A list-like data structure that can be used with the [class@Gtk.
TreeView].
The `GtkListStore` object is a list model for use with a `GtkTreeView` widget. It implements the `GtkTreeModel` interface, and
consequentialy, can use all of the methods available there. It also implements the `GtkTreeSortable` interface so it can be sorted by the
view. Finally, it also implements the tree [drag](iface.TreeDragSource.html) and [drop](iface.TreeDragDest.html) interfaces.
The `GtkListStore` can accept most `GType`s as a column type, though it can’t accept all custom types. Internally, it will keep a copy
of data passed in (such as a string or a boxed pointer). Columns that accept `GObject`s are handled a little differently. The
`GtkListStore` will keep a reference to the object instead of copying the value. As a result, if the object is modified, it is up to the
application writer to call [[email protected]_changed] to emit the [[email protected]:GtkListStore:row_changed]
signal. This most commonly affects lists with [[email protected]]s stored.
An example for creating a simple list store:
```c enum { COLUMN_STRING, COLUMN_INT, COLUMN_BOOLEAN, N_COLUMNS };
{ GtkListStore *list_store; GtkTreePath *path; GtkTreeIter iter; int i;
list_store = gtk_list_store_new (N_COLUMNS, G_TYPE_STRING, G_TYPE_INT, G_TYPE_BOOLEAN);
for (i = 0; i < 10; i++) { char *some_data;
some_data = get_some_data (i);
// Add a new row to the model gtk_list_store_append (list_store, &iter); gtk_list_store_set (list_store, &iter, COLUMN_STRING,
some_data, COLUMN_INT, i, COLUMN_BOOLEAN, FALSE, -1);
// As the store will keep a copy of the string internally, // we free some_data. g_free (some_data); }
// Modify a particular row path = gtk_tree_path_new_from_string ("4"); gtk_tree_model_get_iter (GTK_TREE_MODEL (list_store), &
iter, path); gtk_tree_path_free (path); gtk_list_store_set (list_store, &iter, COLUMN_BOOLEAN, TRUE, -1); } ```
Performance Considerations
Internally, the `GtkListStore` was originally implemented with a linked list with a tail pointer. As a result, it was fast at data
insertion and deletion, and not fast at random data access. The `GtkListStore` sets the `GTK_TREE_MODEL_ITERS_PERSIST` flag, which means
that `GtkTreeIter`s can be cached while the row exists. Thus, if access to a particular row is needed often and your code is expected to
run on older versions of GTK, it is worth keeping the iter around.
Atomic Operations
It is important to note that only the methods insert_with_values and
insert_with_valuesv are atomic, in the sense that the row is being
appended to the store and the values filled in in a single operation with regard to `GtkTreeModel` signaling. In contrast, using e.g.
append and then @set will
first create a row, which triggers the `GtkTreeModel:GtkListStore:row-inserted` signal on `GtkListStore`. The row, however,
is still empty, and any signal handler connecting to `GtkTreeModel:GtkListStore:row-inserted` on this particular store should
be prepared for the situation that the row might be empty. This is especially important if you are wrapping the `GtkListStore` inside a
`GtkTreeModel`Filter and are using a `GtkTreeModel`FilterVisibleFunc. Using any of the non-atomic operations to append rows to the
`GtkListStore` will cause the `GtkTreeModel`FilterVisibleFunc to be visited with an empty row first; the function must be prepared for
that.
GtkListStore as GtkBuildable
The GtkListStore implementation of the [[email protected]] interface allows to specify the model columns with a `<columns>`
element that may contain multiple `<column>` elements, each specifying one model column. The “type” attribute specifies the data
type for the column.
Additionally, it is possible to specify content for the list store in the UI definition, with the `<data>` element. It can contain
multiple `<row>` elements, each specifying to content for one row of the list model. Inside a `<row>`, the `<col>`
elements specify the content for individual cells.
Note that it is probably more common to define your models in the code, and one might consider it a layering violation to specify the
content of a list store in a UI definition, data, not presentation, and common wisdom is to separate the two, as far as possible.
An example of a UI Definition fragment for a list store:
```xml <object class="GtkListStore"> <columns> <column type="gchararray"/> <column type="gchararray"/> <
column type="gint"/> </columns> <data> <row> <col id="0">John</col> <col id="1">Doe</col
> <col id="2">25</col> </row> <row> <col id="0">Johan</col> <col id="1">Dahlin</col
> <col id="2">50</col> </row> </data> </object> ```