Question

我在vba中编写了一些代码，以便在某些网站中找到某些名称的某些身份。如果所有内容都正确，那么代码运行良好，我的意思是如果链接有效，名称与a标签匹配，最后正则表达式可以找到标识。如果三个或所有三个中的任何一个都是错误的搜索，则脚本会抛出错误。我已经在下面的脚本中指定了发生错误的位置。

我希望专家为我提供任何解决方案，以便我能够处理错误并让我的脚本继续运行，直到所有链接都用完为止。

由于我对VBA知之甚少，所以我尝试使用On error resume next来跳过错误。然而，当我看一下结果时，结果却是一个明显的混乱。我正在粘贴一个粗略的例子，当我使用On error resume next时，我得到了什么。

Sub Identity_Finder()

    Dim http As New XMLHTTP60, html As New HTMLDocument
    Dim post As Object, link As Variant, refined_links As String
    Dim rxp As New RegExp, identity As Object

    For Each link In [{"http://spltech.in/","http://www.unifrostindia.com/","http://www.unitfrostindia.com/","http://www.greenplanet.in/"}]
        With http
            .Open "GET", link, False
            .send                    '''throws here the first error if the link is invalid
            html.body.innerHTML = .responseText
        End With

        For Each post In html.getElementsByTagName("a")
            If InStr(post.innerText, "certain_name") > 0 Then refined_links = post.href: Exit For
        Next post

        With http
            .Open "GET", refined_links, False
            .send                          ''throws another error here if no such link is found
        End With

        With rxp
            .Pattern = "some_regex"
            .Global = True
            Set identity = .Execute(http.responseText) 
        End With

        r = r + 1: Cells(r, 1) = link
        Cells(r, 2) = identity(0)    ''''throws another error here if no such identity is noticed

    Next link
End Sub

使用On error resume next我得到了什么：

John executive
Mac lawyer
lulu lawyer
Robin lawyer 
Cathy student

预期产出：

John executive
Mac lawyer
lulu 
Robin  
Cathy student

当我使用On error resume next时，空字段（当找不到它们时）会填充先前的值。我怎样才能解决这个误导性的结果？提前谢谢。

Answer 1

VBA中error trap的最有效方式是

1）实际测试输入/结果，然后通过定制函数或内置编码概念或两者兼而有之。

2）如果绝对需要，请使用VBA内置错误处理

示例1

例如。您可以使用自定义函数包装此语句，以测试URL是否有效。

With http
    .Open "GET", link, False
    .send                    '''throws here the first error if the link is invalid
    html.body.innerHTML = .responseText
End With

If ValidURL Then 

    With http
        .Open "GET", link, False
        .send     
         html.body.innerHTML = .responseText
    End With

End If

其中ValidURL是定义为：

的函数

Function ValidURL(URL as String) as Boolean

     Dim result as Boolean
    'I don't know how you would specify a valid link in your specific case
    'but that code goes here
    'a dummy example follows
     result = Left(URL,7) = "http://"
     ValidURL = result 'True or False

End Function

示例2

我在这个陈述中假设：

    With http
        .Open "GET", refined_links, False
        .send                          ''throws another error here if no such link is found
    End With

当找不到这样的链接时会产生特定的错误号（代码）。发现该号码并使用此代码绕过。

With http
    .Open "GET", refined_links, False
    On Error Resume Next
    .Send
    On Error GoTo 0
End With

If err.Number <> 9999 'replace with correct number

    'continue with regex test

End If

全力以赴

最后将所有内容放在一起，您可以这样构建，只需最少使用On Error Resume Next和GoTo语句。

For Each link In [{"http://spltech.in/","http://www.unifrostindia.com/","http://www.unitfrostindia.com/","http://www.greenplanet.in/"}]

    If ValidURL(link) Then 

        With http
            .Open "GET", link, False
            .send     
             html.body.innerHTML = .responseText
        End With

        For Each post In html.getElementsByTagName("a")
            If InStr(post.innerText, "certain_name") > 0 Then refined_links = post.href: Exit For
        Next post

        With http
            .Open "GET", refined_links, False
            On Error Resume Next
            .Send
            On Error GoTo 0
        End With

        If err.Number <> 9999 'replace with correct number

            With rxp
                .Pattern = "some_regex"
                .Global = True
                Set identity = .Execute(http.responseText) 
            End With

            'i will leave it to you on how to account for no pattern match
            r = r + 1: Cells(r, 1) = link
            Cells(r, 2) = identity(0)    ''''throws another error here if no such identity is noticed

        End If

    End If

Next link

如何有效地处理错误以防止误导结果？

1 个答案: