Fabulous.CodeGen

Root

{
    "assemblies": [
        "path/to/A.dll",
        "path/to/B.dll"
    ],
    "outputNamespace": "My.Namespace",
    "types": [
        // See Type
    ]
}

Field	Type	Required	Description
Assemblies	string array	✅ Yes	Paths to dlls containing controls (can be relative to working directory)
OutputNamespace	string	✅ Yes	Namespace under which all the generated code will be added
Types	Type array	✅ Yes	All types to bind

Type

{
    "type": "Xamarin.Forms.ListView",
    "customType": "Fabulous.XamarinForms.CustomListView",
    "canBeInstantiated": true,
    "name": "ListView",
    "properties": [
        // See Property
    ],
    "events": [
        // See Event
    ],
    "attachedProperties": [
        // See Attached Property
    ]
}

Field	Type	Required	Description
Type	string	✅ Yes	Full name of a control inside one of the dlls to bind
CustomType	string	❌ No	If specified, this type will be used when instantiating this control instead of the binded type. Not necessary that the control exists at generation time
CanBeInstantiated	boolean	❌ No	Indicates if the code generator should provide a public constructor for this type. If not specified, the value defaults to `true`
Name	boolean	❌ No	The name that will be used when generating code (e.g. `View.MyCustomControl()`). If not specified, the name will be inferred from the `Type` field
Properties	Property array	❌ No	All properties of this control to include in the code generation
Events	Event array	❌ No	All events of this control to include in the code generation
AttachedProperties	AttachedProperty array	❌ No	All attached properties of this control to include in the code generation

Property

{
    "source": "Source",
    "name": "Name",
    "uniqueName": "UniqueName",
    "shortName": "shortName",
    "defaultValue": "DefaultValue",
    "elementType": "ElementType",
    "inputType": "InputType",
    "modelType": "ModelType",
    "convertInputToModel": "(fun input: InputType -> input :?> ModelType)",
    "convertModelToValue": "(fun model: ModelType-> model :?> ValueType)",
    "updateCode": "(fun prev curr target -> ())"
}

Field	Type	Required	Description	Remarks
Source	string	❓Depends	Name of the property to include (and overwrite)
Name	string	❓Depends	Name of the property used in the generated code (e.g. `buttonViewElement.MyProperty(value)`)	If not specified, `Source` will be used instead
UniqueName	string	❌ No	Name to uniquely identify the property in the generated code	Use with caution. If not specified, `Type` and `Name` will be concatenated to create a unique name. (e.g. `ButtonText`). Subject to optimization
ShortName	string	❌ No	Name (lower camel case) to use in ViewElement constructor (e.g. `View.Button(myProperty=value)`)	If not specified, `Name` will be used in lower camel case
DefaultValue	string	❓Depends	Default value to apply to the property if none is given by the user (e.g. `0.0f`)
ElementType	string	❓Depends	(Apply only if property is a collection) Full name of the item type of the collection	If `null`, the property is not considered to be a collection
InputType	string	❓Depends	Type expected in the constructor (e.g. `string` => `View.Button(text = "some string")`)
ModelType	string	❌ No	Type as which the value will be stored in the ViewElement attributes dictionary	Make sure this type is efficient
ConvertInputToModel	string	❌ No	Function to convert the input value to the model type	Expects a signature of type `'Input -> 'Model`. Function can be written directly inside the json, or make a reference to a function. If not specified, no conversion will be applied.
ConvertModelToValue	string	❌ No	Function to convert the model value to the expected type of the real property	Expects a signature of type `'Model -> 'Value`. Function can be written directly inside the json, or make a reference to a function. If not specified, no conversion will be applied.
UpdateCode	string	❌ No	Function to use instead of the generated view diffing for this property	Expects a signature of type `prev: ViewElement -> curr: ViewElement -> target: ControlType -> unit`. Function can be written directly inside the json, or make a reference to a function. If not specified, the default view diffing code will be used.

There is 3 different categories of property:

Existing scalar property: A property present in one of the dlls to include with a simple data type
Existing collection property: A property present in one of the dlls to include which is a collection (e.g. Xamarin.Forms.View list)
Dummy property: A non-existent property to include which can be either of type scalar or collection

See examples for these categories below.

Event

{
    "source": "TextChanged",
    "name": "TextChanged",
    "uniqueName": "EntryTextChanged",
    "shortName": "textChanged",
    "inputType": "Xamarin.Forms.TextChangedEventArgs -> unit",
    "modelType": "System.EventHandler<Xamarin.Forms.TextChangedEventArgs>",
    "convertInputToModel": "(fun f -> System.EventHandler<Xamarin.Forms.TextChangedEventArgs>(fun _sender _args -> f args))"
}

Field	Type	Required	Description	Remarks
Source	string	❓Depends	Name of the event to include (and overwrite)
Name	string	❓Depends	Name of the event used in the generated code (e.g. `entryViewElement.TextChanged(value)`)	If not specified, `Source` will be used instead
UniqueName	string	❌ No	Name to uniquely identify the event in the generated code	Use with caution. If not specified, `Type` and `Name` will be concatenated to create a unique name. (e.g. `EntryTextChanged`). Subject to optimization
ShortName	string	❌ No	Name (lower camel case) to use in ViewElement constructor (e.g. `View.Button(myProperty=value)`)	If not specified, `Name` will be used in lower camel case
InputType	string	❓Depends	Type expected in the constructor (e.g. `Xamarin.Forms.TextChangedEventArgs -> unit` => `View.Button(textChanged = (fun args -> ()))`)	Expects a function
ModelType	string	❓Depends	Type as which the value will be stored in the ViewElement attributes dictionary	Expects an EventHandler
ConvertInputToModel	string	❓Depends	Function to convert the input value to the model type	Expects a signature of type `'Input -> 'Model`. Function can be written directly inside the json, or make a reference to a function. If not specified, no conversion will be applied.

