C# 控制 WndProc()接收处理消息的频率

Question

 DateTime nextScanTime = DateTime.MinValue;        protected override void WndProc(ref Message msg)
        {
            try
            {                if (msg.Msg == WM_SCANCODE_ENGINE_NOTIFY && DateTime.Now>nextScanTime)   // BarCode的自定义消息通知
                {
                    nextScanTime = DateTime.Now.AddSeconds(10); //<===这增加10秒
                    uint nDataLen = 0; //= (int)msg.WParam;
                    uint nBarCodeType = 0;// = (uint)msg.LParam;
                    byte[] BarCodeData;
                    barcode.GetBarCodeReaderRes(ref nBarCodeType, ref  nDataLen, null);
                    if (nDataLen > 0)
                    {                        string mess = "正在处理";
                        BarCodeData = new byte[nDataLen];
                        barcode.GetBarCodeReaderRes(ref nBarCodeType, ref  nDataLen, BarCodeData);
                        string str1 = Encoding.Default.GetString(BarCodeData, 0, (int)nDataLen);
                        this._BaseForm.DecodeText(ref mess);
                        this._BaseForm.GetTick(str1, 1);
                        barcode.DoBeep(1, 50, 80);                    }
                    if (_BaseForm.PrintMessage != "" && _BaseForm.isScan)
                    {
                        int ct = barcode.DoPrint(_BaseForm.PrintMessage, "宋体", 30, 100);                    }
                }
                else
                {
                    base.WndProc(ref msg);                }
            }
            catch (Exception ex)
            {            }        }

Answer 1

if (!lastScanTime.HasValue || DateTime.Now.Subtract(lastScanTime.Value) > TimeSpan.FromSeconds(10))
{}