如何：WCF服务检查Windows窗体用户是否仍然活动？

Question

我有以下情形：Windows Mobile 6.1（.NET Compact Framwork 2.0）从服务器中消耗多个WCF服务的应用程序（同时运行于多个设备中）。要使用Windows Form应用程序，用户必须登录。

服务器消耗SAP系统中的数据。 WCF服务器必须根据记录的用户检索来自SAP的一些信息。所以，我的Windows窗体应用程序必须（不时）显示它们仍然运行到我的WCF服务器。

我该怎么做才能完成这项任务？我在想创建一个后台任务来更新WCF服务器的SQL服务器。 （如会话控制）。

Answer 1

您可以在应用程序中侦听Power State更改。该文档显示它仅适用于Windows Mobile 6.5，但我在运行.NET CF 3.5的Windows Mobile 5.0应用程序中使用它。

就像手机一样，如果移动设备长时间不使用，操作系统会显示电池在实际使用之前处于相同的电平。所以，这不是很可靠。

但是，您可以侦听事件（like POWER_STATE_CRITICAL等），并让您的软件进行相应地与您的WCF服务器交互的更改。

下面是我使用的东西的编辑版本。

这不会解决你的问题100％，但它应该让你知道如何去做你需要的东西。

using Microsoft.WindowsMobile.Status; 

BatteryLevel _batteryLevel; 
BatteryState _batteryState; 

void Mobile5_Load(object sender, EventArgs e) { 
    _batteryLevel = (BatteryLevel)SystemState.GetValue(SystemProperty.PowerBatteryStrength); 
    _batteryState = (BatteryState)SystemState.GetValue(SystemProperty.PowerBatteryState); 
    if (!BatteryCritical(false)) { 
    // Continue 
    } 
} 
/// <summary> 
/// Sets the Battery Level and Battery State for the Mobile Device 
/// <para><value>showDialog=True show the dialog box</value></para> 
/// <para><value>Returns True <b>if</b> the battery is in a critical state</value></para> 
/// </summary> 
/// <param name="showDialog">Do you want a dialog box to be displayed or not?</param> 
/// <returns>false if the Battery is NOT in the critical state</returns> 
bool BatteryCritical(bool showDialog) { 
    _batteryAlert = false; 
    bool bad = false; // everything starts out ok. We are actually running, after all. 
    _batteryLevel = (BatteryLevel)SystemState.GetValue(SystemProperty.PowerBatteryStrength); 
    _batteryState = (BatteryState)SystemState.GetValue(SystemProperty.PowerBatteryState); 
    bool present = ((_batteryState & BatteryState.NotPresent) != BatteryState.NotPresent); 
    bool charging = ((_batteryState & BatteryState.Charging) == BatteryState.Charging); 
    bool critical = ((_batteryState & BatteryState.Critical) == BatteryState.Critical); 
    bool lowbatry = ((_batteryState & BatteryState.Low) == BatteryState.Low); 
    Color c; 
    if (present) { 
    if (charging) { 
     c = Color.Cyan; 
    } else { 
     if (critical) { 
     c = Color.Orange; 
     _batteryAlert = true; 
     } else if (lowbatry) { 
     c = Color.Yellow; 
     _batteryAlert = true; 
     } else { 
     c = Color.White; 
     } 
    } 
    } else { 
    c = Color.Silver; 
    } 
    StatusPanel.BackColor = c; 
    switch (_batteryLevel) { 
    case BatteryLevel.VeryHigh: // (81-100%) 
     BatteryPanel.BackColor = Color.Cyan; 
     break; 
    case BatteryLevel.High: // (61-80%) 
     BatteryPanel.BackColor = Color.Lime; 
     break; 
    case BatteryLevel.Medium: // 41-60%) 
     BatteryPanel.BackColor = Color.Yellow; 
     break; 
    case BatteryLevel.Low: // (21-40%) 
     BatteryPanel.BackColor = Color.Orange; 
     //WirelessUpdate(RadioState.Off, false); 
     break; 
    case BatteryLevel.VeryLow: // (0-20%) 
     BatteryPanel.BackColor = Color.Red; 
     //WirelessUpdate(RadioState.Off, false); 
     bad = (!charging && present); 
     break; 
    } 
    if (showDialog) { 
    string msg = string.Format("Level is {0}\r\nState is {1}", _batteryLevel, _batteryState); 
    if (_batteryLevel == BatteryLevel.Low) { 
     msg += "\r\n\r\nThe wireless radio will be inactive until it has been charged."; 
    } else if (bad == true) { 
     msg += "\r\n\r\nThis Application will now close to preserve the device. Please return it to a charging base immediately."; 
    } 
    MessageBox.Show(msg, "Battery Meter", MessageBoxButtons.OKCancel, MessageBoxIcon.None, 0); 
    } 
    if (!bad) { 
    StatusPanel.Refresh(); 
    // You could signal your app here 
    } else { 
    // Tell your app this device needs to turn off now. 
    } 
    return bad; 
} 

请给我一个upvote，如果它有帮助。

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