In a MultiLine textbox when a large amount of text is put into, a scrollbar appears if the scrollbar property has been set to vertical. But by default the scrollbar maintains its position at top no matter how long the text content is. If you want to programmatically keep the scrollbar down to the last entered text , then use the SelectionStart and ScrollToCaret(). They are found in the namespace System.Windows.Forms
It gets/sets a character index for the begining of the current selection.
In case the specified selection ends between a carriage return and a new-line character, the selection length is automatically increased by 1 to span the end-of-line marker.
If there is no selection, the SelectionStart value gets or sets the location of the cursor.
It scrolls the content of the control to the current caret position i:e until the caret is with in the visible region of the control.