在C中使用鼠標點繪製多邊形＃

Question

我需要能夠使用鼠標點擊位置繪製多邊形。 這裏是我當前的代碼：

//the drawshape varible is called when a button is pressed to select use of this tool 
      if (DrawShape == 4) 
       { 
        Point[] pp = new Point[3]; 
        pp[0] = new Point(e.Location.X, e.Location.Y); 
        pp[1] = new Point(e.Location.X, e.Location.Y); 
        pp[2] = new Point(e.Location.X, e.Location.Y); 
        Graphics G = this.CreateGraphics(); 
        G.DrawPolygon(Pens.Black, pp); 
       } 

感謝

Answer 1

確定這裏是一些示例代碼：

private List<Point> polygonPoints = new List<Point>(); 

private void TestForm_MouseClick(object sender, MouseEventArgs e) 
{ 
    switch(e.Button) 
    { 
     case MouseButtons.Left: 
      //draw line 
      polygonPoints.Add(new Point(e.X, e.Y)); 
      if (polygonPoints.Count > 1) 
      { 
       //draw line 
       this.DrawLine(polygonPoints[polygonPoints.Count - 2], polygonPoints[polygonPoints.Count - 1]); 
      } 
      break; 

     case MouseButtons.Right: 
      //finish polygon 
      if (polygonPoints.Count > 2) 
      { 
       //draw last line 
       this.DrawLine(polygonPoints[polygonPoints.Count - 1], polygonPoints[0]); 
       polygonPoints.Clear(); 
      } 
      break; 
    } 
} 

private void DrawLine(Point p1, Point p2) 
{ 
    Graphics G = this.CreateGraphics(); 
    G.DrawLine(Pens.Black, p1, p2); 
} 

Answer 2

首先，添加以下代碼：

List<Point> points = new List<Point>(); 

在您繪製的對象，捕捉onclick事件。其中一個參數應具有點擊的X和Y座標。將它們添加到點數組：

points.Add(new Point(xPos, yPos)); 

然後終於，你在哪裏畫線，使用此代碼：

if (DrawShape == 4) 
{ 
    Graphics G = this.CreateGraphics(); 
    G.DrawPolygon(Pens.Black, points.ToArray()); 
} 

編輯：

好了，以上代碼不完全正確。首先，它最有可能是Click事件而不是OnClick事件。其次，爲了讓鼠標的位置，你需要申報了點陣列的兩個變量，

int x = 0, y = 0; 

然後讓鼠標移動事件：

private void MouseMove(object sender, MouseEventArgs e) 
    { 
     x = e.X; 
     y = e.Y; 
    } 

然後，在你的Click事件：

private void Click(object sender, EventArgs e) 
    { 
     points.Add(new Point(x, y)); 
    }