This method first checks the current value of the ChildControlsCreated property. If this value is false, the CreateChildControls method is called.
The EnsureChildControls method is typically used in composite controls, which are controls that use child controls for some or all their functionality. The EnsureChildControls method is called in order to make sure that child controls have been created and are ready to process input, to perform data binding, or to perform other tasks.
The GridView control is an example of a composite control. It creates child controls such as Table, TableRow, TableCell, Label, and TextBox controls, which are used to render the HTML table that the GridView generates.
In most cases, custom server control developers do not have to override this method. If you do override this method, use it in a way similar to the default behavior.