Question

I have a form that has a combobox . I need this combobox value to remain unchanged even if the user closes and reopens the form. The value should remain constant, unless the user updates it, then the updated field will remain constant.

Answer 1

Then you need to store the selected value somewhere – depending on the lifetime you need to decide where.

If you are closing and opening the entire application then you will need to store the value in a database or file – an xml file may be your best bet.

If you only need to keep it unchanged for the lifetime of the application then you can store it in memory – lets say in a static variable of the form, the following demonstrates that option:

public partial class Form1 : Form
{
    static string selection;
    public Form1()
    {
        InitializeComponent();
        comboBox1.SelectedItem = selection;
    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        selection = (string)comboBox1.SelectedItem;
    }
}