Using If statement to verify if string value is in an array of strings

Question

I have a string and an array of strings. I was wondering if it is possible to use an If statement in order to return a boolean value if the string contains a value from the array.

The code below doesn't work properly. Contains can only take in one value as far as I can see. Is there a better way to do this without having to use a loop?

Dim FilePath As String = "C:\Users\Downloads\Test.jpg"
Dim GetExtension As String = FilePath.Substring(FilePath.Length - 3)
Dim FileExtensionArray() As String = {".png", ".jpg", ".tif"}

If GetExtension.Contains(FileExtension) = True Then
   ' Code
Else
   ' Code
End If

Have a look at this one stackoverflow.com/questions/18952971/… — Andrew Mortimer
– Andrew Mortimer, Commented Aug 28, 2019 at 10:42
Possible duplicate of check if string contains any of the elements of a stringarray (vb net) — Anu6is
– Anu6is, Commented Aug 28, 2019 at 10:44
That is a good solution to my problem. However, I was wondering if it was possible to do without a loop :) — user4743021
– user4743021, Commented Aug 28, 2019 at 10:47

video.baba · Accepted Answer · 2019-08-29 04:19:41Z

2

Just a couple of things to note about your code:

Dim GetExtension As String = FilePath.Substring(FilePath.Length - 3)
Dim FileExtensionArray() As String = {".png", ".jpg", ".tif"}

GetExtension now contains jpg but your arrays are .jpg. There's some built-in help already available for file extensions:

IO.Path.GetExtension(FilePath)

Lastly, your If .... Then test is the wrong way round. With a couple of simple adjustments I'd use this:

    Dim FilePath As String = "C:\Users\Downloads\Test.jpg"
    Dim FilePathExtension As String = IO.Path.GetExtension(FilePath)
    Dim FileExtensionArray As String() = {".png", ".jpg", ".tif"}

    If FileExtensionArray.Contains(FilePathExtension) Then
        'yes
    Else
        'no
    End If

answered Aug 29, 2019 at 4:19

video.baba

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Comments

alekini · Accepted Answer · 2019-08-28 14:33:08Z

0

Maybe you could convert FileExtensionArray in a string with the function Join:

 GetExtensionsJoin= String.Join( "-", FileExtensionArray)

After that, you could use the method "contains" to check if string contains the extension.

 GetExtensionsJoin.contains(GetExtension)

answered Aug 28, 2019 at 14:33

alekini

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1 Comment

Fabio Over a year ago

This will return true for a wrong reasons. For example when file extension is a substring of any of allowed extensions.

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