Hi *,
I have a screen in a PowerApps with selection of a start and end time, divided into hours and minutes:

These are 4 dropdown boxes with preassigned choices, here as an example a dropdown box for minutes in 15 minute increments:

Now I want to write all 4 values together in a SharePoint column. For this I set a variable for each dropdown box at OnChange, e.g. Set(varMinStart; Self.Selected) and build a string from the 4 variables, which I then pass to a TextBox, which then writes to the SharePoint list via SubmitForm:
varStdStart.Value & ":" & varMinStart.Value & " - " & varStdEnd.Value & ":" & varMinEnd.Value & " Uhr"

This works now also so far. But if the user now selects only the hours and no minutes, then the variables for the minutes are not filled and there is now an unsightly output:

Now I'm looking for a way how I can set the value for the minutes as default to "00" in such a case, so that it looks like this again:

My second problem with this is how I can prevent a value greater than the end time from being selected as the start time, so like this:

Does anyone have any ideas about this?
Many thanks in advance.
Regards
Herb