我正在尝试使用绘图板制作应用程序。我WriteableBitmapEx根据自己的目的选择并开始开发。我遵循了这个库官方网站上的简短教程，但不幸的是我无法SetPixel(...)在我的位图上绘图。谁能帮我解决它？
XAML 代码：
<Page
x:Class="WritableBitmapApp.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:WritableBitmapApp"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d"
Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
<Grid>
<Image x:Name="ImageControl"
Source="Hobbit.png"
Tapped="ImageControl_Tapped"
Height="512"
Width="350"/>
</Grid>
和 C# 代码：
public sealed partial class MainPage : Page
{
public WriteableBitmap writeableBmp;
public MainPage()
{
this.InitializeComponent();
this.NavigationCacheMode = NavigationCacheMode.Required;
writeableBmp = BitmapFactory.New(512, 350);
writeableBmp.Clear(Colors.Black);
ImageControl.Source = writeableBmp;
writeableBmp.GetBitmapContext();
}
/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached.
/// This parameter is typically used to configure the page.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
// TODO: Prepare page for display here.
// TODO: If your application contains multiple pages, ensure that you are
// handling the hardware Back button by registering for the
// Windows.Phone.UI.Input.HardwareButtons.BackPressed event.
// If you are using the NavigationHelper provided by some templates,
// this event is handled for you.
}
private void ImageControl_Tapped(object sender, TappedRoutedEventArgs e)
{
var pnt = e.GetPosition(ImageControl);
try
{
writeableBmp.DrawLine(0, 0, (int)pnt.X, (int)pnt.Y, Colors.White);
ImageControl.Source = writeableBmp;
writeableBmp.GetBitmapContext();
writeableBmp.Invalidate();
ImageControl.Source = writeableBmp;
}
catch(Exception ex)
{
}
}
}