I have a datagrid, containing three columns defined in the MXML.
I am also adding some columns dynamically to the datagrid, depending on the data retrieved.
Initially, I set the original columns to an array in the initialize event of the application:
private var _origColumns:Array();
private function appInit() :void
{
_origColumns = new Array();
_origColumns = myDataGrid.columns;
}
And when I invoke the function to add columns, I want to restore first the datagrid to its original set of columns
private function addCols() :void
{
var columnToAdd:Array = new Array();
columnToAdd = _origColumns;
// Add the new columns to the columnToAdd Array.
//
//
myDataGrid.columns = columnToAdd;
}
The problem I have is that, when I invoke the function addCols, those columns that were added also remains, even though I am trying to revert back the new array of columns to be added to the _origColumns array. Basically I am ending up with the other columns originally added, plus the new columns that were just added.开发者_C百科 I would like to revert to the first three columns first, then just add over the columns which I want to add.
I checked the _origColumns variable and it seems to be growing when the columns have already been added to the datagrid, although I am not re-assigning it to the value of the datagrid columns.
I hope someone can provide more insight on why this is happening. Been banging my head for the last couple of hours on this.
I tried to add a changewatcher utility to the array _origColumns but it seems it is being changed but the watch event is not dispatching.
Thanks,
It is because in your appInit function, you have overwritten _origColumns with the same underlying array object from the datagrid. So whenever a column is added to the datagrid, by default it is being added to your _origColumns array.
private function appInit() :void
{
_origColumns = new Array();
_origColumns = myDataGrid.columns; // Offending line
// both properties will reference the same underlying Array object
}
A quick fix would be to make a copy of the array, you can do so using the Array.concat method (I'll assume at least Flex 3). Change the offending line to:
_origColumns = myDataGrid.columns.concat(); // passing no arguments makes a shallow copy
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