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  • usb 视频设备 按钮消息处理 和普通usb连接的事件处理

    usb 视频设备 按钮消息处理 和普通usb连接的事件处理 

    (c#版,c++/c可仿照修改)

    最近要做个usb camera的例子,试过了很多方法,一般的usb连接的处理方法:

    (1) define message variables in form class:

            public const int WM_DEVICECHANGE = 0x219;
            public const int DBT_DEVICEARRIVAL = 0x8000;
            public const int DBT_CONFIGCHANGECANCELED = 0x0019;
            public const int DBT_CONFIGCHANGED = 0x0018;
            public const int DBT_CUSTOMEVENT = 0x8006;
            public const int DBT_DEVICEQUERYREMOVE = 0x8001;
            public const int DBT_DEVICEQUERYREMOVEFAILED = 0x8002;
            public const int DBT_DEVICEREMOVECOMPLETE = 0x8004;
            public const int DBT_DEVICEREMOVEPENDING = 0x8003;
            public const int DBT_DEVICETYPESPECIFIC = 0x8005;
            public const int DBT_DEVNODES_CHANGED = 0x0007;
            public const int DBT_QUERYCHANGECONFIG = 0x0017;
            public const int DBT_USERDEFINED = 0xFFFF;

    (2)  override form class WndProc method:

        protected override void WndProc(ref Message m)
            {
                try
                {
                    if (m.Msg == WM_DEVICECHANGE)
                    {
                        switch (m.WParam.ToInt32())
                        {
                            case WM_DEVICECHANGE:
                                break;
                            case DBT_DEVICEARRIVAL://U盘插入
                                DriveInfo[] s = DriveInfo.GetDrives();
                                foreach (DriveInfo drive in s)
                                {
                                    if (drive.DriveType == DriveType.Removable)
                                    {
                                        listBox1.Items.Add("U盘已插入,盘符为:" + drive.Name.ToString());
                                        break;
                                    }
                                }
                                break;
                            case DBT_CONFIGCHANGECANCELED:
                                break;
                            case DBT_CONFIGCHANGED:
                                break;
                            case DBT_CUSTOMEVENT:
                                break;
                            case DBT_DEVICEQUERYREMOVE:
                                break;
                            case DBT_DEVICEQUERYREMOVEFAILED:
                                break;
                            case DBT_DEVICEREMOVECOMPLETE: //U盘卸载
                                break;
                            case DBT_DEVICEREMOVEPENDING:
                                break;
                            case DBT_DEVICETYPESPECIFIC:
                                break;
                            case DBT_DEVNODES_CHANGED:
                                break;
                            case DBT_QUERYCHANGECONFIG:
                                break;
                            case DBT_USERDEFINED:
                                break;
                            default:
                                break;
                        }
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
                base.WndProc(ref m);
            }
        }

    此法的局限性:

    对于一般的u盘(u disk/storage),可以处理u盘的insert/remove事件,但是不能处理如camera之类非存储的usb device.

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  • 原文地址:https://www.cnblogs.com/SunWentao/p/2202294.html
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