In this demo, resizing feature is enabled by setting the AllowResizing property as true and Task Name column can be resized between the range of minWidth (120px) and maxWidth (300px). Also, column resizing has been disabled for Duration column.
The Tree Grid columns can be resized by clicking and dragging at the right edge of columns header. Set AllowResizing property as true, to enable column resizing behavior in Tree Grid. You can also prevent the resize of the specific column by setting Columns->AllowResizing as false in columns definition.
More information on the data binding can be found in this documentation section.