如何在C#中使用鼠标绘制和移动形状

Question

我是C#编程的新手,想要求一些帮助.我正在尝试使用鼠标左键移动我在Windows应用程序表单上绘制的颜色填充矩形,我正在尝试使用鼠标右键将其拖放到另一个位置.目前我已设法绘制矩形,但右键单击是拖动整个表单.

这是我的代码:

public partial class Form1 : Form
{
    private Point MouseDownLocation;

    public Form1()
    {
        InitializeComponent();
        this.DoubleBuffered = true;
    }
    Rectangle rec = new Rectangle(0, 0, 0, 0);

    protected override void OnPaint(PaintEventArgs e)
    {   
        e.Graphics.FillRectangle(Brushes.DeepSkyBlue, rec);
    }


    protected override void OnMouseDown(MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left) 
        {
            rec = new Rectangle(e.X, e.Y, 0, 0);
            Invalidate();

        }
        if (e.Button == MouseButtons.Right)
        {
            MouseDownLocation = e.Location;
        }
    }
    protected override void OnMouseMove(MouseEventArgs e)
    {             

        if (e.Button == MouseButtons.Left)
        {
            rec.Width = e.X - rec.X;
            rec.Height = e.Y - rec.Y;
            Invalidate();
        }

        if (e.Button == MouseButtons.Right)
        {
            this.Left = e.X + this.Left - MouseDownLocation.X;
            this.Top = e.Y + this.Top - MouseDownLocation.Y;

        }
    }

}

我只需要用鼠标右键拖放矩形.

编辑:谢谢你,我得到了我的答案非常快,这里的代码是有效的:

public partial class Form1 : Form
{
    private Point MouseDownLocation;

    public Form1()
    {
        InitializeComponent();
        this.DoubleBuffered = true;            
    }

    Rectangle rec = new Rectangle(0, 0, 0, 0);

    protected override void OnPaint(PaintEventArgs e)
    {
        e.Graphics.FillRectangle(Brushes.DeepSkyBlue, rec);
        //Generates the shape            
    }

    protected override void OnMouseDown(MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        //can also use this one:
        //if (e.Button == System.Windows.Forms.MouseButtons.Left)
        {
            rec = new Rectangle(e.X, e.Y, 0, 0);
            Invalidate();

        }
        if (e.Button == MouseButtons.Right)
        {
            MouseDownLocation = e.Location;
        }
    }
    protected override void OnMouseMove(MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            rec.Width = e.X - rec.X;
            rec.Height = e.Y - rec.Y;
            this.Invalidate();
        }

        if (e.Button == MouseButtons.Right)
        {
            rec.Location = new Point((e.X - MouseDownLocation.X) + rec.Left, (e.Y - MouseDownLocation.Y) + rec.Top);
            MouseDownLocation = e.Location;
            this.Invalidate();
        }
    }

}

Answer 1

这似乎有效

    protected override void OnMouseMove(MouseEventArgs e)
    {


        if (e.Button == MouseButtons.Left)
        {
            rec.Width = e.X - rec.X;
            rec.Height = e.Y - rec.Y;
            this.Invalidate();
        }

        if (e.Button == MouseButtons.Right)
        {
            rec.Location = new Point((e.X-MouseDownLocation.X) + rec.Left, (e.Y-MouseDownLocation.Y) + rec.Top);
            MouseDownLocation = e.Location;
            this.Invalidate();
        }
    }