## GtkTreeModelSort

GtkTreeModelSort — A GtkTreeModel which makes an underlying tree model sortable

## Synopsis

    #include <gtk/gtk.h>

    struct      GtkTreeModelSort;
    GtkTreeModel* gtk_tree_model_sort_new_with_model
                                                (GtkTreeModel *child_model);
    GtkTreeModel* gtk_tree_model_sort_get_model (GtkTreeModelSort *tree_model);
    GtkTreePath* gtk_tree_model_sort_convert_child_path_to_path
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreePath *child_path);
    void        gtk_tree_model_sort_convert_child_iter_to_iter
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreeIter *sort_iter,
                                                 GtkTreeIter *child_iter);
    GtkTreePath* gtk_tree_model_sort_convert_path_to_child_path
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreePath *sorted_path);
    void        gtk_tree_model_sort_convert_iter_to_child_iter
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreeIter *child_iter,
                                                 GtkTreeIter *sorted_iter);
    void        gtk_tree_model_sort_reset_default_sort_func
                                                (GtkTreeModelSort *tree_model_sort);
    void        gtk_tree_model_sort_clear_cache (GtkTreeModelSort *tree_model_sort);
    gboolean    gtk_tree_model_sort_iter_is_valid
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreeIter *iter);

## Object Hierarchy

      GObject
       +----GtkTreeModelSort

## Implemented Interfaces

GtkTreeModelSort implements GtkTreeModel, GtkTreeDragSource and GtkTreeSortable.

## Properties

      "model"                GtkTreeModel         : Read / Write / Construct Only

## Description

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.

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 GtkTreeViews 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.

Example 3. 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 "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.

Example 4. 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);
    }

## Details

### struct GtkTreeModelSort

    struct GtkTreeModelSort;

This should not be accessed directly. Use the accessor functions below.

### gtk_tree_model_sort_new_with_model ()

    GtkTreeModel* gtk_tree_model_sort_new_with_model
                                                (GtkTreeModel *child_model);

Creates a new GtkTreeModel, with `child_model` as the child_model.

`child_model` : | A GtkTreeModel
Returns : | A new GtkTreeModel.

### gtk_tree_model_sort_get_model ()

    GtkTreeModel* gtk_tree_model_sort_get_model (GtkTreeModelSort *tree_model);

Returns the model the GtkTreeModelSort is sorting.

`tree_model` : | a GtkTreeModelSort
Returns : | the "child model" being sorted

### gtk_tree_model_sort_convert_child_path_to_path ()

    GtkTreePath* gtk_tree_model_sort_convert_child_path_to_path
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreePath *child_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.

`tree_model_sort` : | A GtkTreeModelSort
`child_path` : | A GtkTreePath to convert
Returns : | A newly allocated GtkTreePath, or `NULL`

### gtk_tree_model_sort_convert_child_iter_to_iter ()

    void        gtk_tree_model_sort_convert_child_iter_to_iter
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreeIter *sort_iter,
                                                 GtkTreeIter *child_iter);

Sets `sort_iter` to point to the row in `tree_model_sort` that corresponds to the row pointed at by `child_iter`.

`tree_model_sort` : | A GtkTreeModelSort
`sort_iter` : | An uninitialized GtkTreeIter.
`child_iter` : | A valid GtkTreeIter pointing to a row on the child model

### gtk_tree_model_sort_convert_path_to_child_path ()

    GtkTreePath* gtk_tree_model_sort_convert_path_to_child_path
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreePath *sorted_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.

`tree_model_sort` : | A GtkTreeModelSort
`sorted_path` : | A GtkTreePath to convert
Returns : | A newly allocated GtkTreePath, or `NULL`

### gtk_tree_model_sort_convert_iter_to_child_iter ()

    void        gtk_tree_model_sort_convert_iter_to_child_iter
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreeIter *child_iter,
                                                 GtkTreeIter *sorted_iter);

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

`tree_model_sort` : | A GtkTreeModelSort
`child_iter` : | An uninitialized GtkTreeIter
`sorted_iter` : | A valid GtkTreeIter pointing to a row on `tree_model_sort`.

### gtk_tree_model_sort_reset_default_sort_func ()

    void        gtk_tree_model_sort_reset_default_sort_func
                                                (GtkTreeModelSort *tree_model_sort);

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.

`tree_model_sort` : | A GtkTreeModelSort

### gtk_tree_model_sort_clear_cache ()

    void        gtk_tree_model_sort_clear_cache (GtkTreeModelSort *tree_model_sort);

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.

`tree_model_sort` : | A GtkTreeModelSort

### gtk_tree_model_sort_iter_is_valid ()

    gboolean    gtk_tree_model_sort_iter_is_valid
                                                (GtkTreeModelSort *tree_model_sort,
                                                 GtkTreeIter *iter);

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

Checks if the given iter is a valid iter for this GtkTreeModelSort.

`tree_model_sort` : | A GtkTreeModelSort.
`iter` : | A GtkTreeIter.
Returns : | `TRUE` if the iter is valid, `FALSE` if the iter is invalid.

Since 2.2

## Properties

"`model`" (GtkTreeModel : Read / Write / Construct Only) | The model for the TreeModelSort to sort.

## See Also

GtkTreeModel, GtkListStore, GtkTreeStore, GtkTreeSortable, GtkTreeModelFilter