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调用EnableScrollBar时滚动条闪烁

pinvoke scroll winforms .net c#

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TheCloudlessSky · 技术社区 · 16 年前

我用p/invoke来调用 EnableScrollBar 从 user32.dll ( MSDN reference ). 我注意到,当滚动条被启用时,它看起来就像没有应用主题一样绘制,然后用应用的主题重新绘制。到目前为止,我只测试过Windows7。有

编辑: 下面是一些代码来显示发生了什么(转储到带有滚动条的窗体中):

private class Native
{
    [DllImport("user32.dll")]
    public static extern bool EnableScrollBar(IntPtr hWnd, uint wSBflags, uint wArrows);

    public static class SBArrows
    {
        public const uint ESB_ENABLE_BOTH = 0;
        public const uint ESB_DISABLE_BOTH = 3;
        public const uint ESB_DISABLE_LEFT = 1;
        public const uint ESB_DISABLE_RIGHT = 2;
        public const uint ESB_DISABLE_UP = 1;
        public const uint ESB_DISABLE_DOWN = 2;
        public const uint ESB_DISABLE_LTUP = 1;
        public const uint ESB_DISABLE_RTDN = 2;
    }

    public static class SBFlags
    {
        public const uint SB_HORZ = 0;
        public const uint SB_VERT = 1;
        public const uint SB_CTL = 2;
        public const uint SB_BOTH = 3;
    }
}


private bool Switch = false;

protected override void OnMouseDown(MouseEventArgs e)
{
    Native.EnableScrollBar(this.Handle, Native.SBFlags.SB_HORZ, this.Switch ? Native.SBArrows.ESB_DISABLE_BOTH : Native.SBArrows.ESB_ENABLE_BOTH);
    this.Switch = !this.Switch;
}

Native.SendMessage(this.Handle, Native.WindowMessages.WM_SETREDRAW, new IntPtr(0), IntPtr.Zero);
Native.EnableScrollBar(this.Handle, Native.SBFlags.SB_HORZ, Native.SBArrows.ESB_ENABLE_BOTH);
Native.SendMessage(this.Handle, Native.WindowMessages.WM_SETREDRAW, new IntPtr(1), IntPtr.Zero);

1 回复 | 直到 16 年前

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Hans Passant 16 年前

    protected override void OnMouseDown(MouseEventArgs e) {
        Native.LockWindowUpdate(this.Handle);
        Native.EnableScrollBar(this.Handle, Native.SBFlags.SB_HORZ, this.Switch ? Native.SBArrows.ESB_DISABLE_BOTH : Native.SBArrows.ESB_ENABLE_BOTH);
        //this.Invalidate();
        Native.LockWindowUpdate(IntPtr.Zero);
        this.Switch = !this.Switch;
    }