Kingdz is changed to cainiao. A daily C # Small instance-C # determines whether the network is connected.

Today, writeCodeThere are few examples.ArticleHaha, but I still want to write it. Is it a cainiao? The change is complete. Hey. Today I found a friend's article interesting. Let's show you how

I finally know why China Mobile is better than China Unicom!
1. Right-click on the desktop and choose new-Text Document;
2. Open "New Text Document", enter "move", and save the disk and exit;
3. Open "New Text Document" again. What do you see?
4. Is the word "mobile" just entered?

Let's change it over:

1. Right-click on the desktop and choose new-Text Document;
2. Open "New Text Document", enter "Unicom", and save the disk and exit;
3. Open "New Text Document" again. What do you see?
4. Is the word "Unicom" just entered missing? Instead, it looks like a burning cell phone battery?

I only know why China Unicom is not so powerful today, haha. Okay. Let's get started with our small instance.

How can I use C # To determine whether the network is connected? There are n methods. We will try to explain them as completely as possible.

The first method is the simplest, but not accurate.

Private voidBtnisconnect_click (ObjectSender,EventargsE ){If(Systeminformation. Network ){MessageBox. Show ("Connected, but not sure whether it is Internet or LAN");}}
 

This method is also true under the LAN

 

The second method is to Ping An address, so we will adopt Baidu. If Baidu is down, wow, it will not blame anyone. Haha

First, reference the namespace

 
UsingSystem. net. networkinformation;
 

Then, let's simply implement it. This kind of implementation is not perfect, and we are gradually improving it,

Private voidBtnping_click (ObjectSender,EventargsE ){PingPing =NewPing();PingreplyPR = ping. Send ("Baidu.com");If(PR. Status = ipstatus. Success)MessageBox. Show ("Networking status");ElseMessageBox. Show ("Your network cable has fallen");}
 

 
Ping. Send ("Baidu.com"); remember that sending has eight overload methods. You can adjust them by yourself.
 

 
Let's get a Google IP address first.
 

 
Start now.
 

Here we mainly prepare our data based on the send parameter. Some people also refer to this as a heartbeat packet, which is to constantly send requests and determine whether the network is connected.
 

 
PingPing =NewPing();PingoptionsPoptions =NewPingoptions(); Poptions. dontfragment =True;StringData =String. Empty;Byte[] Buffer =Encoding. ASCII. getbytes (data );
 

Prepare data in place and start sending

 

IntTimeout = 1200;PingreplyReply = ping. Send (IPaddress. Parse ("74.125.71.104"), Timeout, buffer, poptions );If(Reply. Status = ipstatus. Success)MessageBox. Show ("Networking status");ElseMessageBox. Show ("Your network cable has fallen");
 

Haha, okay. Test it.

 
Hey, this is much more stable.
 

 
Of course, another way is to call the system API,
 

[Dllimport("Wininet")]Private extern static boolInternetgetconnectedstate (Out intConnectiondescription,IntReservedvalue );
 

 
The usage address of the above function is given.
 

 
Http://msdn.microsoft.com/en-us/library/windows/desktop/aa384702%28v=vs.85%29.aspx
 

 
IntI = 0;If(Internetgetconnectedstate (OutI, 0 ))MessageBox. Show ("Networking status");ElseMessageBox. Show ("Your network cable has fallen");
 

 
Haha. Someone in the previous instance asked about the verification code judgment method. Hey hey, there's a suspense. I'll give you an example to see the effect.
 

 
Code: isinternet.rar