Background
Recently I answered a question which involved looking at a file's properties. Eventually the code I put up worked fine, but there is one thing about it that got me puzzled.
Problem
There are two specific lines where I wanted to replace a (to me what looks like) a string, with a variable, more specifically, try the following:
Sub TestForSO()
Dim oDir As Object: Set oDir = CreateObject("Shell.Application").Namespace("C:\Users\...\")
Debug.Print oDir.GetDetailsOf(oDir.Items, 1)
End Sub
Replace the pathname to a directory which includes an excel file, and it should return the property value just fine.
Now when I try to replace the full path with a variable the following throws an "Runtime Error 91: Object variable or with block variable not set" on the debug.print line:
Sub TestForSO()
Dim MainPath As String: MainPath = "C:\Users\...\"
Dim oDir As Object: Set oDir = CreateObject("Shell.Application").Namespace(MainPath)
Debug.Print oDir.GetDetailsOf(oDir.Items, 1)
End Sub
Solution
A bit peculiar to me that the following did work:
Sub TestForSO()
Dim MainPath As String: MainPath = "C:\Users\...\"
Dim oDir As Object: Set oDir = CreateObject("Shell.Application").Namespace(CStr(MainPath))
Debug.Print oDir.GetDetailsOf(oDir.Items, 1)
End Sub
I do not understand the difference per se as the code below will give the same result through "Watches":
Sub test()
Dim check1 As String, check2 As String
check1 = "Hello"
check2 = CStr("Hello")
End Sub
Question
Does somebody understand why the string variable on itself was not enough and would throw an error? Why would adding Cstr() make the code work when seemingly it's the same data type?
According to documentation about Namespace, it needs a parameter that must be a Variant or can be a string that specifies the path of the folder.
That explains why these 2 methods work with no problems:
Set oDir = CreateObject("Shell.Application").Namespace("C:\Users\...\ 'string path
Or defining a Variant variable:
Dim MainPath As Variant: MainPath = "C:\Users\...\"
Dim oDir As Object: Set oDir = CreateObject("Shell.Application").Namespace(CStr(MainPath))
But defining MainPath as string causes error Runtime Error 91: Object variable or with block variable not set
OP found a solution. If MainPath declared as string, and combined with Cstr, the code works.
It's just a theory, but some unnoficial sources (not directly related to VBA) mention that Cstr converts the value to a variant with a subtype.
http://www.csidata.com/custserv/onlinehelp/vbsdocs/vbs89.htm
https://docs.oracle.com/cd/E57185_01/HFMAD/ch10s06s04s03.html
Actually, the official documentation it's kind of confusing, because at first lines it says:
Each function coerces an expression to a specific data type.
and later on it says
The function name determines the return type
But if we read carefully, there is also some important information like this:
"...In general, you can document your code using the data-type
conversion functions to show that the result of some operation
should be expressed as a particular data type rather than the
default data type..."
And also:
"...This technique is consistent with the conversion of all other
intrinsic types to their equivalent Variant subtypes..."
So after doing some research and thinking about it in the last 24 hours, and reading a lot of times the previous paragraphs I've posted, I would dare to say that all conversion functions returns a Variant with a subtype. In this case, CStr does return a Variant that is being coerced to be expressed as string being string the subtype, but the data is Variant.
That would explain why doing Cstr(MainPath) makes the code works.
Related
Pardon me as am a newbie in VBA.
Sometimes I use
Dim r as Range
r = Range("A1")
Other times I use
Set r = Range("A1")
What is the difference? And when should I use what?
There's no reason to use set unless referring to an object reference. It's good practice to only use it in that context. For all other simple data types, just use an assignment operator. It's a good idea to dim (dimension) ALL variables however:
Examples of simple data types would be integer, long, boolean, string. These are just data types and do not have their own methods and properties.
Dim i as Integer
i = 5
Dim myWord as String
myWord = "Whatever I want"
An example of an object would be a Range, a Worksheet, or a Workbook. These have their own methods and properties.
Dim myRange as Range
Set myRange = Sheet1.Range("A1")
If you try to use the last line without Set, VB will throw an error. Now that you have an object declared you can access its properties and methods.
myString = myRange.Value
Dim declares the variable.
Dim r As Range
Set sets the variable to an object reference.
Set r = Range("A1")
However, I don't think this is what you're really asking.
Sometimes I use:
Dim r as Range
r = Range("A1")
This will never work. Without Set you will receive runtime error #91 Object variable or With block variable not set. This is because you must use Set to assign a variables value to an object reference. Then the code above will work.
I think the code below illustrates what you're really asking about. Let's suppose we don't declare a type and let r be a Variant type instead.
