Using Default Values

Asknumber and asktext both allow you to supply default values that are automatically placed in the dialog's edit box. If you can reasonably predict what response a user will enter and you supply this default, your model will be much more easy to use. For example, knowing that mortgage terms are usually 30 years, you can change the definition of Term from

Term:=asknumber("Loan term in years?")

to

Term:=asknumber("Loan term in years?",30)

With this change, the Term dialog box will have the value 30 already entered when the dialog box is first displayed. All the user has to do is click Next to accept the value.

In most cases it is difficult to predict what response a user will enter. However, if the model is designed to be run several times, the last value the user entered in a dialog box is the most likely response that will be entered the next time around. You can use the last response as the default value by entering node definitions of the form:

Price:=asknumber("House purchase price?",Price)
Down Payment:=asknumber("Down payment?",Down Payment)
Interest:=asknumber("Annual interest rate?",Interest)
Term:=asknumber("Loan term in years?",Term)

To use a specific default value the first time a model is calculated and then use the value for the previous evaluation on all subsequent recalculations, use a definition of the form:

Term:=asknumber("Loan term in years?",
IF(Term!=null,Term,30))