滚动时在面板中平滑绘制或绘画子控件 [英] Smooth drawing or painting of child controls in Panel while scrolling

问题描述

在Tab控件的TabPage中使用Panel控件时，我有很多子控件，例如RichTextBox，Button，Label等.

While using Panel control in TabPage of Tab control, I have quite a few child controls like RichTextBox, Buttons, Labels etc.

问题是当我在面板中滚动时，内部出现了闪烁.子控件不会像已经存在那样被顺畅地显示/淹没/绘制.

Problem is when I scroll in the Panel, there is a flickering inside. The child controls are not being shown/drown/painted smoothly like they are already there.

寻找可以使滚动平滑并消除闪烁效果的东西. 任何建议都会有很大帮助.我尝试了其他几种方法，例如DoubleBuffered，但并没有真正起作用.

Looking for something that could make this scrolling smooth and remove the flickering effect. Any suggestions would help a lot. I tried a several other methods like DoubleBuffered, but didn't really work.

推荐答案

好吧，我通过结合其他不同的建议解决了这个问题，以下是为我消除了闪烁的代码，实际上是使用Win API将其变为DoubleBuffered.

Well I solved the problem with combination of different other suggestions, below is the code that removed flickering for me, essentially making it DoubleBuffered using Win API.

参考文献此处和这里.

public partial class SmoothScrollPanel : UserControl
{
    public SmoothScrollPanel()
    {
        InitializeComponent();
        // this.DoubleBuffered = true;
    }

    private const int WM_HSCROLL = 0x114;
    private const int WM_VSCROLL = 0x115;

    protected override void WndProc(ref Message m)
    {
        if ((m.Msg == WM_HSCROLL || m.Msg == WM_VSCROLL)
        && (((int)m.WParam & 0xFFFF) == 5))
        {
            // Change SB_THUMBTRACK to SB_THUMBPOSITION
            m.WParam = (IntPtr)(((int)m.WParam & ~0xFFFF) | 4);
        }
        base.WndProc(ref m);
    }

    protected override CreateParams CreateParams
    {
        get
        {
            var cp = base.CreateParams;
            cp.ExStyle |= 0x02000000;    // Turn on WS_EX_COMPOSITED
            return cp;
        }
    }
}

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