How Can I Access a ListBox's SelectedIndex from Another Form in C#?

Accessing Form Controls from Another Form

Problem: Accessing the SelectedIndex property of a ListBox control from a different form (Form 2) can be challenging.

Current Solution:
Utilizing a property in the main form (Form 1) to set the SelectedIndex value is a feasible approach.

Improved Solution:
Consider passing the reference of Form 1 to Form 2 through an overloaded constructor. This allows Form 2 to directly access the SelectedIndex property and manipulate it accordingly.

Sample Code:

Form 1:

public partial class Form1 : Form
{
    public int SelectedIndex
    {
        set { listBoxControl.SelectedIndex = value; }
    }
    ...
}

Form 2:

public partial class Form2 : Form
{
    private Form1 mainForm;
    public Form2(Form1 callingForm)
    {
        InitializeComponent();
        mainForm = callingForm;
    }
    ...
    public void SomeMethod()
    {
        mainForm.SelectedIndex = -1;
    }
}

Benefits:

• Direct access to Form 1's properties from Form 2.
• No need for indirect or global variables.
• Flexibility in communication between forms.

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