Data Type Functions
VB provides several functions that work with the
data type of their arguments instead of the argument
values:
- The data-inspecting functions IsDate(), IsNull(),
IsNumeric(), and varType()
- The IIf() and choose() shortcut functions
- The data type conversion functions
The Data-Inspection Functions
The data-inspection functions inspect data types
and special contents of variables. The following table
lists these functions:
| Function name |
Description |
| IsDate() |
Returns a Boolean
value indicating whether an expression can be
converted to a date. |
| IsEmpty() |
Returns a Boolean
value indicating whether a variable has been
initialized. |
| IsNull() |
Determines whether
its argument holds a Null value. |
| IsNumeric() |
Returns a Boolean
value indicating whether an expression can be
evaluated as a number. |
 |
Use IsNull() to see whether a control
or field on a report or form contains data. Use
IsEmpty() just for variables. |
|
