how to query with combobox with Flex

SpencerTrevor

Hi there,

Is there any sample that I can refer to make a Query using Combobox in Flex? I am very new in Flex so any help will do.

Thank you in advance

DanJensen

Spencer and Alexander,

There are, of course, two stages. 

1. Populate the combobox with items from a layer during application intialization.
2. Use the user selected item to query agains that layer

One problem with step one that I had was that the items in the layer were not unique, but I needed to provide a unique list for the user.  First I did a query to return all records in the layer.  Then I filtered that returned dataset for unique values of the field I wanted to use to populate the control.  The code below shows how I filtered the data.  I actually used a drop down list control, but the process is the same.

private function onDDLInitComplete(fSet:FeatureSet, token:Object=null):void
   {
    //defines and sorts a unique list of values for the drop down list control
    //Populates the bindable application variable ddlValuesAC
    var i:int = 1;
    var item:String;
    var sortAttr:Array=fSet.attributes.sortOn("FieldName");
    for (var j:int=0; j<fSet.attributes.length-1; j++)
    {
     item = sortAttr.FieldName;
     //getItemIndex returns -1 it item is not found in the array
     i=ddlValuesAC.getItemIndex(item);
     if (i==-1){
      ddlValuesAC.addItem(item);
     }
    }
   }

Now that I have a drop down list with just the unique values from the layer, I can return one to many records depending on the user's selection.  Code example below.

protected function ddlControl_changeHandler(event:IndexChangeEvent):void
   {
    mapQuery.where="fieldName = '" + ddlControl.selectedItem + "'";
    mapQuery.geometry = null;  //this in case geometry was used in previous query
    mapQueryTask.execute(mapQuery, new AsyncResponder(onQueryExecuteComplete, onFault));
   }

You will use the onQueryExecuteCompleteFunction to display the data to the user in the manner that meets your application requirements.  Likely you will use the results to populate a variable that is bound to the dataProvider attribute of a dataGrid control.

Good Luck,
-Dan