The VBA IsNull Function

Related Functions:

Description

The VBA IsNull function returns a Boolean, indicating whether a supplied expression is Null.

The syntax of the function is:

IsNull( Expression )

Where the supplied Expression is the expression that you want to test.

The following example supplies three different variables to the VBA IsNull function.

' Test if three variables are Null.

								Dim var1, var2, var3

								Dim isNull1 As Boolean

								Dim isNull2 As Boolean

								Dim isNull3 As Boolean

								var1 = 5

								isNull1 = IsNull( var1 )

								' The variable isNull1 is now equal to False.

								var2 = Null

								isNull2 = IsNull( var2 )

								' The variable isNull2 is now equal to True.

isNull3 = IsNull( var3 )
' The variable isNull3 is now equal to False.

The above examples show that the IsNull function returns:

True for variables that have been set equal to Null;
False for variables that have been assigned other values or have not yet been initialized.