topic Re: dynamically change the fields shown in a datagrid in ArcGIS API for Flex Questions

dynamically change the fields shown in a datagrid

TracySchloss — Wed, 01 Feb 2012 20:55:00 GMT

I have a map services with many fields. There are logical names to the fields like "Pasture_2002_Acres", Pasture_2007_Acres", "Crops_2002_Acres", "Crops_2007_Acres"

I created an array of fields that I'd like to have show up in a datagrid. Based on whether the user wants to see Pasture information vs Crop information, the fields you'd want to see would be different.

I've run a querytask that generates a graphics layer and it contains all the attributes. If the user wants to see just Pasture information, I made an array of just the fields related to that. These become the fieldnames for a newly creaed datagrid. The year is set from a radio button. The results is an ArrayCollection I populated during the OnResults function of the querytask and it does have the right data in it.

   var fieldNameArray:Array = ["COUNTY","SQMILES",year+"_PASTURE_ACRES",year+"_PASTURE_SQMILES_TREATED",year+"_ PCTAREA_PASTURE"]; var selectDGcolumns:Array = [];    for each (var fieldName:String in fieldNameArray) {     var dgColumn:DataGridColumn = new DataGridColumn;     dgColumn.dataField = fieldName;     trace (dgColumn.dataField);     dgColumn.setStyle("textAlign","right");     selectDGcolumns.push(dgColumn);     }    dg.columns = selectDGcolumns;    dg.dataProvider = results;

This works just great the first time around. I have an "Open Table" button that opens a titleWindow that displays the datagrid. The grid populates with the fields and values I expect. The problem comes in when I want to change to a different subject.

The field array traces just fine (shows the change in the year).But when I go back through the 'for each' loop, the columns in the datagrid continue to be the ones I had chosen from the first time I used the tool. I think I have emptied the array out by maybe I'm not understanding how to empty out all my arrays etc properly.

Re: dynamically change the fields shown in a datagrid

RobertScheitlin__GISP — Sun, 12 Dec 2021 00:09:58 GMT

Tracy,

Try this:

            dg.dataProvider.removeAll();
            dg.columns = [];
            var fieldNameArray:Array = ["COUNTY","SQMILES",year+"_PASTURE_ACRES",year+"_PASTURE_SQMILES_TREATED",year+"_ PCTAREA_PASTURE"];
            var selectDGcolumns:Array = [];
            for each (var fieldName:String in fieldNameArray) {
                var dgColumn:DataGridColumn = new DataGridColumn;
                dgColumn.dataField = fieldName;
                trace (dgColumn.dataField);
                dgColumn.setStyle("textAlign","right");
                selectDGcolumns.push(dgColumn);    
            }
            dg.columns = selectDGcolumns;
            dg.dataProvider = results;

Re: dynamically change the fields shown in a datagrid

TracySchloss — Thu, 02 Feb 2012 13:41:00 GMT

There is no 'removeAll' option on the data provider. The dg.columns = []; sounded promising. But no go!

I have the datagrid as a separate custom component (it has listeners etc back to the graphicslayer) and the titlewindow is also custom.

I'm making a new datagrid each time

var dg:Fields_DataGrid = new Fields_DataGrid;

but the titlewindow was a variable set at the top. This turned out to be the problem, I needed to create a new one. (You'd think I would have seen a bunch of datagrid all getting added to the same titlewindow, but it didn't work out that way!)

Thanks for your assistance, I need an extra pair of eyes, and I don't have anyone around me to ask!