Adding a 'change_selection' method which allows changed the selected row (or rows) in the grid.

Author: Tim Shawver

js/src/qgrid.widget.js

@@ -215,6 +215,7 @@ class QgridView extends widgets.DOMWidgetView {
     this.sort_in_progress = false;
     this.sort_indicator = null;
     this.resizing_column = false;
+    this.ignore_selection_changed = false;
 
     var number_type_info = {
       filter: slider_filter.SliderFilter,
@@ -342,6 +343,10 @@ class QgridView extends widgets.DOMWidgetView {
         delete slick_column.width;
       }
 
+      if (cur_column.maxWidth == null){
+        delete slick_column.maxWidth;
+      }
+
       // don't allow editing index columns
       if (cur_column.is_index) {
         slick_column.editor = editors.IndexEditor;
@@ -522,8 +527,10 @@ class QgridView extends widgets.DOMWidgetView {
     });
 
     this.slick_grid.onSelectedRowsChanged.subscribe((e, args) => {
-      var msg = {'rows': args.rows, 'type': 'change_selection'};
-      this.send(msg);
+      if (!this.ignore_selection_changed) {
+        var msg = {'rows': args.rows, 'type': 'change_selection'};
+        this.send(msg);
+      }
     });
 
     setTimeout(() => {
@@ -739,6 +746,13 @@ class QgridView extends widgets.DOMWidgetView {
         } else {
           this.slick_grid.setOptions({'editable': false});
         }
+    } else if (msg.type == 'change_selection') {
+        this.ignore_selection_changed = true;
+        this.slick_grid.setSelectedRows(msg.rows);
+        if (msg.rows && msg.rows.length > 0) {
+          this.slick_grid.scrollRowIntoView(msg.rows[0]);
+        }
+        this.ignore_selection_changed = false;
     } else if (msg.col_info) {
       var filter = this.filters[msg.col_info.name];
       filter.handle_msg(msg);

qgrid/grid.py

@@ -1396,19 +1396,7 @@ def _handle_qgrid_msg_helper(self, content):
                 })
                 return
         elif content['type'] == 'change_selection':
-            old_selection = self._selected_rows
-            self._selected_rows = content['rows']
-
-            # if the selection didn't change, just return without firing
-            # the event
-            if old_selection == self._selected_rows:
-                return
-
-            self._notify_listeners({
-                'name': 'selection_changed',
-                'old': old_selection,
-                'new': self._selected_rows
-            })
+            self._change_selection(content['rows'], 'gui')
         elif content['type'] == 'change_viewport':
             old_viewport_range = self._viewport_range
             self._viewport_range = (content['top'], content['bottom'])
@@ -1699,6 +1687,47 @@ def _remove_rows(self, rows=None):
         self._update_table(triggered_by='remove_row')
         return selected_names
 
+    def change_selection(self, rows=[]):
+        """
+        Select a row (or rows) in the UI.  The indices of the
+        rows to select are provided via the optional ``rows`` argument.
+
+        Parameters
+        ----------
+        rows : list (default: [])
+            A list of indices of the rows to select. For a multi-indexed
+            DataFrame, each index in the list should be a tuple, with each
+            value in each tuple corresponding to a level of the MultiIndex.
+            The default value of ``[]`` results in the no rows being
+            selected (i.e. it clears the selection).
+        """
+        new_selection = \
+            list(map(lambda x: self._df.index.get_loc(x), rows))
+
+        self._change_selection(new_selection, 'api', send_msg_to_js=True)
+
+    def _change_selection(self, rows, source, send_msg_to_js=False):
+        old_selection = self._selected_rows
+        self._selected_rows = rows
+
+        # if the selection didn't change, just return without firing
+        # the event
+        if old_selection == self._selected_rows:
+            return
+
+        if send_msg_to_js:
+            data_to_send = {
+                'type': 'change_selection',
+                'rows': rows
+            }
+            self.send(data_to_send)
+
+        self._notify_listeners({
+            'name': 'selection_changed',
+            'old': old_selection,
+            'new': self._selected_rows,
+            'source': source
+        })
 
 # Alias for legacy support, since we changed the capitalization
 QGridWidget = QgridWidget

qgrid/tests/test_grid.py

@@ -21,8 +21,8 @@ def create_df():
     })
 
 
-def create_large_df():
-    large_df = pd.DataFrame(np.random.randn(10000, 4), columns=list('ABCD'))
+def create_large_df(size=10000):
+    large_df = pd.DataFrame(np.random.randn(size, 4), columns=list('ABCD'))
     large_df['B (as str)'] = large_df['B'].map(lambda x: str(x))
     return large_df
 
@@ -179,7 +179,8 @@ def test_remove_row_button():
         {
             'name': 'selection_changed',
             'old': [],
-            'new': selected_rows
+            'new': selected_rows,
+            'source': 'gui'
         },
         {
             'name': 'row_removed',
@@ -679,29 +680,51 @@ def test_change_filter_viewport():
 
 
 def test_change_selection():
-    widget = QgridWidget(df=create_df())
+    widget = QgridWidget(df=create_large_df(size=10))
     event_history = init_event_history('selection_changed', widget=widget)
 
     widget._handle_qgrid_msg_helper({
         'type': 'change_selection',
         'rows': [5]
     })
+    assert widget._selected_rows == [5]
 
     widget._handle_qgrid_msg_helper({
         'type': 'change_selection',
         'rows': [7, 8]
     })
+    assert widget._selected_rows == [7, 8]
+
+    widget.change_selection([3, 5, 6])
+    assert widget._selected_rows == [3, 5, 6]
+
+    widget.change_selection()
+    assert widget._selected_rows == []
 
     assert event_history == [
         {
             'name': 'selection_changed',
             'old': [],
-            'new': [5]
+            'new': [5],
+            'source': 'gui'
         },
         {
             'name': 'selection_changed',
             'old': [5],
-            'new': [7, 8]
+            'new': [7, 8],
+            'source': 'gui'
+        },
+        {
+            'name': 'selection_changed',
+            'old': [7, 8],
+            'new': [3, 5, 6],
+            'source': 'api'
+        },
+        {
+            'name': 'selection_changed',
+            'old': [3, 5, 6],
+            'new': [],
+            'source': 'api'
         },
     ]