I want to show a hidden object on form 1 from form 2 - vb.net

Question

So I have this PictureBox and Label on form1 which is hidden and I want to show it when you press a Button in form2.
Form1 code:
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.Label3.Hide()
Me.PictureBox3.Hide()
Form2 Code:
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
PictureBox3.Show()
But picturebox3 is not declared in form2 so how can I access it?

Answer 1

There are several ways. As others have stated in answers, the following would be one solution
Declare a public property that returns the PictureBox in Form1
Pass an instance of Form1 to Form2, so Form2 can access this instance of Form1 and use the property
Source could look like this, for example:
In Form1
public PictureBox ThePictureBox
{
get { return this.pictureBox1; }
}
In Form2
private Form1 form1Instance;
public Form2(Form1 form1)
{
InitializeComponent();
form1Instance = form1;
}
public void Button_Click(object sender, EventArgs e)
{
this.form1Instance.ThePictureBox.Visible = true;
}
Another way would be: If Form2 is opened by Form1, you could declare an event in Form2, have Form1 subscribe to it and thus notify Form1 that the picture box should be visible. That way you do not have to expose a member that should otherwise be private to Form1.
This could look like this:
In Form1
private void OpenForm2()
{
Form2 f2 = new Form2();
f2.ShowPictureBox += ShowPictureBox;
f2.Show();
}
private void ShowPictureBox(object sender, EventArgs e)
{
this.pictureBox.Visible = true;
}
In Form2
public event EventHandler<EventArgs> ShowPictureBox;
protected void OnShowPictureBox()
{
if (ShowPictureBox != null)
ShowPictureBox(this, EventArgs.Empty);
}
private void Button_Click(object sender, EventArgs e)
{
OnShowPictureBox();
}
I'm aware of the fact that your example code is Visual Basic, but as you tagged the question "C#" I guess you should be able to translate this to VB.NET easily - my VB.NET is not fluent enough :-)

Answer 2

First of all, you need to be able to access your elements from the other forms (as you should make access modifiers internal or public).
Then you can call the related elements from another form by creating instance or passing the form to a method in other form. You should check this link for detailed explanation by the way.

Answer 3

In some situations, we need to use a control in more than one forms. This can be achieved by sharing the control between different forms
In your case, add the control in Form2 during button click, it should work.
Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
Me.Controls.Add(Form1.PictureBox)
End Sub
Note: Form1.PictureBox is a shared property. We should define it like this in Form1.vb
public Shared Property PictureBox As PictureBox
Get
Return Me.PictureBox3
End Get
End Property