Pass form object value to static method

I need to take a form object value and pass it into开发者_运维问答 a static method:

 public void SetCalendarStartSafe(DateTime startDateSafe)
 {
     startDateSafe = calendarStart.Value;
 }   

 private static DataTable GetData()
 {
     frmMain frm = new frmMain();
     DateTime startDate = new frmMain();
     frm.SetCalendarStartSafe(startDate);
 }

However I keep getting today's current date whenever I try this approach, even if the specified calendar date on the form is different. How can I can the user-specified calendar date from the original frmMain object? Thanks in advance for any guidance.

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you will be calling GetData() from somewhere in the code which is non-static? like for example from some event in the Form.. in that event pass the parameter to the static method GetData(DateTime..)

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public void SetCalendarStartSafe(DateTime startDateSafe)
{
    // wrong:
    // startDateSafe = calendarStart.Value;
    // right:
    calendarStart.Value = startDateSafe;
} 

There, just swap those two around. The destination of the assignment is on the left.