Flex GoodNess : How to bind TextInput data to a VO behind

Recently , I was looking for a way to update the VO(Value Object) when the TextInput value changes.

With Flex4, We can use Two way binding (usage: @{ } )

With Flex3, We can use the ValueCommit event to update the backend VO.

Value commit event gets fired when the TextInput control value changes through UI interaction or programmitically.

   1: //if we have a datagrid name dg, then a two way binding will look like this, Note: @ symbol is the main one

   2: <s:TextInput text="@{dg.selectedItem.name}"/> 

   3:  

   4: //Also if its Flex 3 ,where two way binding is not available, we can use the value commit event, to update the value ourself

5: <mx:TextInput id="txInput2" text="{dg.selectedItem.email}" valueCommit="txInput2_valueCommitHandler(event)"/>

Enjoy FLexing!!

Flex Goodness : NaN and Number

In flex, instead of using primitive datatypes like ent it is recommented Number datatype which supports double precision point floating number.

When a Number is not initialized, its value is NaN (Not a Number). Following are some methods which can be used to explore more about Number.

   1: var num:Number //this assigns a NaN value to it

   2: trace isNaN(num) //prints true

   3: trace int(num) //converts number to int and prints 0

   4: trace uint(num) //coverts number to uint   5:  

   6: var iStr:String = "1000"

   7: var convNum:Number = parseInt(iStr) //converts String to Number

   8: var convNumFloat:Number = parseFloat(iStr) //converts String to a float number

Enjoy Flexing!!

Flex Actionscript Goodness : Finding and Removing a Object from ArrayCollection(IViewCursor and Sort)

There is always a need to find a particular object or remove it from the ArrayCollection class based on a various member variable conditions.

IViewCursor and Sort classes of mx.collections are a perfect fit for it

Goal: Find employee by empId and remove it

Step1 : Lets Create a ArrayCollection of two Employees

   1: public class EmployeeVo{

   2:     var empNo:String

   3:     var firstName:String

   4:     var lastName:String

   5: }

   6:  

   7: var empVo1:EmployeeVo = new EmployeeVo()

   8: empVo1.empNo=1

   9: empVo1.firstName="john"

  10: empVo1.lastName="tyson"

  11:  

  12: var empVo2:EmployeeVo = new EmployeeVo()

  13: empVo2.empNo=2

  14: empVo2.firstName="ram"

  15: empVo2.lastName="balram"

  16:  

  17: var empCol:ArrayCollection = new ArrayCollection()

  18: empCol.addItem(empVo1)

  19: empCol.addItem(empVo2)

  20:  

  21:  

  22:  

  23:  

Step2 : Sort the employee Vo Class by empId And Find it / Remove it

Note: Sort it needed first in order to use the IViewCursor

   1: import mx.collections.IViewCursor

   2: import mx.collections.Sort

   3: pubic function findAndDeleteEmp(empId:String):void{    

   4:    addSort()

   5:    var cursor:IViewCursor = empCol.createCursor()

   6:    var searchEmpVo:EmployeeVo = new EmployeeVo()

   7:    searchEmpVo.empId = empId

   8:    var isExisting:Boolean = cursor.findAny(searchEmpVo)

   9:    if(isExisting){

  10:        //to get the found object

  11:        var foundEmpVo:EmployeeVo = cursor.currentItem as EmployeeVo

  12:        //to remove the found object

  13:        var deletedObj:EmployeeVo =cursor.remove() as EmployeeVo

  14:    }

  15: }

  16:  

  17: public function addSort():void{

  18:    //Add Sorting to Array Collection

  19:     var fieldName:String = "empId"

  20:     var sortField:SortField = new SortField(fieldName, true,descending);

  21:     var sort:Sort = new Sort();

  22:     sort.fields = new Array(sortField)    

  23:     empCol.sort = sort

  24:     empCol.refresh()

  25: }

Step3: Done!! Hurray!!!