Gtk.TreeModelSort
Description: Reference for Gtk.TreeModelSort

### Class

# GtkTreeModelSort

#### Description [src]

    class Gtk.TreeModelSort : GObject.Object {
      parent: GObject
    }

A GtkTreeModel which makes an underlying tree model sortable

The `GtkTreeModelSort` is a model which implements the `GtkTreeSortable` interface. It does not hold any data itself, but rather is created with a child model and proxies its data. It has identical column types to this child model, and the changes in the child are propagated. The primary purpose of this model is to provide a way to sort a different model without modifying it. Note that the sort function used by `GtkTreeModelSort` is not guaranteed to be stable.

The use of this is best demonstrated through an example. In the following sample code we create two `GtkTreeView` widgets each with a view of the same data. As the model is wrapped here by a `GtkTreeModelSort`, the two `GtkTreeView`s can each sort their view of the data without affecting the other. By contrast, if we simply put the same model in each widget, then sorting the first would sort the second.

## Using a `GtkTreeModelSort`

    {
      GtkTreeView *tree_view1;
      GtkTreeView *tree_view2;
      GtkTreeModel *sort_model1;
      GtkTreeModel *sort_model2;
      GtkTreeModel *child_model;

      // get the child model
      child_model = get_my_model ();

      // Create the first tree
      sort_model1 = gtk_tree_model_sort_new_with_model (child_model);
      tree_view1 = gtk_tree_view_new_with_model (sort_model1);

      // Create the second tree
      sort_model2 = gtk_tree_model_sort_new_with_model (child_model);
      tree_view2 = gtk_tree_view_new_with_model (sort_model2);

      // Now we can sort the two models independently
      gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (sort_model1),
                                            COLUMN_1, GTK_SORT_ASCENDING);
      gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (sort_model2),
                                            COLUMN_1, GTK_SORT_DESCENDING);
    }

To demonstrate how to access the underlying child model from the sort model, the next example will be a callback for the `GtkTreeSelection` `GtkTreeSelection::changed` signal. In this callback, we get a string from COLUMN_1 of the model. We then modify the string, find the same selected row on the child model, and change the row there.

## Accessing the child model of in a selection changed callback

    void
    selection_changed (GtkTreeSelection *selection, gpointer data)
    {
      GtkTreeModel *sort_model = NULL;
      GtkTreeModel *child_model;
      GtkTreeIter sort_iter;
      GtkTreeIter child_iter;
      char *some_data = NULL;
      char *modified_data;

      // Get the current selected row and the model.
      if (! gtk_tree_selection_get_selected (selection,
                                             &sort_model,
                                             &sort_iter))
        return;

      // Look up the current value on the selected row and get
      // a new value to change it to.
      gtk_tree_model_get (GTK_TREE_MODEL (sort_model), &sort_iter,
                          COLUMN_1, &some_data,
                          -1);

      modified_data = change_the_data (some_data);
      g_free (some_data);

      // Get an iterator on the child model, instead of the sort model.
      gtk_tree_model_sort_convert_iter_to_child_iter (GTK_TREE_MODEL_SORT (sort_model),
                                                      &child_iter,
                                                      &sort_iter);

      // Get the child model and change the value of the row. In this
      // example, the child model is a GtkListStore. It could be any other
      // type of model, though.
      child_model = gtk_tree_model_sort_get_model (GTK_TREE_MODEL_SORT (sort_model));
      gtk_list_store_set (GTK_LIST_STORE (child_model), &child_iter,
                          COLUMN_1, &modified_data,
                          -1);
      g_free (modified_data);
    }

#### Ancestors

- GObject

#### Implements

- GtkTreeDragSource
- GtkTreeModel
- GtkTreeSortable

#### Constructors

###### gtk_tree_model_sort_new_with_model

Creates a new `GtkTreeModelSort`, with `child_model` as the child model.

#### Instance methods

###### gtk_tree_model_sort_clear_cache

This function should almost never be called. It clears the `tree_model_sort` of any cached iterators that haven’t been reffed with gtk_tree_model_ref_node(). This might be useful if the child model being sorted is static (and doesn’t change often) and there has been a lot of unreffed access to nodes. As a side effect of this function, all unreffed iters will be invalid.

###### gtk_tree_model_sort_convert_child_iter_to_iter

Sets `sort_iter` to point to the row in `tree_model_sort` that corresponds to the row pointed at by `child_iter`. If `sort_iter` was not set, `FALSE` is returned. Note: a boolean is only returned since 2.14.

###### gtk_tree_model_sort_convert_child_path_to_path

Converts `child_path` to a path relative to `tree_model_sort`. That is, `child_path` points to a path in the child model. The returned path will point to the same row in the sorted model. If `child_path` isn’t a valid path on the child model, then `NULL` is returned.

