Win CE 5.0 增加电池电量显示

摘自 http://blog.csdn.net/li0531/article/details/8818243

同时只在右上角显示一个 Label 控件，因此代码量精简了很多。

[DllImport("coredll")]
private static extern int GetSystemPowerStatusEx(SYSTEM_POWER_STATUS_EX lpSystemPowerStatus, bool fUpdate);
[DllImport("coredll")]
public static extern void SystemIdleTimerReset();
private SYSTEM_POWER_STATUS_EX status = new SYSTEM_POWER_STATUS_EX(); /// <summary>
///// 是否充电状态
///// </summary>
//private State AState = State.Normal;
/// <summary>
/// 电池当前状态 Charge：充电中；UnderCharge：电量不足；Normal：电池正常使用.
/// </summary>
public enum State
{
    /// <summary>
    /// 充电中
    /// </summary>
    Charge,
    /// <summary>
    /// 充电不足
    /// </summary>
    UnderCharge,
    /// <summary>
    /// 正常状态
    /// </summary>
    Normal,
    /// <summary>
    /// 充电完成
    /// </summary>
    ChargeFinally
};
private class SYSTEM_POWER_STATUS_EX
{
    public byte ACLineStatus = ;
    public byte BatteryFlag = ;
    public byte BatteryLifePercent = ;
    public byte Reserved1 = ;
    public uint BatteryLifeTime = ;
    public uint BatteryFullLifeTime = ;
    public byte Reserved2 = ;
    public byte BackupBatteryFlag = ;
    public byte BackupBatteryLifePercent = ;
    public byte Reserved3 = ;
    public uint BackupBatteryLifeTime = ;
    public uint BackupBatteryFullLifeTime = ;
}

/// <summary>
/// 创建电源指示
/// </summary>
private void GetBatteryState()
{
    if (GetSystemPowerStatusEx(status, false) == )
    {
        if (status.BatteryLifePercent >= )
        {
            labBattery.Text = "";
            labBattery.ForeColor = Color.Green;
        }
        else if (status.BatteryLifePercent <= )
        {
            if (status.ACLineStatus == )
                labBattery.Text = status.BatteryLifePercent.ToString() + " +";
            else
                labBattery.Text = "! " + status.BatteryLifePercent.ToString();
            labBattery.ForeColor = Color.Red;
        }
        else
        {
            labBattery.Text = status.BatteryLifePercent.ToString() + (status.ACLineStatus ==  ? " +" : "");
            labBattery.ForeColor = Color.Blue;
        }
    }
}

我是在 Timer 控件下以 10m 的频率调用这个方法的。