public bool TryMoveUp(Rect rect)
{
if (_screenDataRowIndex < AxisYConverter.ToData(_startPoint.Y)) // 不在位置 0 (第一笔)
{
_startPoint = new Point(rect.X, rect.Y <= 0 ? 0 : rect.Y - rect.Height);
_currentPoint = new Point(rect.X + rect.Width, _startPoint.Y);
return(true);
}
return(false);
}
protected override void OnParentKeyDown(object sender, KeyEventArgs e)
{
if (Keyboard.Modifiers == ModifierKeys.Shift)
{
return;
}
if (InitalDrawLocation == null)
{
return;
}
_screenDataRowIndex = AxisPanel.GetScreenTopRowIndex();
var prevRowIndex = AxisYConverter.ToData(InitalDrawLocation.Value.Y);
switch (e.Key)
{
case Key.Left:
MoveLeft(InitalDrawLocation.Value);
MeasureDragingArea(_screenDataRowIndex);
e.Handled = 0 <= ConvertToRelativePosition(_startPoint).X;
break;
case Key.Right:
if (TryMoveRight(InitalDrawLocation.Value))
{
MeasureDragingArea(_screenDataRowIndex);
}
e.Handled = ConvertToRelativePosition(_currentPoint).X <= RenderSize.Width;
break;
case Key.Up:
TryMoveUp(InitalDrawLocation.Value);
var moveUpRowIndex = AxisYConverter.ToData(_startPoint.Y);
e.Handled = moveUpRowIndex != prevRowIndex;
if (!e.Handled)
{
_screenDataRowIndex -= _screenDataRowIndex > 0 ? 1 : 0; // scroll up occurred
}
MeasureDragingArea(_screenDataRowIndex);
break;
case Key.Down:
TryMoveDown(InitalDrawLocation.Value);
var moveDownRowIndex = AxisYConverter.ToData(_startPoint.Y);
if ((RenderSize.Height - AxisYConverter.DataToScreen(moveDownRowIndex)) < Interval) // 屏幕最后一格未满
{
e.Handled = false;
}
else
{
e.Handled = moveDownRowIndex != prevRowIndex;
}
MeasureDragingArea(_screenDataRowIndex);
if (!e.Handled)
{
_screenDataRowIndex += GetItemsSourceCount() - 1 <= moveDownRowIndex ? 0 : 1; // scroll down occurred
}
break;
default:
ClickCount = 0;
break;
}
SetInitalDrawLocation();
if (e.Handled)
{
InvalidateVisual(); //未发生scroll bar 卷动, 手动刷新 cell 新的位置
}
else
{
LayerContainer.Focus();
}
// e.Handled 如果为 false 代表由 scroll bar 滚动来引发重绘
}