Question

I am trying to find the difference between two dates. The first of the two dates can be changed and when it is changed, the difference between the original dates has to be retained. This means that I have to automatically change the second date to have the same difference in days as it did before, but with a new first date.

Public Sub New()

    InitializeComponent()

    currDate = txt_ProjStart.Text

End Sub

Private Sub txt_ProjStart_TextChanged.....

If txt_ProjEnd.Text.Length > 0 Then

    Dim newDate As Date
    newDate = txt_ProjStart.Text




    Dim endDate As Date
    endDate = txt_ProjEnd.Text


End If

I have the value of the old date1(currDate) and the new date1 value(newDate). I need to get the difference between these, and then add or minus these days from the endDate.

Any help would be much appreciated! Thanks!

Answer 1

Dim newDate, endDate, someOtherDate As Date

If Date.TryParse(txt_ProjStart.Text, newDate) AndAlso _
   Date.TryParse(txt_ProjEnd.Text, endDate) Then

    Dim diff As TimeSpan = endDate - newDate
    Dim result As Date = someOtherDate + diff
End If

Dates and TimeSpans convert into each other automatically. In addition, it would be a good idea to use a safe date conversion. TryParse will not generate an exception, if the date is invalid. Rather it will return False.