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; 
} 
} 
}