Check mandatory dropdownbykey

Question

In my view I have two dropdownbykey elements. After a push on the button I want to check if a value in the dropdown is selected.
I found the following code to check "simple" inputfields:
public void checkMandatory( java.lang.String fieldname )
    //@@begin checkMandatory()
    IWDMessageManager msgMan = wdComponentAPI.getMessageManager();
    String value = wdContext.nodeProject().currentProjectElement().getAttributeAsText(fieldname);
    IWDAttributeInfo projectAttr = wdContext.nodeProject().getNodeInfo().getAttribute(fieldname);
    if (value.length() == 0) {
         msgMan.reportContextAttributeMessage(
              wdContext.nodeProject().currentProjectElement(),
              projectAttr,
              IMessageCCAdvice.MISSING_INPUT,
              new Object[] { fieldname },
              true);
    //@@end
But if I run this a dump appears on
String value = wdContext.nodeProject().currentProjectElement().getAttributeAsText(fieldname);
It works fine for "simple" inputfields but not for the dropdown fields.
Can anybody help me?
Thanks in advance.
Michael

Answer 1

Hi
Do dynamic validation this way, its generic for every string attribute, regardless of the UIElement..:
//Method on the view
public void checkMandatory( java.lang.String[] pathNodeNames, java.lang.String attributeName, java.lang.String placeHolder )
    //@@begin checkMandatory()
      //MessageManagerInstance
      IWDMessageManager messageManager =     wdComponentAPI.getMessageManager();
      IWDNode node = wdContext;
      Object attributeValue = null;
      IWDAttributeInfo attributeInfo = null;
      //Find the attribute within context tree
      if (pathNodeNames.length == 0)
           //Let's get the attribute value          
           attributeValue = wdContext.currentContextElement().getAttributeValue(attributeName);
      else
     for(int i=0; i< pathNodeNames.length; i++)
       //Go a level down within context tree
       node = node.getChildNode(pathNodeNames<i>, IWDNode.LEAD_SELECTION);
      //Let's get the attribute value          
      attributeValue = node.getCurrentElement().getAttributeValue(attributeName);
      //Extract attribute info
      attributeInfo = node.getNodeInfo().getAttribute(attributeName);
      //Check if the string is null or empty, and report nulls/empties to messagemanager
      if (isEmptyField(attributeValue))     
           messageManager.reportContextAttributeMessage(node.getCurrentElement(),
               attributeInfo, IMessageCCAdvice.MISSING_INPUT, new Object[] { placeHolder }, true);
    //@@end
  //Metodo on the view
public boolean isEmptyField( java.lang.Object attributeValue )
    //@@begin isEmptyField()
      String stringValue;
      if ((attributeValue != null))
           stringValue = attributeValue.toString();
           if (stringValue.trim().length() > 0)
             return false;
      return true;     
    //@@end
  //Method which will manage dynamic validation to achieve business rules
   public void doValidateFields( )
      if (someCondition())  //You can validate based on conditions, in order to apply business rules sucessfully
        //Array of Strings would go empty if the attribute is located in context root
        //wdContext -->attribute
        this.checkMandatory(new String[]{} , fieldname , "placeholderValue");
      else
        //Careful here, you'll send one element inside the array of String for each subnode in context tree in which attributeName is located
        //on your case, within context root you have a node called "Project", and your attributeName inside "Project"
        //wdContext-->node "Project"--> attribute "fieldName"
        checkMandatory(new String[]{"Project"}, "fieldName", "placeholder text of your choice if needed");
        //Show error messages if thats the case
           wdComponentAPI.getMessageManager().raisePendingException();
Just call the method doValidateFields whenever you want to apply dynamic validation.
  public void onActionRejectLoanRequest(com.sap.tc.webdynpro.progmodel.api.IWDCustomEvent wdEvent )
    //@@begin onActionRejectLoanRequest(ServerEvent)
     //Execute validations
     doValidateFields();
     //ATTENTION:  If at least one field didn't pass validation,
     //                    this Action's code will stop HERE, next lines
     //                    won't execute. Nice uh?
     //Call method of Loan Reject in CompController to execute reject actions
     wdThis.wdGetLoansAdministrationCompController().doRejectRequest();
    //@@end
Normally, i use some generic error message, and pass the name or description of the value i'm validating, something like:
"The value is mandatory, please select or enter a valid value".
It could be generic too (passed as parameter) , with a few more refinement of this method.
Regards
Julio C. Herrera Cuevas