向知识井致以问候......
我一直在阅读有关此特定错误的大量帖子，但未发现任何可解决我特定问题的内容。
我在Access 2010前端中有一些VBA代码。有时，但并非总是如此，我得到一个“对象变量或未设置块变量”。错误。我的代码如下：
Public Sub ValidateAddress(PassedAddress As Object, PassedCity As Object, PassedState As Object, _
PassedZIP As Object, PassedCongressionalDistrict As Object, PassedValidated As Object, HomeForm As Form)
On Error GoTo ShowMeError
Dim strUrl As String ' Our URL which will include the authentication info
Dim strReq As String ' The body of the POST request
Dim xmlHttp As New MSXML2.XMLHTTP60
Dim xmlDoc As MSXML2.DOMDocument60
Dim dbs As Database
Dim candidates As MSXML2.IXMLDOMNode, candidate As MSXML2.IXMLDOMNode
Dim components As MSXML2.IXMLDOMNode, metadata As MSXML2.IXMLDOMNode, analysis As MSXML2.IXMLDOMNode
Dim AddressToCheck As Variant, CityToCheck As Variant, StateToCheck As Variant, ZIPToCheck As Variant
Dim Validated As Boolean, District As Variant, MatchCode As Variant, Footnotes As Variant
Dim candidate_count As Long, SQLCommand As String, Start, Finish
' This URL will execute the search request and return the resulting matches to the search in XML.
strUrl = "https://api.smartystreets.com/street-address/?auth-id=<my_auth_id>" & _
"&auth-token=<my_auth_token>"
AddressToCheck = PassedAddress.Value
CityToCheck = PassedCity.Value
StateToCheck = PassedState.Value
If Len(PassedZIP) = 6 Then ZIPToCheck = Left(PassedZIP.Value, 5) Else ZIPToCheck = PassedZIP.Value
' Body of the POST request
strReq = "<?xml version=""1.0"" encoding=""utf-8""?>" & "<request>" & "<address>" & _
" <street>" & AddressToCheck & "</street>" & " <city>" & CityToCheck & "</city>" & _
" <state>" & StateToCheck & "</state>" & " <zipcode>" & ZIPToCheck & "</zipcode>" & _
" <candidates>5</candidates>" & "</address>" & "</request>"
With xmlHttp
.Open "POST", strUrl, False ' Prepare POST request
.setRequestHeader "Content-Type", "text/xml" ' Sending XML ...
.setRequestHeader "Accept", "text/xml" ' ... expect XML in return.
.send strReq ' Send request body
End With
' The request has been saved into xmlHttp.responseText and is
' now ready to be parsed. Remember that fields in our XML response may
' change or be added to later, so make sure your method of parsing accepts that.
' Google and Stack Overflow are replete with helpful examples.
Set xmlDoc = New MSXML2.DOMDocument60
If Not xmlDoc.loadXML(xmlHttp.ResponseText) Then
Err.Raise xmlDoc.parseError.errorCode, , xmlDoc.parseError.reason
Exit Sub
End If
' According to the schema (http://smartystreets.com/kb/liveaddress-api/parsing-the-response#xml),
' <candidates> is a top-level node with each <candidate> below it. Let's obtain each one.
Set candidates = xmlDoc.documentElement
' First, get a count of all the search results.
candidate_count = 0
For Each candidate In candidates.childNodes
candidate_count = candidate_count + 1
Next
Set candidates = xmlDoc.documentElement
Select Case candidate_count
Case 0 ' Bad address cannot be corrected. Try again.
Form_frmPeople.SetFocus
MsgBox "The address supplied does not match a valid address in the USPS database. Please correct this.", _
vbOKOnly, "Warning"
PassedAddress.BackColor = RGB(255, 0, 0)
PassedCity.BackColor = RGB(255, 0, 0)
PassedState.BackColor = RGB(255, 0, 0)
PassedZIP.BackColor = RGB(255, 0, 0)
Exit Sub
Case 1 ' Only one candidate address...use it and return.
