如果在启动窗口画直线随着鼠标移动

1914780299 · 发表于 2023-10-18 16:29:24

按住就是画直线的起始位置
松开就是结束位置
如果鼠标没松开画直线随着鼠标移动

星星之夜 · 发表于 2023-10-18 16:29:25

public partial class MainForm : Form
{
private bool isDrawing;
private Point startPoint;
private Point endPoint;

public MainForm()
{
      InitializeComponent();

      // 添加鼠标按下和松开事件处理程序
      this.MouseDown += MainForm_MouseDown;
      this.MouseUp += MainForm_MouseUp;

      // 添加鼠标移动事件处理程序
      this.MouseMove += MainForm_MouseMove;

      // 设置双缓冲，以减少绘制的闪烁
      this.DoubleBuffered = true;
}

private void MainForm_MouseDown(object sender, MouseEventArgs e)
{
      if (e.Button == MouseButtons.Left)
      {
         isDrawing = true;
         startPoint = e.Location;
         endPoint = e.Location;
         this.Invalidate(); // 强制绘制
      }
}

private void MainForm_MouseUp(object sender, MouseEventArgs e)
{
      if (e.Button == MouseButtons.Left)
      {
         isDrawing = false;
         endPoint = e.Location;
         this.Invalidate(); // 强制绘制
      }
}

private void MainForm_MouseMove(object sender, MouseEventArgs e)
{
      if (isDrawing)
      {
         endPoint = e.Location;
         this.Invalidate(); // 强制绘制
      }
}

protected override void OnPaint(PaintEventArgs e)
{
      base.OnPaint(e);

      // 在启动窗口上绘制直线
      if (isDrawing)
      {
         using (Pen pen = new Pen(Color.Black, 2))
         {
            e.Graphics.DrawLine(pen, startPoint, endPoint);
         }
      }
}
}