###### gtk_tree_model_sort_convert_iter_to_child_iter

Sets `child_iter` to point to the row pointed to by `sorted_iter`.

###### gtk_tree_model_sort_convert_path_to_child_path

Converts `sorted_path` to a path on the child model of `tree_model_sort`. That is, `sorted_path` points to a location in `tree_model_sort`. The returned path will point to the same location in the model not being sorted. If `sorted_path` does not point to a location in the child model, `NULL` is returned.

###### gtk_tree_model_sort_get_model

Returns the model the `GtkTreeModelSort` is sorting.

###### gtk_tree_model_sort_iter_is_valid

> This function is slow. Only use it for debugging and/or testing purposes.

###### gtk_tree_model_sort_reset_default_sort_func

This resets the default sort function to be in the “unsorted” state. That is, it is in the same order as the child model. It will re-sort the model to be in the same order as the child model only if the `GtkTreeModelSort` is in “unsorted” state.

##### Methods inherited from GObject (43)

Please see GObject for a full list of methods.

##### Methods inherited from GtkTreeDragSource (3)

###### gtk_tree_drag_source_drag_data_delete

Asks the `GtkTreeDragSource` to delete the row at `path`, because it was moved somewhere else via drag-and-drop. Returns `FALSE` if the deletion fails because `path` no longer exists, or for some model-specific reason. Should robustly handle a `path` no longer found in the model!

###### gtk_tree_drag_source_drag_data_get

Asks the `GtkTreeDragSource` to return a `GdkContentProvider` representing the row at `path`. Should robustly handle a `path` no longer found in the model!

###### gtk_tree_drag_source_row_draggable

Asks the `GtkTreeDragSource` whether a particular row can be used as the source of a DND operation. If the source doesn’t implement this interface, the row is assumed draggable.

##### Methods inherited from GtkTreeModel (28)

Please see GtkTreeModel for a full list of methods.

##### Methods inherited from GtkTreeSortable (6)

###### gtk_tree_sortable_get_sort_column_id

Fills in `sort_column_id` and `order` with the current sort column and the order. It returns `TRUE` unless the `sort_column_id` is `GTK_TREE_SORTABLE_DEFAULT_SORT_COLUMN_ID` or `GTK_TREE_SORTABLE_UNSORTED_SORT_COLUMN_ID`.

###### gtk_tree_sortable_has_default_sort_func

Returns `TRUE` if the model has a default sort function. This is used primarily by GtkTreeViewColumns in order to determine if a model can go back to the default state, or not.

###### gtk_tree_sortable_set_default_sort_func

Sets the default comparison function used when sorting to be `sort_func`. If the current sort column id of `sortable` is `GTK_TREE_SORTABLE_DEFAULT_SORT_COLUMN_ID`, then the model will sort using this function.

###### gtk_tree_sortable_set_sort_column_id

Sets the current sort column to be `sort_column_id`. The `sortable` will resort itself to reflect this change, after emitting a `GtkTreeSortable::sort-column-changed` signal. `sort_column_id` may either be a regular column id, or one of the following special values:

###### gtk_tree_sortable_set_sort_func

Sets the comparison function used when sorting to be `sort_func`. If the current sort column id of `sortable` is the same as `sort_column_id`, then the model will sort using this function.

###### gtk_tree_sortable_sort_column_changed

Emits a `GtkTreeSortable::sort-column-changed` signal on `sortable`.

#### Properties

###### Gtk.TreeModelSort:model

No description available.

#### Signals

##### Signals inherited from GObject (1)

###### GObject.Object::notify

The notify signal is emitted on an object when one of its properties has its value set through g_object_set_property(), g_object_set(), et al.

##### Signals inherited from GtkTreeModel (5)

###### Gtk-4.0.TreeModel::row-changed

This signal is emitted when a row in the model has changed.

###### Gtk-4.0.TreeModel::row-deleted

This signal is emitted when a row has been deleted.

###### Gtk-4.0.TreeModel::row-has-child-toggled

This signal is emitted when a row has gotten the first child row or lost its last child row.

###### Gtk-4.0.TreeModel::row-inserted

This signal is emitted when a new row has been inserted in the model.

###### Gtk-4.0.TreeModel::rows-reordered

This signal is emitted when the children of a node in the `GtkTreeModel` have been reordered.

##### Signals inherited from GtkTreeSortable (1)

###### Gtk-4.0.TreeSortable::sort-column-changed

The ::sort-column-changed signal is emitted when the sort column or sort order of `sortable` is changed. The signal is emitted before the contents of `sortable` are resorted.

#### Class structure

    struct GtkTreeModelSortClass {
      GObjectClass parent_class;

    }

No description available.

###### Class members

`parent_class: GObjectClass`
  No description available.