gtkTreeViewSetColumnDragFunction {RGtk2} | R Documentation

## gtkTreeViewSetColumnDragFunction

### Description

Sets a user function for determining where a column may be dropped when dragged. This function is called on every column pair in turn at the beginning of a column drag to determine where a drop can take place. The arguments passed to `func` are: the `tree.view`, the `GtkTreeViewColumn` being dragged, the two `GtkTreeViewColumn` s determining the drop spot, and `user.data`. If either of the `GtkTreeViewColumn` arguments for the drop spot are `NULL`, then they indicate an edge. If `func` is set to be `NULL`, then `tree.view` reverts to the default behavior of allowing all columns to be dropped everywhere.

### Usage

    gtkTreeViewSetColumnDragFunction(object, func, user.data = NULL)

### Arguments

``object`` | A `GtkTreeView`.
``func`` | A function to determine which columns are reorderable, or `NULL`. [ allow-none ]
``user.data`` | User data to be passed to `func`, or `NULL`. [ allow-none ]

### Author(s)

Derived by RGtkGen from GTK+ documentation

[Package RGtk2 version 2.20.36.3 Index]