如何在C中使用鼠標繪製線條＃

Question

我目前正試圖在Visual Studio WPF窗體中製作一個使用鼠標繪製線條的繪圖。 目前它正在繪製相同的舊線，並繼續繪製它，但我想每次按下鼠標左鍵時畫一條新線。這裏的MainWindows.xaml.cs代碼是什麼樣子：

namespace DrawingLines 
{ 

public partial class MainWindow : Window 
{ 
    public MainWindow() 
    { 
     InitializeComponent(); 
    } 

    private PathFigure _pathFigure = new PathFigure(); 
    PathFigureCollection _pathCollection = new PathFigureCollection(); 
    PathSegmentCollection _segments = new PathSegmentCollection(); 
    private PathGeometry _pathGeometry = new PathGeometry(); 

    private void Window_Loaded(object sender, RoutedEventArgs e) 
    { 
     _pathFigure.Segments = _segments; 
     _pathCollection.Add(_pathFigure); 
     _pathGeometry.Figures = _pathCollection; 
     myPath.Data = _pathGeometry; 
    } 

    private void Window_MouseMove(object sender, MouseEventArgs e) 
    { 
     if (e.LeftButton == MouseButtonState.Pressed) 
     { 
      LineSegment segment = new LineSegment(); 
      segment.Point = e.GetPosition(this); 
      _pathFigure.Segments.Add(segment); 
     } 

    } 

    private void Window_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) 
    { 
     _pathFigure.StartPoint = e.GetPosition(this); 
    } 

    //private void Window_MouseRightButtonDown(object sender, MouseButtonEventArgs e) 
    //{ 

    //} 

    private void button1_Click(object sender, RoutedEventArgs e) 
    { 
     this.Close(); 

    } 
} 

}

而這裏的MainWindow.xmal代碼：

<Window x:Class="DrawingLines.MainWindow" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    Title="Joonistamine" Height="350" Width="525" Loaded="Window_Loaded" MouseMove="Window_MouseMove" MouseLeftButtonDown="Window_MouseLeftButtonDown" MouseRightButtonDown="Window_MouseRightButtonDown"> 
<Grid> 
    <Grid.RowDefinitions> 
     <RowDefinition Height="53*" /> 
     <RowDefinition Height="258*" /> 
    </Grid.RowDefinitions> 
    <Grid.ColumnDefinitions> 
     <ColumnDefinition Width="124*" /> 
     <ColumnDefinition Width="379*" /> 
    </Grid.ColumnDefinitions> 
    <Path Stroke="Black" StrokeThickness="1" Name="myPath" Grid.ColumnSpan="2" Grid.RowSpan="2" /> 
    <Button Content="Exit" Height="25" HorizontalAlignment="Left" Name="button1" VerticalAlignment="Top" Width="46" Click="button1_Click" BorderBrush="Red" Foreground="#FFFF1A1A" /> 
</Grid> 

什麼我做錯了嗎？

Answer 1

在我看來，您正在不斷添加到PathSegment中，而不需要在開始新行時清除它（通過單擊鼠標左鍵）。因此，我想試試這個：

private void Window_MouseLeftButtonDown(object sender, MouseButtonEventArgs e) 
{ 
    _pathFigure.Segments.Clear(); 
    _pathFigure.StartPoint = e.GetPosition(this); 
} 

編輯：...如果你想讓它保留了線，他們不一定連接，你需要爲每行一個單獨的路徑，因爲每個路徑代表一個，連接形狀。

要做到這一點，你就需要修改你的代碼是這樣的：

• 從XAML
• 刪除路徑對於每一個點擊鼠標左鍵，創建一個新的路徑，並將它添加到網格（myGrid.Children.Add（mypath中）
• 從鼠標移動新增點到當前的活動路徑