How to check if a string array is null?

Question

I modified a workflow in TFS template, in the head of this workflow I initialized an array of string named NextChainBuildDefinition. After a few steps, I tried to check if this array is null or not.

I did this way:

String.IsNullOrEmpty(CStr(NextChainBuildDefinition.Count))

After this I see error: Exception Message: Value cannot be null. Therefore NextChainBuildDefinition is null, and in that step it throws an exception.

How do I check if this string array is null?

Answer 1

You need to check if the array itself is null or empty - your current code is checking if the string conversion of the number of elements in the array is empty - this isn't going to work at all.

Instead, you need to do a two step check - both for if the array itself is null, and if not, if it's empty:

If (NextChainBuildDefinition IsNot Nothing AndAlso NextChainBuildDefinition.Count > 0) Then
  'Array has contents
Else
  'Array is null or empty
End if