Eval

Evaluate an expression.

Syntax
      Eval (StringExpr)

Key
   StringExpr  Any expression that returns a string or a number.

The argument stringexpr must be an expression that is stored in a string. If you pass to the Eval function a string that doesn’t contain a numeric expression or a function name but only a simple text string, a run-time error occurs. For example, Eval("Smith") results in an error.

Examples

Eval("1 + 1") returns 2.
Eval("1=2") returns False (-1)
Eval("5 * 10") returns 50

strResult = Eval("MY_Function()")
MsgBox strResult 'displays the result of the function

Dim strName As String
strName = "Forms!frmPatients!txtPatientsName"
MsgBox Eval(strName)
' Returns the patients name,
' i.e. the same as Msgbox Me!txtPatientsName
In general, if there is a more direct way of evaluating an expression without using Eval() you should use it.

“More people are killed every year by pigs than by sharks, which shows you how good we are at evaluating risk” ~ Bruce Schneier

Related

Access Form References - Evaluating references to controls on forms and subforms.
Nz - Detect a NULL value or Zero Length string.