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Condition Guidelines
Windows Installer Editor Reference
Conditions attached to control events
You can attach an event to a control. The event can have an associated condition.
You might attach events to Next buttons that specify what event happens if the Next
button is clicked.
Example: Click the Installation Type dialog in Setup Editor > Dialogs tab. Double-
click the Next button and click the Events tab on the Properties dialog box.
Depending on what the property InstallMode is set to, different dialog boxes appear,
as specified in the NewDialog events. If the end user selects the Custom radio
button, InstallMode is set to Custom, and the Select Feature dialog appears. If the
end user does not select the Custom radio button, the Start Installation dialog
appears. The value of the InstallMode property is determined by the end user's radio
button choice.
Conditions attached to components
You can attach conditions to components in Setup Editor > Components tab. (You can
also add them to components on the Features tab.) If you attach a condition to a
component, the component is installed only if the condition is true. To add or change a
condition attached to a component, right-click a component icon and select Details. Use
the Condition field on the Component Details dialog box that appears to add or change
a condition.
If you add conditions to the Features page, and add items to the conditions using the
Current Feature drop-down list at the top of Installation Expert pages, then some of
the components on the Components tab will have conditions set.
Note
If you add a component condition that checks the installed state of a component or
feature, add the merge module CondFix.msm to the installation. This merge module
fixes a Windows Installer limitation.
See
WiseFixConditions
on page 440.
Before creating conditions, become familiar with the following Windows Installer
guidelines for creating conditions.
You can use the following types of values inside a condition:
The name of the property. This is case-sensitive. You do not need to enclose the
property name in square brackets. See Using Properties in Conditional
Statements in the Windows Installer SDK Help.
Any integer between -32,767 and 32,767. You cannot use floating point values.
String literal. Enclose text in quotation marks. Properties that have not been set
evaluate to an empty string "" (null).
Environment variable. Precede the variable name with a percent symbol (%).
If a property is set, it evaluates to true in a Boolean expression.
Example: If the installation runs on a destination computer whose operating system
is later than ME, the property VersionNT is set to the version number of the
operating system. However, if you want to set a condition to check for these
operating systems, you can enter the condition as VersionNT. If VersionNT is set to
anything at all, even 0, the condition evaluates to true.
Using Conditions and Properties
439
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