Public Sub test()
Dim r
debug.print TypeName(r)
Set r = Range("A1")
debug.print TypeName(r)
r = Range("A1")
debug.print TypeName(r)
End Sub
So, let's break down what happens here.
r is declared as a Variant
`Dim r` ' TypeName(r) returns "Empty", which is the value for an uninitialized variant
r is set to the Range containing cell "A1"
Set r = Range("A1") ' TypeName(r) returns "Range"
r is set to the value of the default property of Range("A1").
r = Range("A1") ' TypeName(r) returns "String"
In this case, the default property of a Range is .Value, so the following two lines of code are equivalent.
r = Range("A1")
r = Range("A1").Value
For more about default object properties, please see Chip Pearson's "Default Member of a Class".
As for your Set example:
Other times I use
Set r = Range("A1")
This wouldn't work without first declaring that r is a Range or Variant object... using the Dim statement - unless you don't have Option Explicit enabled, which you should. Always. Otherwise, you're using identifiers that you haven't declared and they are all implicitly declared as Variants.
Dim: you are defining a variable (here: r is a variable of type Range)
Set: you are setting the property (here: set the value of r to Range("A1") - this is not a type, but a value).
You have to use set with objects, if r were a simple type (e.g. int, string), then you would just write:
Dim r As Integer
r=5
Dim simply declares the value and the type.
Set assigns a value to the variable.
If a variable is defined as an object e.g. Dim myfldr As Folder, it is assigned a value by using the keyword, "Set".
Dim is short for Dimension and is used in VBA and VB6 to declare local variables.
Set on the other hand, has nothing to do with variable declarations. The Set keyword is used to assign an object variable to a new object.
Hope that clarifies the difference for you.
According to VBA help on SET statement it sets a reference to an object.so if you change a property the actual object will also changes.
Dim newObj as Object
Set var1=Object1(same type as Object)
Set var2=Object1(same type as Object)
Set var3=Object1(same type as Object)
Set var4=Object1(same type as Object)
Var1.property1=NewPropertyValue
the other Vars properties also changes,so:
Var1.property1=Var2.property1=Var3.property1=Var4.property1=Object1.Property1=NewpropertyValue`
actualy all vars are the same!
Pardon me as am a newbie in VBA.
Sometimes I use
Dim r as Range
r = Range("A1")
Other times I use
Set r = Range("A1")
What is the difference? And when should I use what?
There's no reason to use set unless referring to an object reference. It's good practice to only use it in that context. For all other simple data types, just use an assignment operator. It's a good idea to dim (dimension) ALL variables however:
Examples of simple data types would be integer, long, boolean, string. These are just data types and do not have their own methods and properties.
Dim i as Integer
i = 5
Dim myWord as String
myWord = "Whatever I want"
An example of an object would be a Range, a Worksheet, or a Workbook. These have their own methods and properties.
Dim myRange as Range
Set myRange = Sheet1.Range("A1")
If you try to use the last line without Set, VB will throw an error. Now that you have an object declared you can access its properties and methods.
myString = myRange.Value
Dim declares the variable.
Dim r As Range
Set sets the variable to an object reference.
Set r = Range("A1")
However, I don't think this is what you're really asking.
Sometimes I use:
Dim r as Range
r = Range("A1")
This will never work. Without Set you will receive runtime error #91 Object variable or With block variable not set. This is because you must use Set to assign a variables value to an object reference. Then the code above will work.
I think the code below illustrates what you're really asking about. Let's suppose we don't declare a type and let r be a Variant type instead.
Public Sub test()
Dim r
debug.print TypeName(r)
Set r = Range("A1")
debug.print TypeName(r)
r = Range("A1")
debug.print TypeName(r)
End Sub
So, let's break down what happens here.
r is declared as a Variant
`Dim r` ' TypeName(r) returns "Empty", which is the value for an uninitialized variant
r is set to the Range containing cell "A1"
Set r = Range("A1") ' TypeName(r) returns "Range"
r is set to the value of the default property of Range("A1").
r = Range("A1") ' TypeName(r) returns "String"
In this case, the default property of a Range is .Value, so the following two lines of code are equivalent.
r = Range("A1")
r = Range("A1").Value
For more about default object properties, please see Chip Pearson's "Default Member of a Class".
As for your Set example:
Other times I use
Set r = Range("A1")
This wouldn't work without first declaring that r is a Range or Variant object... using the Dim statement - unless you don't have Option Explicit enabled, which you should. Always. Otherwise, you're using identifiers that you haven't declared and they are all implicitly declared as Variants.
Dim: you are defining a variable (here: r is a variable of type Range)
Set: you are setting the property (here: set the value of r to Range("A1") - this is not a type, but a value).
You have to use set with objects, if r were a simple type (e.g. int, string), then you would just write:
Dim r As Integer
r=5
Dim simply declares the value and the type.
Set assigns a value to the variable.
If a variable is defined as an object e.g. Dim myfldr As Folder, it is assigned a value by using the keyword, "Set".
Dim is short for Dimension and is used in VBA and VB6 to declare local variables.
Set on the other hand, has nothing to do with variable declarations. The Set keyword is used to assign an object variable to a new object.
