array size check

[RycherX]

How do I check the size of an array? I want a condition where BlockList() has nothing in it.



Dim BlockList() As String


If BlockList size is 0 Then
end if

[MrPolite]

If BlockList.Length =0 Then
Use "is" for reference types only

[jmcilhinney]

Be aware that, while the Length property is a value type, the array itself is a reference type. This code:

        Dim myArray() As String

        If myArray.Length = 0 Then
            MessageBox.Show("No elements.")
        End If

will throw an exception because no Array object has been created. To create an array with no elements, use this code:

Dim myArray(-1) As String

or

Dim myArray() As String = New String(-1) {}

or

Dim myArray() As String = {}

The array variable is a null reference until you either specify the upper bound of each dimension or assign an existing array object to it.