Code Example of Key Binding 

As mentioned under Key Binding, you can use this binding concept only for data types that can provide a value set of key value pairs. This requires either the definition of a specific data type in the Java Directory or the extension of the data type String with metadata at runtime. We recommend defining new data types if the data type in the application is used frequently or the Web application is to be executed using the Java Dictionary.

Example A

The following source code is an example of key binding, where the data type String is modified at runtime.

1. Defining the Context at Design Time (Creating a Context Attribute as a Root Node Attribute):

Value attribute "MonthName”, type=”String”.

2. Initializing Node Elements In the wdDolnit Method:

//Get access to data type instance to be modified at runtime ISimpleTypeModifiable myType=wdThis.wdGetAPI().getContext().getModifiableTypeOf("MonthName");   //Set valid values for this data type   IModifiableSimpleValueSet values=myType.getSVServices().getModifiableSimpleValueSet();    values.put("0","January");    values.put("1","February");    values.put("2","March");    values.put("3","April");    values.put("4","May");    values.put("5","June");    values.put("6","July");    values.put("7","August");    values.put("8","September");    values.put("9","October");    values.put("10","November");    values.put("11","December");      wdContext.currentContextElement().setMonthName("10");

 

If you bind the selectedKeyproperty of a radio button group to a context attribute that is not defined as a root node attribute, you must observe the cardinality of the associated context node when implementing the above source text (see example B).

3. Binding the Example Context to a Radio Button Group

You can bind a UI element that allows key binding to this context (in this case, the RadioButtonGroupByKey UI element) by assigning the context path to a radio button group at design time or by dynamically binding the radio button group to the above mentioned example context at runtime and generating it. You can use the wdDoModifyView method in the controller implementation provided by Web Dynpro.

Controller implementation for dynamic generation of a radio button group:

public static void wdDoModifyView(IPrivateMainView wdThis, IPrivateMainView.IContextNode wdContext, com.sap.tc.webdynpro.progmodel.api.IWDView view, boolean firstTime)   {     //@@begin wdDoModifyView         if (firstTime)         {         IWDRadioButtonGroupByKey radioButtonGroup =(IWDRadioButtonGroupByKey)         view.createElement(IWDRadioButtonGroupByKey.class, "MyRadioButtonGroupByKey");         radioButtonGroup.bindSelectedKey("MonthName");         radioButtonGroup.setColCount(3);         IWDTransparentContainer container=(IWDTransparentContainer)         view.getElement("RootUIElementContainer");         container.addChild(radioButtonGroup);       }      //@@end   }

Example B

1. Defining the Context at Design Time (Creating a Context Attribute as a Context Attribute of the NodeX Node):

Value node NodeX Value attribute "MonthName”, type=”String”.

2. Initializing Node Elements in the wdDolnit Method:

If the cardinality of the NodeX node has been declared with O..n or O..1, there is no node element at runtime, therefore the system must generate a node element in the controller implementation.

//Get access to data type instance to be modified at runtime public void wdDoInit()   {       IPrivateMainView.INodeXElement newElement = wdContext.createNodeXElement();       ISimpleTypeModifiable myType=wdThis.wdGetAPI().getContext().getModifiableTypeOf("NodeX.MonthName");       IModifiableSimpleValueSet values=myType.getSVServices().getModifiableSimpleValueSet();             values.put("0","January");             values.put("1","February");             values.put("2","March");             values.put("3","April");             values.put("4","May");             values.put("5","June");             values.put("6","July");             values.put("7","August");             values.put("8","September");             values.put("9","October");             values.put("10","November");             values.put("11","December");       wdContext.nodeNodeX().addElement(newElement);       wdContext.currentNodeXElement().setMonthName("0");    wdContext.currentRadioButtonsElement().setMonthName("10");    */     //@@end   }

If the cardinality of the NodeX node has been declared with 1..n or 1..1, a node element is present at runtime and you can use the controller implementation in example A, however, you must specify the exact path of the context attribute as a parameter of the getModifiableTypeOf method:

ISimpleTypeModifiable myType=wdThis.wdGetAPI().getContext().getModifiableTypeOf("NodeX.MonthName");

3. Binding the Context Example to a Radio Button Group

See example A

However, even in this case an exact description of the context attribute path is required:

radioButtonGroup.bindSelectedKey("NodeX.MonthName");

4. Result

In both cases, the user sees a radio button group over three columns with the names of the months: