panel .

The user control might contain code like this:

public event EventHandler Button1Click;

protected void OnButton1Click(EventArgs e)
{
    Button1Click?.Invoke(this, e);
}

private void button1_Click(object sender, EventArgs e)
{
    OnButton1Click(EventArgs.Empty);
}

For more information on raising your own events, see here .

When the user clicks button1 on the user control, that user control will raise its Button1Click event. The form containing the user control can then handle that event and do whatever is required, just as it could handle the Click event of a regular Button and do whatever is required, eg

private void someUserControl1_Button1Click(object sender, EventArgs e)
{
    panel1.Visible = !panel1.Visible;
}