這是給你的demo，希望對你有幫助。
XAML 頁面：
<Grid x:Name="rootGrid" Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
</Grid>
后面的代碼：
public sealed partial class MainPage : Page
{
public MainPage()
{
this.InitializeComponent();
rootGrid.PointerPressed += RootGrid_PointerPressed;
rootGrid.PointerMoved += RootGrid_PointerMoved;
rootGrid.PointerReleased += RootGrid_PointerReleased;
rootGrid.PointerExited += RootGrid_PointerExited;
}
int pointerId = -1;
Line curLine = null;
private void RootGrid_PointerExited(object sender, PointerRoutedEventArgs e)
{
OnComplete();
}
private void RootGrid_PointerReleased(object sender, PointerRoutedEventArgs e)
{
OnComplete();
}
private void OnComplete()
{
// reset pointerId so that other pointers may enter live rendering mode
pointerId = -1;
curLine = null;
}
private void RootGrid_PointerMoved(object sender, PointerRoutedEventArgs e)
{
var pointerPoint = e.GetCurrentPoint(rootGrid);
if (pointerId == (int)pointerPoint.PointerId)
{
curLine.X2 = pointerPoint.Position.X;
curLine.Y2 = pointerPoint.Position.Y;
curLine.Stroke = new SolidColorBrush(Colors.Red);
}
}
private void RootGrid_PointerPressed(object sender, PointerRoutedEventArgs e)
{
// Make sure no pointer is already drawing (we allow only one 'active' pointer at a time)
if (pointerId == -1)
{
var pointerPoint = e.GetCurrentPoint(rootGrid);
if (!pointerPoint.Properties.IsLeftButtonPressed)
return;
curLine = new Line();
var position = pointerPoint.Position;
curLine.X1 = pointerPoint.Position.X;
curLine.Y1 = pointerPoint.Position.Y;
curLine.StrokeThickness = 1;
rootGrid.Children.Add(curLine);
//save pointer id so that no other pointer can ink until this one is released
pointerId = (int)pointerPoint.PointerId;
}
}
}