For Each candidate In candidates.childNodes
Set analysis = candidate.selectSingleNode("analysis")
PassedAddress.Value = candidate.selectSingleNode("delivery_line_1").nodeTypedValue
Set components = candidate.selectSingleNode("components")
PassedCity.Value = components.selectSingleNode("city_name").nodeTypedValue
PassedState.Value = components.selectSingleNode("state_abbreviation").nodeTypedValue
PassedZIP.Value = components.selectSingleNode("zipcode").nodeTypedValue & "-" & _
components.selectSingleNode("plus4_code").nodeTypedValue
Set metadata = candidate.selectSingleNode("metadata")
PassedCongressionalDistrict.Value = CInt(metadata.selectSingleNode("congressional_district").nodeTypedValue)
PassedValidated.Value = True
Next
Exit Sub
Case Else ' Multiple candidate addresses...post them and allow the user to select.
DoCmd.SetWarnings False
Set dbs = CurrentDb
If IsTableQuery("temptbl") Then dbs.Execute "DROP TABLE temptbl"
dbs.Execute "CREATE TABLE temptbl (Selected BIT, CandidateAddress CHAR(50), CandidateCity CHAR(25), _
CandidateState CHAR(2), CandidateZIP CHAR(10), CandidateCongressionalDistrict INTEGER, _
MatchCode CHAR(1), Footnotes CHAR(30));"
DoCmd.SetWarnings True
Start = Timer
Do While Timer < Start + 1
DoEvents
Loop
For Each candidate In candidates.childNodes
Set components = candidate.selectSingleNode("components")
AddressToCheck = candidate.selectSingleNode("delivery_line_1").nodeTypedValue
CityToCheck = components.selectSingleNode("city_name").nodeTypedValue
StateToCheck = components.selectSingleNode("state_abbreviation").nodeTypedValue
ZIPToCheck = components.selectSingleNode("zipcode").nodeTypedValue & "-" & _
components.selectSingleNode("plus4_code").nodeTypedValue
Set metadata = candidate.selectSingleNode("metadata")
District = metadata.selectSingleNode("congressional_district").nodeTypedValue
Set analysis = candidate.selectSingleNode("analysis")
MatchCode = analysis.selectSingleNode("dpv_match_code").nodeTypedValue
Footnotes = analysis.selectSingleNode("dpv_footnotes").nodeTypedValue
DoCmd.SetWarnings False
dbs.Execute "INSERT INTO temptbl ( CandidateAddress, CandidateCity, CandidateState, CandidateZIP, _
CandidateCongressionalDistrict, MatchCode, Footnotes ) " & vbCrLf & "SELECT """ & AddressToCheck & _
""" AS Expr1, """ & CityToCheck & """ AS Expr2, """ & StateToCheck & """ AS Expr3, """ & _
ZIPToCheck & """ AS Expr4, " & District & " AS Expr5, """ & MatchCode & """ AS Expr6, """ & _
Footnotes & """ AS Expr7;"
DoCmd.SetWarnings True
Next
DoCmd.OpenForm "frmPeopleAddressMaintenance"
Do Until CurrentProject.AllForms("frmPeopleAddressMaintenance").IsLoaded = False
DoEvents
Loop
HomeForm.SetFocus
If IsTableQuery("temptbl") Then dbs.Execute "DROP TABLE temptbl"
End Select
dbs.Close
Exit Sub
ShowMeError:
MsgBox Err.Description, vbOKOnly, "ERROR!"
End Sub
错误发生在两个特定的地方：
在“案例1”下：错误发生在...之后......
PassedCongressionalDistrict.Value = CInt(metadata.selectSingleNode("congressional_district").nodeTypedValue)
...被执行。我调试了这个并验证了语句是否正确执行以及“PassedCongressionalDistrict”对象的值是否正确。
然后，在“Case Else”下：For循环正确处理第一个项目列表，但在开始处理第二个项目时失败并显示已识别的错误，即使第二个项目中有良好合法的数据。
我希望我已经解释得这么好了。我似乎无法弄清楚（1）如何更充分地调试这个和（2）为什么发生错误，因为我似乎已经正确定义了所有的对象变量。
此致 肯
答案 0 :(得分：2)
几乎肯定是因为（有时）XML主体中没有名为“metadata”的子节点成员 - 所以当您尝试将“元数据”对象绑定到.selectSingleNode（）时方法它返回Nothing。您可以随时检查以确保它实际上已绑定...
'// ...start code snippet...
Set metadata = candidate.selectSingleNode("metadata")
If Not metadata is Nothing Then
PassedCongressionalDistrict.Value = CInt(metadata.selectSingleNode("congressional_district").nodeTypedValue)
End If
PassedValidated.Value = True
'// ...end code snippet...