创建半透明面板/控制。有没有万无一失的方法？ [英] Creating semi-transparent panels/controls. Is there a foolproof way?
问题描述
我试图创建 System.Windows.Forms.Panel 导出一个半透明的控制。 ：
I am trying to create a semi-transparent control derived from System.Windows.Forms.Panel. :
我已经通过大量的网络文章以及SO问题消失了，都拿出了这一点：
I have gone through numerous web articles as well as SO questions and have come up with this:
class SeeThroughPanel : Panel
{
public SeeThroughPanel()
{
}
protected override CreateParams CreateParams {
get {
var cp = base.CreateParams;
cp.ExStyle |= 0x00000020;
return cp;
}
}
protected override void OnPaint(PaintEventArgs e)
{
//base.OnPaint(e);
e.Graphics.FillRectangle(new SolidBrush(Color.FromArgb(50, 0, 0, 0)), this.ClientRectangle);
}
}
这会导致这样（请注意，这code也不会使它真正半透明的，上面的图像显示在全彩色按钮，不像。）：
Which results this (Note that this code too does not make it really semi-transparent. The button is displayed in full color, unlike in above image):
然而，当我做一些事情，导致的半透明面板的范围内的任何其他控件重画，这是透支了（在这种情况下，我已滚动的底层控制）：
However, as soon as I do something that causes repaint of any other controls within the bounds of the semi-transparent panel, it is overdrawn (In this case, I have scrolled the underlying control):
所以我的问题是，如何才能避免这种情况？这里的的的某种方式。毕竟，Web浏览器处理这种渲染所有的时间。
So my question is, how can I avoid this? There has to be some way. After all, web browsers handle this kind of rendering all the time.
推荐答案
我现在已经做了一些测试。
I have done a few tests now.
正在mixiing几个问题成一体，所以让我们把他们分开：
You are mixiing several problems into one, so let's take them apart:
-
没有web浏览器使用的WinForms C＃编写的。因此，这是没有理由这必须是可能的。
No WebBrowser is written in C# using Winforms. So this is no reason why this must be possible.
您的按钮几乎可以肯定不是在窗体的控件集合。您需要为脚本，它是还是使用一个小窍门UI（*），以将其放置在另一个控制，而不将其添加到它。
Your button almost certainly is not in the Form's Controls collection. You need to either script it to be or use a little UI trick (*) to place it over another Control without adding it to it.
在滚动，你会看到一切滚动控制报告，因为其表面。
When you scroll you will see whatever the scrolling control report as its surface.
下面是两张截图：
这是启动后：
..这是我后滚动有点向右：
..and this is after I scrolled a little to the right:
我用这个code，确保Z顺序是正确的：
I have use this code to make sure the Z-order is right:
button1.Parent = this;
panel1.BringToFront();
button1.BringToFront();
seeThroughPanel1.BringToFront();
请注意如何按钮的空间更是做足了;这显示了旧表面正在被使用。
Note how the the space of the button is spared; this shows how the old surface is being used.
要解决这一点，你就一定得在目前的形式surfacse（也许Control.DrawToBitmap），然后使用的，正确的部分画你的半透明面板。当然，它会隐藏你捕捉窗体的当前表面之前。
To work around this you would have to get at the current Form surfacse (maybe by Control.DrawToBitmap) and then use the right part of that to paint your 'semi-transparent' panel. Of course it would have to hide before you capture the form's current surface.
所有可怕的想法我有过，这似乎是一个最糟糕的。
Of all terrible ideas I have had, this seems to be one of the worst..
*诀窍是将其移动到容器与键盘，不可以鼠标;这一招也只是移动不chnging其父容器。也有用放置控件上的TabControl的标签来...但我太懒了，所以我codeD吧..
* The trick is to move it over the container with the keyboard, not the mouse; with this trick it just moves without chnging its parent container. Also useful for placing a Control on top of the tabs of a TabControl... But I was too lazy for that, so I coded it..
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