Passing the selectionStart property (monthCalendar) between forms (winforms c#)

Question

I have a calendar control on one form (statsform) that I am calling from another form exportform:

here is the code in statsform where I instantiate exportform:

private void export_Click(object sender, EventArgs e)
        {

            if (formIsHidden == 0)
            {
                ExportForm exportForm = new ExportForm();
                exportForm.Show();
                formIsHidden = 1;
            }

        }

I update the date in the calendar control in statsform every time it is clicked:

public void monthCalendar1_DateChanged(object sender, DateRangeEventArgs e)
        {
            dateFromLabel.Text = dateFromCalendar.SelectionStart.ToString("dd/MM/yyyy");   
        }

        public void monthCalendar2_DateChanged(object sender, DateRangeEventArgs e)
        {
            dateToLabel.Text = dateToCalendar.SelectionStart.ToString("dd/MM/yyyy"); 
        }

Here is the code from form2 (trying to get selectionStart Property and use it)

(On button click)

statsform statsform = new statsform();

string startDate = statsform.dateFromCalendar.SelectionStart.ToString("yyyy-MM-dd 00:00:00");
string endDate = statsform.dateToCalendar.SelectionStart.ToString("yyyy-MM-dd 23:59.00");

(Pass date to SQL Queries)

However, the selected date is not passed to exportform, only the current date is passed when i create a breakpoint and inspect the strings.

Is it because I am creating a new instance of the form? How can I pass the user selected date form the form to the second form?

statsform(create Calendar) -> exportform (button click event - retrieve selectedDate from statsform calendar control)

My solution:

public ExportForm(statsform parent)
        {
            InitializeComponent();
            statsform = parent;

        }

Allowed me to use the existing instance of the form. I needed the (this) in the constructor though so thanks for all the help.

Answer 1

You could set up a parameter on your exportform’s constructor when you instantiate it to pass a reference to your first form, then reference those properties directly.

So inside your exportform’s class

private statsform _statsform = null;

public exportform(statsform caller) {
    _statsform = caller;
}

Then when you instantiate it

ExportForm exportForm = new ExportForm(this);

And from your button click code you reference the labels in your statsform

var fromDate = _statsform.dateFromCalendar.... etc

More info on constructors here https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/constructors