我有一个简单的测试应用程序,其中包含一个基本的自定义
请问是否有人能够建议我是否可能实现这个功能,如果可以的话,我应该怎么做才能做对。我可以在SetHorizontalOffset中重新渲染绘图可视化对象,但由于我已经绘制了所有需要的东西,因此不希望这样做以提高性能。
希望问题有一定的意义 - 如果没有,请告诉我,我可以澄清。
非常感谢 - Karl
FrameworkElement
实现(下面是TestElement)。TestElement创建了几个绘图可视化对象,并在构造函数中绘制了一些东西,宽度为600。它还实现了IScrollinfo的必要部分; 包含该元素的窗口具有scrollviewer和最大尺寸为300x300。滚动条出现了,但无法滚动TestElement的内容。请问是否有人能够建议我是否可能实现这个功能,如果可以的话,我应该怎么做才能做对。我可以在SetHorizontalOffset中重新渲染绘图可视化对象,但由于我已经绘制了所有需要的东西,因此不希望这样做以提高性能。
希望问题有一定的意义 - 如果没有,请告诉我,我可以澄清。
非常感谢 - Karl
public class TestElement : FrameworkElement, IScrollInfo
{
DrawingVisual visual;
DrawingVisual visual2;
public TestElement()
{
Draw();
this.MaxWidth = 600;
this.MaxHeight = 300;
}
public void Draw()
{
if(visual == null)
{
visual = new DrawingVisual();
base.AddVisualChild(visual);
base.AddLogicalChild(visual);
}
if (visual2 == null)
{
visual2 = new DrawingVisual();
base.AddVisualChild(visual2);
base.AddLogicalChild(visual2);
}
Random rand = new Random();
var pen = new Pen(Brushes.Black, 1);
using(var dc = visual.RenderOpen())
{
for (int i = 0; i < 400; i++)
{
var r = rand.Next(10, 200);
dc.DrawLine(pen, new Point(i, r), new Point(i, 0));
}
}
using (var dc = visual2.RenderOpen())
{
for (int i = 0; i < 200; i++)
{
var r = rand.Next(10, 200);
dc.DrawLine(pen, new Point(i, r), new Point(i, 0));
}
visual2.Offset = new Vector(400, 0);
}
}
protected override int VisualChildrenCount
{
get { return 2; }
}
protected override Visual GetVisualChild(int index)
{
return index == 0 ? visual : visual2;
}
protected override Size MeasureOverride(Size availableSize)
{
viewport = availableSize;
owner.InvalidateScrollInfo();
return base.MeasureOverride(availableSize);
}
protected override Size ArrangeOverride(Size finalSize)
{
var value = base.ArrangeOverride(finalSize);
return base.ArrangeOverride(finalSize);
}
Point offset = new Point(0,0);
public void SetHorizontalOffset(double offset)
{
this.offset.X = offset;
this.InvalidateArrange();
}
public void SetVerticalOffset(double offset)
{
this.offset.Y = offset;
}
public Rect MakeVisible(Visual visual, Rect rectangle)
{
throw new NotImplementedException();
}
public bool CanVerticallyScroll { get; set; }
public bool CanHorizontallyScroll { get; set; }
Size extent = new Size(600, 300);
private Size viewport = new Size(0, 0);
public double ExtentWidth
{
get { return extent.Width; }
}
public double ExtentHeight
{
get {return extent.Height; }
}
public double ViewportWidth
{
get { return viewport.Width; }
}
public double ViewportHeight
{
get { return viewport.Height; }
}
public double HorizontalOffset
{
get { return offset.X; }
}
public double VerticalOffset
{
get { return offset.Y; }
}
private ScrollViewer owner;
public ScrollViewer ScrollOwner
{
get { return owner; }
set { owner = value; }
}
}
XAML:
<Window x:Class="TestWpfApp.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:l ="clr-namespace:TestWpfApp"
Title="TestWpfApp" Height="300" Width="300" >
<Grid>
<ScrollViewer CanContentScroll="True" HorizontalScrollBarVisibility="Visible">
<l:TestElement CanHorizontallyScroll="True" />
</ScrollViewer>
</Grid>