C#Panel.Refresh()不调用paint方法

Question

我试图调用panel1 paint方法用橙色线重新绘制面板(它用蓝线启动).

我已经尝试过invalidate(),update()和refresh(),但似乎没有任何东西可以调用panel1的paint事件......

paint事件处理程序已添加到panel1:

this.panel1.Paint += new System.Windows.Forms.PaintEventHandler(this.panel1_Paint);

有人可以帮忙吗？

static class Program
{
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);

        Form1 testForm = new Form1();
        Application.Run(testForm);

        testForm.drawNewLine();
    }
}

---

public partial class Form1 : Form
{
    bool blueLine = true;
    bool orangeLine = false;

    public Form1()
    {
        InitializeComponent();
    }

    private void panel1_Paint(object sender, PaintEventArgs e)
    {
        Graphics g = e.Graphics;

        if (blueLine == true)
        {
            Pen bluePen = new Pen(Color.Blue, 3);
            g.DrawLine(bluePen, 30, 50, 30, 250);
        }
        else if (orangeLine == true)
        {
            Pen orangePen = new Pen(Color.Orange, 3);
            g.DrawLine(orangePen, 30, 50, 30, 250);
        }

        g.Dispose();
    }

    public void drawNewLine()
    {
        blueLine = false;
        orangeLine = true;
        //panel1.Invalidate();
        //panel1.Update();
        panel1.Refresh();
    }
}

Answer 1

Application.Run(testForm);阻止窗体关闭,所以当drawNewLine()调用时 - 窗体不再存在(创建一个按钮,在点击时调用它并检查自己,代码正常工作).Invalidate()应该工作得很好.

此外,您不应该处理Graphics在paint事件中传递给您的代码的对象.你不负责创建它,所以让创建它的代码销毁它.

此外,处理Pen对象,因为您正在创建它们.