我正在尝试在一个图片框中绘制一些椭圆,该图片框在 C# 中的表单加载上包含一个 PNG。当我执行下面的代码时,我看到我的省略号半秒钟,然后我就再也看不到它们了。
当我点击我的图片框时,我可以画一个椭圆,但是当我最小化表格时,它们就不再出现了。
我读到过您不应该将绘图代码放在 formload 中,而应该放在 OnPaint 方法中,我就是这样做的。我不知道该尝试什么了。谢谢。 (请注意,我已经对一些代码进行了注释以显示我的尝试)。
public partial class FormParterre : Form
{
Graphics g;
float circleSize = 15;
//Brushes rouge = new Brushes (Brushes.Red);
ReservationBilletSiegeDAO reservationBilletSiegeDAO = new ReservationBilletSiegeDAO();
SiegeDAO siegeDAO = new SiegeDAO();
List <Siege> sieges;
List<ReservationBilletSiege> rbs;
ReservationBillet reservationBillet = new ReservationBillet();
ReservationBilletSiege reservationBilletSiege;
SolidBrush semiTransBrush;
public FormParterre()
{
InitializeComponent();
pictureBox1.Image = new Bitmap("./parterre.png");
g = pictureBox1.CreateGraphics();
}
public FormParterre(ReservationBillet rb)
{
reservationBillet = rb;
pictureBox1.Image = new Bitmap("./parterre.png");
g = pictureBox1.CreateGraphics();
InitializeComponent();
}
protected override void OnPaintBackground(PaintEventArgs e)
{
// do nothing! prevents flicker
}
protected override void OnPaint(PaintEventArgs e)
{
sieges = siegeDAO.readAll();
rbs = reservationBilletSiegeDAO.readAll();
foreach (ReservationBilletSiege reservationBilletSiegeTMP in rbs)
{
Console.WriteLine(reservationBilletSiegeTMP.toString());
int x = siegeDAO.read(reservationBilletSiegeTMP.idSiege).xValeur;
int y = siegeDAO.read(reservationBilletSiegeTMP.idSiege).yValeur;
float xx = (float)x;
float yy = (float)y;
Console.WriteLine("le x: " + xx);
Console.WriteLine("le y: " + yy);
/*e.Graphics.FillRectangle(new SolidBrush(BackColor), e.ClipRectangle);*/
g.FillEllipse(new SolidBrush(Color.FromArgb(128, 0, 0, 255)), xx - circleSize / 2, yy - circleSize / 2, circleSize, circleSize);
}
}
private void pictureBox1_Click(object sender, EventArgs e)
{
MouseEventArgs me = (MouseEventArgs)e;
txtX.Text = me.X.ToString();
txtY.Text = me.Y.ToString();
Console.WriteLine("click");
g.FillEllipse(new SolidBrush(Color.FromArgb(128, 0, 0, 255)), float.Parse(txtX.Text) - circleSize / 2, float.Parse(txtY.Text) - circleSize / 2, circleSize, circleSize);
}
private void FormParterre_Shown(object sender, EventArgs e)
{
}
private void FormParterre_Load(object sender, EventArgs e)
{
/*sieges = siegeDAO.readAll();
//semiTransBrush = new SolidBrush(Color.FromArgb(128, 0, 0, 255));
rbs = reservationBilletSiegeDAO.readAll();
foreach (ReservationBilletSiege reservationBilletSiegeTMP in rbs)
{
Console.WriteLine(reservationBilletSiegeTMP.toString());
int x = siegeDAO.read(reservationBilletSiegeTMP.idSiege).xValeur;
int y = siegeDAO.read(reservationBilletSiegeTMP.idSiege).yValeur;
float xx = (float)x;
float yy = (float)y;
Console.WriteLine("le x: " + xx);
Console.WriteLine("le y: " + yy);
g.FillEllipse(new SolidBrush(Color.FromArgb(128, 0, 0, 255)), xx - circleSize / 2, yy - circleSize / 2, circleSize, circleSize);
}*/
}
}
最佳答案
您需要使用传递给您的 PaintEventArgs.Graphics
属性在 OnPaint
方法中进行绘制。如果您想在 PictureBox
上绘画,您可以尝试订阅它的 Paint
事件并在那里绘画。
这对我有用:
public void Form1()
{
InitializeComponent();
pictureBox1.Paint += pictureBox1_Paint;
}
private void pictureBox1_Paint(object sender, PaintEventArgs e)
{
e.Graphics.FillEllipse(Brushes.Red, pictureBox1.ClientRectangle);
}
关于c# - 无法在 C# 中的表单加载上绘制椭圆,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/20011079/