Foglight 7.1.0 - Web Component Tutorial

Parameters in Bindings

Most types of bindings have parameters. These are placeholders nested within the binding that are also evaluated at run time. An example is a String Template binding set to Host: {0}. In this case Host: is a fixed string, while {0} is a reference to a parameter that evaluates to the name of the host server by configuring that association to a particular dynamic context at the time when the String Template binding is being defined. Each description of the binding type explains how to use parameters.

CAUTION: Any quotation mark you use in the parameterized string must be escaped. For example, if the text string that you want to use is The host’s name is: {0}, you must escape the apostrophe using the back slash character ‘\’ as follows: The host\’s name is: {0}.If the text string includes a back slash character ‘\’, use double back slashes, “\\” to represent the back slash in the string.

For more information, see Bindings.

On Null Values

Most types of binding have an associated On Null binding. This provides an alternate value that can be used if the main binding evaluates to null (nothing) or an empty list of values.

Renderers

A renderer may be specified on each type of binding. A renderer determines how the evaluated value is displayed. For example, a limit to the length of a string, the number of decimal places, or the date and time format. If no renderer is specified, then a default renderer based on the object’s type is used. Therefore, in most cases, an explicitly set renderer is not required.

Null and error renderers, noted earlier in the list of simple types, are special cases of renderers. They are only used to display no data or error information. Unlike normal renderers, they do not base their behavior on the data being rendered, but instead have fixed outputs. A drop-down menu lists all the available renderers. Generally, you can determine which renderer to select based on its name. If no renderer is specified, renderers are looked up from the type, property and unit of the value. If no renderer is found, a default renderer is used. Therefore, in most cases, a renderer is not required.

For more information, see Renderers.

Default Values

If a property has a default value it is displayed as text beside the edit icon in the Value column of the tree table in the Configuration tab. A property that has been configured to use a specific value can be set back to its default property by clicking the Edit icon, then selecting Clear to default from the drop-down menu.