AttachedProperty

{
    "source": "Source",
    "name": "Name",
    "uniqueName": "UniqueName",
    "defaultValue": "DefaultValue",
    "elementType": "ElementType",
    "inputType": "InputType",
    "modelType": "ModelType",
    "convertInputToModel": "(fun input -> input :?> Model)",
    "convertModelToValue": "(fun model -> model :?> Value)",
    "updateCode": "(fun prev curr target -> ())"
}

Field	Type	Required	Description	Remarks
Source	string	❓ Depends	Name of the attached property to include (and overwrite)
TargetType	string	❌ No	Type to which this attached property will be applied to	If not specified, a default base target type will be applied
Name	string	❓ Depends	Name of the property used in the generated code (e.g. `buttonViewElement.MyProperty(value)`)	If not specified, `Source` will be used instead
UniqueName	string	❌ No	Name to uniquely identify the property in the generated code	Use with caution. If not specified, `Type` and `Name` will be concatenated to create a unique name. (e.g. `ButtonText`). Subject to optimization
DefaultValue	string	❓ Depends	Default value to apply to the property if none is given by the user (e.g. `0.0f`)	If not specified, `Name` will be used in lower camel case
ElementType	string	❓ Depends	(Apply only if attached property is a collection) Full name of the item type of the collection	If `null`, the attached property is not considered to be a collection
InputType	string	❓ Depends	Type expected in the constructor (e.g. `string` => `View.Button(text = "some string")`)
ModelType	string	❌ No	Type as which the value will be stored in the ViewElement attributes dictionary	Make sure this type is efficient
ConvertInputToModel	string	❌ No	Function to convert the input value to the model type	Expects a signature of type `'Input -> 'Model`. Function can be written directly inside the json, or make a reference to a function. If not specified, no conversion will be applied.
ConvertModelToValue	string	❌ No	Function to convert the model value to the expected type of the real property	Expects a signature of type `'Model -> 'Value`. Function can be written directly inside the json, or make a reference to a function. If not specified, no conversion will be applied.
UpdateCode	string	❌ No	Function to use instead of the generated view diffing for this property	Expects a signature of type `prev: ViewElement -> curr: ViewElement -> target: ControlType -> unit`. Function can be written directly inside the json, or make a reference to a function. If not specified, the default view diffing code will be used.

Examples

Example properties

Existing scalar property

{
    "source": "Margin",
    "name": "Margin",
    "uniqueName": "VisualElementMargin",
    "shortName": "margin",
    "inputType": "InputTypes.Thickness",
    "modelType": "Thickness",
    "convertInputToModel": "ViewConverters.convertThickness",
    "convertModelToValue": null
}

Field	Type	Required
Source	string	✅ Yes
Name	string	❌ No
UniqueName	string	❌ No
ShortName	string	❌ No
InputType	string	❌ No
ModelType	string	❌ No
ConvertInputToModel	string	❌ No
ConvertModelToValue	string	❌ No
UpdateCode	string	❌ No

Existing collection property

{
    "source": "ItemsSource",
    "name": "Items",
    "uniqueName": "GridItems",
    "shortName": "items",
    "elementType": "Xamarin.Forms.View",
    "inputType": "ViewElement list",
    "modelType": "ViewElement array",
    "convertInputToModel": "Array.ofList"
}

Field	Type	Required	Remarks
Source	string	✅ Yes
Name	string	❌ No
UniqueName	string	❌ No
ShortName	string	❌ No
ElementType	string	❓ Depends	Usually automatically detected by the AssemblyReader step. If correct, no need to specify it.
InputType	string	❌ No
ModelType	string	❌ No
ConvertInputToModel	string	❌ No
ConvertModelToValue	string	❌ No
UpdateCode	string	❌ No

Dummy property

{
    "source": null,
    "name": "Name",
    "inputType": "InputType"
}

Field	Type	Required	Remarks
Source	string	❌ No	Must be `null` or not declared
Name	string	✅ Yes
UniqueName	string	❌ No
ShortName	string	❌ No
ElementType	string	❓ Depends	Must be declared if property is a collection
InputType	string	✅ Yes
ModelType	string	❌ No
ConvertInputToModel	string	❌ No
ConvertModelToValue	string	❌ No
UpdateCode	string	❌ No

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Fabulous.CodeGen

Root #

Type #

Property #

Event #

AttachedProperty #

Examples #

Example properties #

Existing scalar property #

Existing collection property #

Dummy property #

Root

Type

Property

Event

AttachedProperty

Examples

Example properties

Existing scalar property

Existing collection property

Dummy property