C#检测网络的连接状态

1. 方法定义 

[DllImport("wininet.dll")] 

private extern static bool InternetGetConnectedState( out int connectionDescription, int reservedValue ) ;

2. 方法说明 
参数: 

connectionDescription : 连接说明 

reservedValue : 保留值 
返回值: 

true: On Line 

false: Off Line 

3. 调用方法 

a. 你必须在你的code里引用System.Runtime.InteropServices,否则,会有编译错误 

b. 定义一个变量 int I = 0; 

c. 调用bool state = InternetGetConnectedState(out I,0);

完整的代码: 

using System.Runtime.InteropServices; 

namespace internet 

{ 

public class Class1 

{ 

[DllImport("wininet.dll")] 

private extern static bool InternetGetConnectedState( out int connectionDescription, int reservedValue ) ; 

public Class1(){} 

private bool IsConnected() 

{ 

int I=0; 

bool state = InternetGetConnectedState(out I,0); 

return state; 

} 

} 

}