在Windows Mobile设备上，控制设备的无线电电源状态是一项重要的功能，特别是在需要优化设备性能或节省电池时。本文将介绍如何使用C#和VB.NET编程语言来实现这一功能。
在C#中，首先定义了一个枚举类型DevicePowerState，它包含了设备可能的电源状态。然后，使用P/Invoke调用了Windows核心DLL库中的两个函数：DevicePowerNotify和SetDevicePower，这两个函数用于通知系统设备电源状态的变化，并设置设备电源状态。
以下是C#实现的代码示例：
public enum DevicePowerState : int
{
Unspecified = -1,
FullPower = 0,
LowPower,
Standby,
Sleep,
Off
}
private const int POWER_NAME = 0x00000001;
[DllImport("coredll.dll", SetLastError = true)]
private static extern int DevicePowerNotify(string deviceId, DevicePowerState state, int flags);
[DllImport("coredll.dll", SetLastError = true)]
private static extern int SetDevicePower(string deviceId, int flags, DevicePowerState state);
public static void SetRadioPowerStatus(DevicePowerState state)
{
String key = "{98C5250D-C29A-4985-AE5F-AFE5367E5006}\\SWLD246L1";
int i1 = DevicePowerNotify(key, state, POWER_NAME);
if (i1 == 0)
{
int i2 = SetDevicePower(key, POWER_NAME, state);
}
}
在这段代码中，SetRadioPowerStatus方法接受一个DevicePowerState枚举参数，表示要设置的电源状态。如果DevicePowerNotify调用成功（返回值为0），则继续调用SetDevicePower来实际设置电源状态。
VB.NET的实现与C#类似，也是通过定义枚举类型和使用P/Invoke调用相应的函数来控制电源状态。以下是VB.NET实现的代码示例：
Public Enum DevicePowerState As Integer
Unspecified = -1
FullPower = 0
LowPower
Standby
Sleep
Off
End Enum
Private Const POWER_NAME As Integer = &H1
Private Declare Function SetDevicePower Lib "coredll.dll" _
(ByVal deviceId As String, ByVal flags As Integer, ByVal state As DevicePowerState) As Integer
Private Declare Function DevicePowerNotify Lib "coredll.dll" _
(ByVal deviceId As String, ByVal state As DevicePowerState, ByVal flags As Integer) As Integer
Public Shared Sub SetRadioPowerStatus(ByVal state As DevicePowerState)
Dim key As String = "{98C5250D-C29A-4985-AE5F-AFE5367E5006}\SWLD246L1"
Dim i1 As Integer = DevicePowerNotify(key, state, POWER_NAME)
If i1 = 0 Then
Dim i2 As Integer = SetDevicePower(key, POWER_NAME, state)
End If
End Sub
在VB.NET代码中，同样定义了DevicePowerState枚举，并使用Declare Function语句声明了外部函数。SetRadioPowerStatus方法的逻辑与C#版本相同。