Default Value Binding¶
Default Value binding allows application to display the default value when the first expression is evaluated to undefined
, null
or empty string
.
Indicator¶
-
The
$
indicator could be applied to all properties value includingstring
literal, binding, globals,ActionBar
,ToolBar
,FormCell
controls,Sections
controls,Extension
controls. -
The key is
DV
-
It consists of two parameters, the first parameter is for target expression, and the second parameter for default value.
-
It is advised to add single quote (\') for string literal within the indicator to mark the start and end of the string value, e.g.
$(DV,'{Binding}','Unknown')
-
The supported value types for parameter are
string
,integer
,boolean
,Resolvable
value types. -
Complex types (
array
andobject
) are not supported as parameter value. -
Specify
null
, If no value is to be set on one of the platform parameters.
Description¶
Return the specified string
according to platform
Usage¶
$(DV, <Target expression>, <Value for default>)
Parameters:
Parameter Name | Type | Required? | Description |
---|---|---|---|
Target expression | String Literal , ResolvableValue |
Mandatory | Expression will be evaluated |
Value for default | String Literal, ResolvableValue |
Optional | Default value if the Target expression being evaluated to undefined, null or empty string |
Examples¶
$(DV, ,'The default text')
$(DV, null, 'Unknown value')
$(DV, '', 'empty string')
Prefix $(DV, {SomeProperty},'Can\'t find the property') {SomeObject/ObjectPropertyA}
$(DV, #ClientData/TargetPath/SomeObject/ObjectPropertyA, '/MDKDevApp/Rules/TextForIOS.js')
$(DV, '/MDKDevApp/Globals/Empty.global', '$(L,see_more)')
$(DV, {SomeObject/NullProperty}, '{#Application/#ClientData/MobileServiceAppId}')
$(PLT, $(DV, '/MDKDevApp/Globals/Empty.global', '/MDKDevApp/Rules/TextForIOS.js'), $(DV, '/MDKDevApp/Globals/Empty.global', '/MDKDevApp/Rules/TextForAndroid.js'))