Question

How do I calculate the difference between two dates to display as a number in days?

I have 2 text boxes (txtHStart_Date & txtHEnd_Date) I have used an Ajax Calendar Extender to enter the dates in each of these text boxes.
I would like to get the difference between these two dates to show in a seperate text box (txtNoOfDays)

I’ve seen the timespan function but can seem to get this to work.
I’m not to sure how to declare the text boxes as the dates I would the calculation to be made from

Code:

Dim D1 As Date
Dim D2 As Date
Dim ts As New TimeSpan
D1 = txtHStart_Date.Text
D2 = txtHEnd_Date.Text
ts = D2 - D1

But I know this isn’t right. I also don’t know how to get it to display in the 3rd TextBox.

Answer 1

The TimeSpan is simple to use.

Dim dtStart As DateTime = DateTime.Now.AddDays(-100)
Dim dtEnd As DateTime = DateTime.Now

Dim ts As TimeSpan = dtEnd - dtStart
Console.WriteLine(ts.TotalDays)

Edit:

And going by the comment you added where you assign a text string to a date variable, you would be better off using (and handling)

DateTime.TryParse("some date string", dtStart)

TryParse returns a boolean success/fail so you can react to whether you were given good/bad data.