#794 - Add an event that exposes the internal selected row ids.

Make DataView. syncGridSelection() return an event that notifies when
an internal list of selected row ids changes.

1 files changed, 23 insertions, 4 deletions

diff --git a/slick.dataview.js b/slick.dataview.js
index 8103714..3c3d204 100644
--- a/slick.dataview.js
+++ b/slick.dataview.js
@@ -852,19 +852,36 @@
      * @param preserveHiddenOnSelectionChange {Boolean} Whether to keep selected items
      *     that are currently out of the view (see preserveHidden) as selected when selection
      *     changes.
+     * @return {Slick.Event} An event that notifies when an internal list of selected row ids
+     *     changes.  This is useful since, in combination with the above two options, it allows
+     *     access to the full list selected row ids, and not just the ones visible to the grid.
      * @method syncGridSelection
      */
     function syncGridSelection(grid, preserveHidden, preserveHiddenOnSelectionChange) {
       var self = this;
       var inHandler;
       var selectedRowIds = self.mapRowsToIds(grid.getSelectedRows());
+      var onSelectedRowIdsChanged = new Slick.Event();
+
+      function setSelectedRowIds(rowIds) {
+        if (selectedRowIds.join(",") == rowIds.join(",")) {
+          return;
+        }
+
+        selectedRowIds = rowIds;
+
+        onSelectedRowIdsChanged.notify({
+          "grid": grid,
+          "ids": selectedRowIds
+        }, new Slick.EventData(), self);
+      }
 
       function update() {
         if (selectedRowIds.length > 0) {
           inHandler = true;
           var selectedRows = self.mapIdsToRows(selectedRowIds);
           if (!preserveHidden) {
-            selectedRowIds = self.mapRowsToIds(selectedRows);
+            setSelectedRowIds(self.mapRowsToIds(selectedRows));       
           }
           grid.setSelectedRows(selectedRows);
           inHandler = false;
@@ -875,18 +892,20 @@
         if (inHandler) { return; }
         var newSelectedRowIds = self.mapRowsToIds(grid.getSelectedRows());
         if (!preserveHiddenOnSelectionChange || !grid.getOptions().multiSelect) {
-          selectedRowIds = newSelectedRowIds;
+          setSelectedRowIds(newSelectedRowIds);
         } else {
           // keep the ones that are hidden
-          selectedRowIds = $.grep(selectedRowIds, function(id) { return self.getRowById(id) === undefined; });
+          var existing = $.grep(selectedRowIds, function(id) { return self.getRowById(id) === undefined; });
           // add the newly selected ones
-          selectedRowIds = selectedRowIds.concat(newSelectedRowIds);
+          setSelectedRowIds(existing.concat(newSelectedRowIds));
         }
       });
 
       this.onRowsChanged.subscribe(update);
 
       this.onRowCountChanged.subscribe(update);
+
+      return onSelectedRowIdsChanged;
     }
 
     function syncGridCellCssStyles(grid, key) {