/// <summary>
/// Moves one endpoint of the range the specified number of units in the text.
/// If the endpoint being moved crosses the other endpoint then the other endpoint
/// is moved along too resulting in a degenerate range and ensuring the correct ordering
/// of the endpoints. (i.e. always Start<=End)
/// </summary>
/// <param name="endpoint">The endpoint to move.</param>
/// <param name="unit">The textual unit for moving.</param>
/// <param name="count">The number of units to move. A positive count moves the endpoint forward.
/// A negative count moves backward. A count of 0 has no effect.</param>
/// <returns>The number of units actually moved, which can be less than the number requested if
/// moving the endpoint runs into the beginning or end of the document.</returns>
public int MoveEndpointByUnit(TextPatternRangeEndpoint endpoint, TextUnit unit, int count)
{
ValidateEndpointArgument(endpoint, "endpoint");
ValidateUnitArgument(unit, "unit");
return(UiaCoreApi.TextRange_MoveEndpointByUnit(_hTextRange, endpoint, unit, count));
}