Where can placeholders be used?

You can use placeholders in property values, rules and actions. There, each placeholder is replaced at runtime by the value that is assigned to the placeholder in the placed faceplate.

How do I define a placeholder?

Placeholders are defined in the Placeholders tab of the Faceplate inspector.

In the right-hand input field Placeholder , enter the placeholder as you would like to use it in other places within the faceplate. This can be a single character or a character string. Please note that if you change the placeholder afterwards, not all occurrences of this placeholder in the faceplate are automatically updated. For example, if you change the placeholder from “*” to “^”, you must adjust the placeholders in all property values, rules and actions.

In the Name input field on the left, assign a unique name under which this placeholder will later be displayed in the placed faceplate under the other properties.

How do I use a placeholder?

You use a placeholder by using the value that you have defined as a placeholder in any position. The placeholder is automatically replaced at runtime.

Example property value

For example, if you select a label within a faceplate, you can specify the value “Output *” as the text property:

As you have previously defined the placeholder “*” with the name “Output”, this placeholder is now available to you as a property of the placed faceplate:

Placeholders are not yet evaluated in the editor; it is only at runtime that the placeholder is replaced by the value “1”.

Example property rule

Within a faceplate, you can of course edit the properties and events of the control elements in the same way as you can on a simple page.

You can also create rules and actions that are then processed or evaluated in exactly the same way for all placed faceplates.

However, if you place a faceplate several times, you also have the option of using placeholders to dynamically reference the rules and actions within the faceplate to different variables. Instead of a specific variable, you simply enter a name. This name can contain placeholders that are replaced at runtime.

In the example above, we have bound the “IsUsed” property of the upper conveyor technology element with a rule to the value “test.isused_output*_ft_1”. We can now assign the placeholder (*) individually for each faceplate placed.