How to draw an image in TabPage above nested Buttons

问题

How to draw image on tabPage overlapping buttons

Black circles(DrawImage on tabPage8_Paint) should be above the buttons:

http://rghost.ru/6sVBl8mkh/image.png

It must be so: http://rghost.ru/6BgDM77pq/image.png

My code

public SibModem() {

    InitializeComponent();

    tabPage8.Paint += new PaintEventHandler(tabPage8_Paint);
    gettime();

    this.SizeChanged += new EventHandler(this.SibModem_Resize);
}

protected void tabPage8_Paint(object sender, PaintEventArgs e) {

    GraphicsUnit units = GraphicsUnit.Pixel;
    base.OnPaint(e);

    Graphics g = e.Graphics;
    g.DrawImage(bg, 0, 0);

    Rectangle srcRect = new Rectangle(offsetant, 0, w, h);
    g.DrawImage(anten, x, y, srcRect, units);

    Rectangle ussdwaitRect = new Rectangle(offsetussd, 0, 64, 64);
    g.DrawImage(ussdwait, usx, usy, ussdwaitRect, units);
}

回答1:

You can't draw above nested controls, so you need to draw parts of the image onto those Buttons.

So combine drawing onto the tabpage and drawing onto the buttons you need to adorn!

Here is a simple example using only one image:

A few class level variables:

Point iLoc = Point.Empty;
Image img = null;
List<Button> overlaidButtons = new List<Button>();

Prepare the image, its position and a list of possibly overlaid buttons:

public Form1()
{
    InitializeComponent();

    string imgN = @"d:\scrape\gears\gear_12x4hand.png";
    img = Image.FromFile(imgN);
    iLoc = new Point(100, 100);
    overlaidButtons.AddRange(new []{button10,button11,button12,button13 });
    // each button calls the same paint event
    foreach (Button btn in overlaidButtons) btn.Paint += btn_Paint;
}

The common Paint event. We calculate the relative position of the image..

void btn_Paint(object sender, PaintEventArgs e)
{
    Button btn = sender as Button;
    e.Graphics.DrawImage(img, new Point(iLoc.X - btn.Left, iLoc.Y - btn.Top));
}

Note that if the Buttons are nested deeper you need to adapt the calculation to include all levels of nesting!

The TabPage Paint event:

private void tabPage5_Paint(object sender, PaintEventArgs e)
{
    e.Graphics.DrawImage(img, iLoc);
}

回答2:

Try BringToFront method, it brings the control to the front of the z-order.

See this reference on MSDN: https://msdn.microsoft.com/en-us/library/system.windows.forms.control.bringtofront(v=vs.110).aspx

来源：https://stackoverflow.com/questions/34195719/how-to-draw-an-image-in-tabpage-above-nested-buttons

标签

forms

draw