在C中的一个Picturebox上绘制一个箭头＃

Question

我希望能够从一个鼠标点击位置绘制一个直线箭头到另一个鼠标，就像在PowerPoint中一样。它需要能够在一个PictureBox画为好，请大家帮忙，

感谢

Answer 1

下面是一些基本的代码绘制从鼠标按下在PictureBox线的当前位置。
您只需要为箭头绘制更多线条或三角形。

public partial class Form1 : Form 
{ 
    private bool isMoving = false; 
    private Point mouseDownPosition = Point.Empty; 
    private Point mouseMovePosition = Point.Empty; 
    private List<Tuple<Point, Point>> lines = new List<Tuple<Point, Point>>(); 
    public Form1() 
    { 
     InitializeComponent(); 

     // 
     // pictureBox1 
     // 
     this.pictureBox1.Location = new System.Drawing.Point(0, 0); 
     this.pictureBox1.Name = "pictureBox1"; 
     this.pictureBox1.Size = new System.Drawing.Size(231, 235); 
     this.pictureBox1.TabIndex = 0; 
     this.pictureBox1.TabStop = false; 
     this.pictureBox1.Paint += new System.Windows.Forms.PaintEventHandler(this.pictureBox1_Paint); 
     this.pictureBox1.MouseDown += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseDown); 
     this.pictureBox1.MouseMove += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseMove); 
     this.pictureBox1.MouseUp += new System.Windows.Forms.MouseEventHandler(this.pictureBox1_MouseUp); 
     this.Controls.Add(this.pictureBox1); 
    } 

    private void pictureBox1_Paint(object sender, PaintEventArgs e) 
    { 
     var g = e.Graphics; 
     if (isMoving) 
     { 
      g.Clear(pictureBox1.BackColor); 
      g.DrawLine(Pens.Black, mouseDownPosition, mouseMovePosition); 
      foreach (var line in lines) 
      { 
       g.DrawLine(Pens.Black, line.Item1, line.Item2); 
      } 
     } 
    } 

    private void pictureBox1_MouseDown(object sender, MouseEventArgs e) 
    { 
     isMoving = true; 
     mouseDownPosition = e.Location; 
    } 

    private void pictureBox1_MouseMove(object sender, MouseEventArgs e) 
    { 
     if (isMoving) 
     { 
      mouseMovePosition = e.Location; 
      pictureBox1.Invalidate(); 
     } 
    } 

    private void pictureBox1_MouseUp(object sender, MouseEventArgs e) 
    { 
     if (isMoving) 
     { 
      lines.Add(Tuple.Create(mouseDownPosition, mouseMovePosition)); 
     } 
     isMoving = false; 
    } 
} 

Answer 2

人们很容易得出在你制定了如何画一个PictureBox线a previous question以同样的方式箭头。

所有你需要做的是你已经使用了画线的Pen对象指定一个StartCap或EndCap。直观上，StartCap属性允许您指定在使用Pen对象绘制的任何线条的开头处使用的封面样式，而EndCap属性允许您为线条末尾指定封面样式。

几种不同LineCap款式可供选择，包括：

Flat   Specifies a flat line cap. 
Square  Specifies a square line cap. 
Round   Specifies a round line cap. 
Triangle  Specifies a triangular line cap. 
NoAnchor  Specifies no anchor. 
SquareAnchor Specifies a square anchor line cap. 
RoundAnchor Specifies a round anchor cap. 
DiamondAnchor Specifies a diamond anchor cap. 
ArrowAnchor Specifies an arrow-shaped anchor cap. 
Custom  Specifies a custom line cap. 
AnchorMask Specifies a mask used to check whether a line cap is an anchor cap. 

你也许会发现在ArrowAnchor风格在这种情况下最有用：只需指定一个ArrowAnchor作为LineCap风格为线的起点或终点（取决于你希望箭头指向的方向）。

下面的代码将以此为绿色，右向箭头与4线厚度：

private void pictureBox1_Paint(object sender, PaintEventArgs e) 
{ 
//Create a new pen to draw the arrow with 
using (Pen p = new Pen(Brushes.Green, 4f)) 
{ 
    //Specify the EndCap, because we're drawing a right-facing arrow 
    p.EndCap = System.Drawing.Drawing2D.LineCap.ArrowAnchor; 

    //Draw the arrow 
    e.Graphics.DrawLine(p, 0, 0, 30, 45); 
} 
} 

Answer 3

参考阿尔宾Sunnanbo的答案，这是伟大的东西

如果你想到平局箭头只需更换

g.DrawLine(Pens.Black, mouseDownPosition, mouseMovePosition); 

到

Pen p = new Pen(Color.Black,3); 
p.StartCap = System.Drawing.Drawing2D.LineCap.ArrowAnchor; 
g.DrawLine(p, mouseDownPosition, mouseMovePosition); 
p.Dispose();