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Using Standard String Templates

  • Artykuł

Several consumers, such as the Active Script Event Consumer or the Command Line Event Consumer, have string properties with the Template qualifier. These properties use standard string templates to construct a string that is configured in part by the consumer instance and in part by an event. The structure of a standard string template is similar to the Microsoft Windows environment variable specification.

The following list shows some examples of the template language:

  • The string "Some text here" always produces the string "Some text here".
  • "%CPUUtilization%" always produces the value of the CPUUtilization property of the event being delivered. If the property is not a string, it is converted to a string; for example, "90" or "TRUE".
  • "The CPU utilization of this processor is %CPUUtilization% at this time" embeds the value of the CPUUtilization property of the event into the string, producing something like, "The CPU utilization of this processor is 90 at this time".
  • "%TargetInstance.CPUUtilization%" retrieves the value of the CPUUtilization property in the embedded instance of the TargetInstance property.
  • "%%" produces a single % sign.
  • If the property being retrieved is an array, the entire array is produced in the following format: "(1,5,10,1024)". If there is only one element in the array, the parentheses are omitted. If there are no elements in the array, "()" is produced.
  • If a property is an embedded object, the MOF representation of the object is produced (similar to the IWbemClassObject::GetObjectText method).
  • If a property of an embedded array of objects is requested, it is treated as a property with an array value. For example: %MyEvents.TargetInstance.DriverLetter% could produce '("C:","D:")' if MyEvents is an array of embedded instance modification events.

String Literals

Anything inside a pair of quotes is considered a string literal and will not be replaced.

The following example shows the string that the compiler sees for "CPU utilization is %CPUUtilization%".

CPU utilization is %CPUUtilization%

This string produces the following output.

CPU utilization is 90

On the other hand, the string "CPU utilization is \"%CPUUtilization%\"" is seen by the compiler as follows.

CPU utilization is "%CPUUtilization%"

This string produces the following output, with no variable substitution.

CPU utilization is "%CPUUtilization%"

Monitoring and Responding to Events with Standard Consumers