VBA 返回“运行时错误 91：对象变量或块变量未设置”
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VBA returning "Run-time error 91: Object variable or With block variable not set"
提问by MartinUKPL
Ok, so I'm trying to make a complex geocoding script in VBA. I have written the following code and for some reason it returns an error ("Run-time error 91: Object variable or With block variable not set"). An example of a link that I use can be: "https://maps.googleapis.com/maps/api/geocode/xml?address=1+Infinite+Loop,+Cupertino,+Santa+Clara,+California+95014&sensor=false".
好的，所以我正在尝试在 VBA 中制作一个复杂的地理编码脚本。我编写了以下代码，由于某种原因，它返回一个错误（“运行时错误 91：对象变量或块变量未设置”）。我使用的链接示例可以是：“https://maps.googleapis.com/maps/api/geocode/xml?address=1+Infinite+Loop,+Cupertino,+Santa+Clara,+California+95014&sensor =假”。
Sub readXML(link As String)
Dim odc As DOMDocument
Dim lat As IXMLDOMElement
Dim lng As IXMLDOMElement
Set odc = New MSXML2.DOMDocument
odc.async = False
odc.Load (link)
lat = odc.SelectSingleNode("GeocodeResponse/result/geometry[location_type='ROOFTOP']/location/lat").Text
lng = odc.SelectSingleNode("GeocodeResponse/result/geometry[location_type='ROOFTOP']/location/lng").Text
Debug.Print lat & "; " & lng
End Sub
Can anyone tell me what I'm doing wrong?
谁能告诉我我做错了什么？
回答by Tomalak
SelectSingleNode()may return Nothing.
SelectSingleNode()可能会回来Nothing。
Never call a property (like .Text) on a function if the result of that function can be Nothing.
不要调用一个属性（比如.Text上的功能）如果函数的结果可以Nothing。
Do something like this to avoid this error:
执行以下操作以避免此错误：
Dim location As IXMLDOMElement
Dim locationPath As String
locationPath = "GeocodeResponse/result/geometry[location_type='ROOFTOP']/location"
Set location = odc.SelectSingleNode(locationPath)
lat = GetTextValue(location, "./lat")
lng = GetTextValue(location, "./lng")
' ------------------------------------------------------------------------
Function GetTextValue(node As IXMLDOMElement, Optional xpath As String = "") As String
Dim selectedNode As IXMLDOMElement
If xpath <> "" And Not node Is Nothing Then
Set selectedNode = node.SelectSingleNode(xpath)
Else
Set selectedNode = node
End If
If selectedNode Is Nothing Then
GetTextValue = ""
Else
GetTextValue = Trim(selectedNode.Text)
End If
End Function
回答by Kevin Pope
This always happens to me when I try to assign a value to an object without using set. Try this:
当我尝试在不使用set. 尝试这个：
Set lat = odc.SelectSingleNode("GeocodeResponse/result/geometry[location_type='ROOFTOP']/location/lat").Text
Set lng = odc.SelectSingleNode("GeocodeResponse/result/geometry[location_type='ROOFTOP']/location/lng").Text
回答by Brad Thomas
Why the spaces before /location/lat, and .Text on lng but not lat?
为什么 /location/lat 之前的空格和 lng 上的 .Text 而不是 lat？
