Question

以下代码给出了我的问题：

    def connect(self):
    self.chatlog['state'] = NORMAL
    self.chatlog.insert(END, ("===ATTEMPTING TO CONNECT TO SERVER\n"))
    self.chatlog['state'] = DISABLED
    self.chatlog.yview(END)
    try:
        s.connect((host,port))
        self.chatlog['state'] = NORMAL
        self.chatlog.insert(END, ("===CONNECTED TO SERVER\n"))
        self.chatlog['state'] = DISABLED
        self.chatlog.yview(END)
        self.conn=True
        print("Connected")

    except ConnectionRefusedError:
        self.chatlog['state'] = NORMAL
        self.chatlog.insert(END, ("===SERVER COULD NOT BE FOUND\n" + "===PLEASE MAKE SURE THE SERVER IS ON, AND YOU'RE CONNECTED TO THE NETWORK\n"))
        self.chatlog['state'] = DISABLED
        self.chatlog.yview(END)
    else:
        self.chatlog['state'] = NORMAL
        self.chatlog.insert(END, ("===THERE'S AN ERROR WITH THE PROGRAM\n" + "===PLEASE TURN IT OFF AND ON AGAIN\n"))
        self.chatlog['state'] = DISABLED
        self.chatlog.yview(END)

当我连接到服务器时，它都连接（“try”部分完成，打印声明发生）但是也会出现“else”部分。我似乎无法找到原因。有没有人知道造成这种情况的原因是什么？

编辑：我应该说当我删除“else：”部分时，它也可以正常工作。

Answer 1

我猜你在这里试图捕捉所有异常，但这不是正确的语法。

正确的方法是：

try:
   # do something dangerous
except ConnectionRefusedError:
   # handle known error
except:
   # handle unknown error

在这种情况下，

else表示如果没有错误发生，代码将被执行。

Answer 2

else块的try: except: else: finally:部分与else中的if: else:类似，有效：

if someerror:
    ...
else:
    ...

当{em>没有从else块中引发错误时，try块会运行。使用此块可以最小化try块中的代码;在你的情况下：

try:
    s.connect((host,port))           
except ConnectionRefusedError:
    self.chatlog['state'] = NORMAL
    self.chatlog.insert(END, ("===SERVER COULD NOT BE FOUND\n" + "===PLEASE MAKE SURE THE SERVER IS ON, AND YOU'RE CONNECTED TO THE NETWORK\n"))
    self.chatlog['state'] = DISABLED
    self.chatlog.yview(END)
else:
    self.chatlog['state'] = NORMAL
    self.chatlog.insert(END, ("===CONNECTED TO SERVER\n"))
    self.chatlog['state'] = DISABLED
    self.chatlog.yview(END)
    self.conn=True
    print("Connected")

尝试和除了返回错误，但是当没有运行时，没有错误发生？

2 个答案: