关于画图的2个问题

[bao0614]

1，当选择form1的按钮时怎样可以在form2的picturebox中画图？应该怎样创建picturebox的grahics对象？

2，怎样实现图像的整体、部分选取，复制？并且在选取时被选中的区域有个虚线框，在复制完后虚线框消失？

请高手们不吝赐教 最好有代码 谢谢！

[真相重于对错]

使用消息，或者事件

[jason909]

要实现功能很多不是技术问题，而是设计的问题，要先做好设计

[北京的雾霾天]

继承PictureBox控件，然后添加类似如下的代码：

//鼠标拖动的虚框实现
private Point m_StartPoint;
private Point m_LastPoint;

protected override void OnMouseDown(MouseEventArgs e)
{
	base.OnMouseDown(e);
	this.m_StartPoint = e.Location;
	m_LastPoint = this.m_StartPoint;
}
protected override void OnMouseUp(MouseEventArgs e)
{
	base.OnMouseUp(e);
	Point endPoint = e.Location;
	int l = m_LastPoint.X > this.m_StartPoint.X ? this.m_StartPoint.X : m_LastPoint.X;
	int t = m_LastPoint.Y > this.m_StartPoint.Y ? this.m_StartPoint.Y : m_LastPoint.Y;
	int r = m_LastPoint.X > this.m_StartPoint.X ? m_LastPoint.X : this.m_StartPoint.X;
	int b = m_LastPoint.Y > this.m_StartPoint.Y ? m_LastPoint.Y : this.m_StartPoint.Y;

	Rectangle rect = Rectangle.FromLTRB(l, t, r, b);
	ControlPaint.DrawReversibleFrame(this.RectangleToScreen(rect), SystemColors.Highlight, FrameStyle.Dashed);
}
protected override void OnMouseMove(MouseEventArgs e)
{
	base.OnMouseMove(e);
	if (e.Button == MouseButtons.Left)
	{
		Point endPoint = e.Location;
		int l = m_LastPoint.X > this.m_StartPoint.X ? this.m_StartPoint.X : m_LastPoint.X;
		int t = m_LastPoint.Y > this.m_StartPoint.Y ? this.m_StartPoint.Y : m_LastPoint.Y;
		int r = m_LastPoint.X > this.m_StartPoint.X ? m_LastPoint.X : this.m_StartPoint.X;
		int b = m_LastPoint.Y > this.m_StartPoint.Y ? m_LastPoint.Y : this.m_StartPoint.Y;

		Rectangle rect = Rectangle.FromLTRB(l, t, r, b);
		ControlPaint.DrawReversibleFrame(this.RectangleToScreen(rect), SystemColors.Highlight, FrameStyle.Dashed);

		int _l = endPoint.X > this.m_StartPoint.X ? this.m_StartPoint.X : endPoint.X;
		int _t = endPoint.Y > this.m_StartPoint.Y ? this.m_StartPoint.Y : endPoint.Y;
		int _r = endPoint.X > this.m_StartPoint.X ? endPoint.X : this.m_StartPoint.X;
		int _b = endPoint.Y > this.m_StartPoint.Y ? endPoint.Y : this.m_StartPoint.Y;

		Rectangle _rect = Rectangle.FromLTRB(_l, _t, _r, _b);
		ControlPaint.DrawReversibleFrame(this.RectangleToScreen(_rect), SystemColors.Highlight, FrameStyle.Dashed);
		m_LastPoint = endPoint;
	}
}

在Form1中生成Form2的PictureBox的Graphics，可以在Form2中编写一个方法：
public Graphics GetGraphics()
{
return this.PictureBox1.CreateGraphics();
}

在Form1中添加Form2的实例的引用，通过实例引用调用方法：

Graphics g = this.form2.GetGraphics();
...
g.Dispose();

[banping]

上面 说得很详细了，虚线筐就是用鼠标事件，draw一个矩形出来。然后不用的时候再重新画这个图片。