Try catch if selected excel file is blank - vb.net

Question

Hello I have a program that imports an excel file using the oledb in vb.net. This program imports the excel spreadsheet into a datagridview. On opening the program will ask the user to choose an excel file to open, however if the user inputs nothing or presses the cancel button the program will crash. I'm trying to find a way to prevent a user from canceling or leaving the excel filename blank. I'm hoping this will be done using a try catch block but I'm not exactly familiar with try catch in vb.net. If anyone has any suggestions or solutions for this I would greatly appreciate it. This is what I found on MSDN.
If System.IO.File.Exists(filePath) = False Then
Console.Write("File Not Found: " & filePath)
Else
' Open the text file and display its contents.
Dim sr As System.IO.StreamReader =
System.IO.File.OpenText(filePath)
Console.Write(sr.ReadToEnd)
sr.Close()
End If

Answer 1

You could try a Try....Catch loop. Check this site out, should give you what you are looking for.
You could possibly use the Try....Catch loop and on the catch have an error message saying they must fill in the blank textbox.

Answer 2

I would suggest to take care of this at the source, when opening the file, and catching errors after the fact should be a last resort.
If filePath <> String.Empty And System.IO.File.Exists(filePath) Then
Try
'handle the opening of the file
Catch ex As Exception
Console.Write(ex.Message)
End Try
ElseIf filePath = String.Empty Then
Console.Write("Nothing Entered")
Else
Console.Write("File Not Found: " & filePath)
End If