Set Variant Variable to Null Method
The Set Variant Variable to Null method sets a variant variable to a value of Null. It returns a variant that is set to NULL. Note that Visual Basic sets a variant to the empty value, which is different from the Null value.
Format
variableName = Null
The Set Variant Variable to Null method does not include arguments.
Example
The following example calculates the average of ten test score values. If any score is negative, then it sets this value to Null. Before this example calculates the average, the IsNull statement reduces the total count of scores to only those scores that are positive values:
Sub Button_Click
Dim arrayvar(10)
Dim count as Integer
Dim total as Integer
Dim x as Integer
Dim tscore as Single
count = 10
total = 0
For x = 1 to count
tscore = 88
If tscore < 0 then
arrayvar(x) = Null
Else
arrayvar(x) = tscore
total = total + arrayvar(x)
End If
Next x
Do While x <> 0
x = x - 1
If IsNull(arrayvar(x)) = -1 then
count = count - 1
End If
Loop
msgtext = " The average (excluding negative values) is: "
msgtext = msgtext & Chr(10) & Format (total/count, "##.##")
End Sub