Hope that clarifies the difference for you.
According to VBA help on SET statement it sets a reference to an object.so if you change a property the actual object will also changes.
Dim newObj as Object
Set var1=Object1(same type as Object)
Set var2=Object1(same type as Object)
Set var3=Object1(same type as Object)
Set var4=Object1(same type as Object)
Var1.property1=NewPropertyValue
the other Vars properties also changes,so:
Var1.property1=Var2.property1=Var3.property1=Var4.property1=Object1.Property1=NewpropertyValue`
actualy all vars are the same!
I am new to vba and totally lost in writing the above mentioned function in vba. Actually, I want to do the same thing I would do with the usual excel formula.
Update:
Based on the answer of Scott I have adjusted my code. Now I have a Type mismatch error. The Type of Mname by definition is a string. The values in the lookup Range (B18:B38) are (not exclusive) integer. Should I tell Excel to take them as a string? If yes, how?
Summary:
I have a range (D18:D38) where I want to chose a value from based on the row number determined by a match between a string Variable (Mname) and another range (B18:B38). The string Variable is determined by the name of a file in a folder.
My Problem is that I get the error message: 'Unable to get the match property of the worksheetfunction class'
Thanks for your help!
Sub Test()
Application.ScreenUpdating = False
Dim Mname As String
Set WSCockpit = ThisWorkbook.ActiveSheet
Dim strFileName As String
Dim strFolder As String: strFolder = WSCockpit.Range("D9").Value
Dim strFileSpec As String: strFileSpec = strFolder & "*.xls*"
strFileName = Dir(strFileSpec)
Do While Len(strFileName) > 0
Dim strFilePath As String: strFilePath = strFolder & strFileName
Mname = Mid(strFileName, 13, Len(strFileName) - 17)
Dim rw As Long
rw = Application.Match(Mname, WSCockpit.Range("B18:B38"), 0)
Dim VarImp As Boolean
VarImp = Application.WorksheetFunction.Index(WSCockpit.Range("D18:D38"), rw)
'some other task'
Loop
Application.DisplayAlerts = True
End Sub
Backup:
Sorry for the code being messy. I have no clue about the general rules for writing vba. Like mentioned before, my goal is to get the lookup running. The looked up value will be "TRUE" or "FALSE". Afterwards I will use this in order to determine whether the file found in the folder needs to be imported or not. If you have some other suggestions for my coding or for the task I want to perform, I would be glad to hear.
Break it into steps and also ensure the data you expect to find in the lookup is in indeed there. Meaning, check the value of Mname at run-time (via debugging code) and verify you can find it manually.
Lastly, use Application.Match instead.
Dim rw as Long
rw = Application.Match(Mname, WSCockpit.Range("B18:B38"),0)
Dim import as Boolean
import = Application.WorksheetFunction.Index(WSCockpit.Range("D18:D38"),rw)
I'm trying to extract a .CAB file using Excel VBA, but I'm getting the following error:
Run-time error '91': Object variable or With block variable not set
I usually get this when I forget to use Set with an Object, but I've checked for that.
All examples I can find are variations on this theme:
Private Function DeCab(vSource, vDest) As Long
Dim objShell, objFileSource, objFileDest As Object
Set objShell = CreateObject("Shell.Application")
Set objFileSource = objShell.Namespace(vSource)
Set objFileDest = objShell.Namespace(vDest)
Call objFileDest.MoveHere(objFileSource.Items, 4 Or 16) 'Fails here
Decab = objFileDest.Items.Count
End Function
It's not failing on the Set line, but it's setting both objFileSource and objFileDest to Nothing even though I've confirmed vSource and vDest exist.
To confirm it has nothing to do with the .CAB file, I've also tried it without setting objFileSource and checking the value of objFileDest after it's set. It still returns Nothing. Why would that be? I'm on Windows 7, 64-bit, running Office 2010.
Your parameters must be submitted as Variant, not String
Sub Tester()
Dim src, dest '<< works
'Dim src As String, dest As String '<< gives the error you see
src = "D:\temp\test.zip"
dest = "D:\temp\unzip"
DeCab src, dest
End Sub
https://msdn.microsoft.com/en-us/library/windows/desktop/bb774085(v=vs.85).aspx
Tim's answer is correct. I found an alternative, as well:
Private Function DeCab(vSource, vDest) As Long
Dim objShell, objFileSource, objFileDest As Object
Set objShell = CreateObject("Shell.Application")
Set objFileSource = objShell.Namespace((vSource)) '<-extra parentheses
Set objFileDest = objShell.Namespace((vDest)) '<-extra parentheses
Call objFileDest.MoveHere(objFileSource.Items, 4 Or 16) 'Fails here
Decab = objFileDest.Items.Count
End Function
When you place an object in parentheses in VBA, it returns the default value of the object. Apparently, objShell.Namespace can't handle a pointer. It can only handle a string literal. Changing the signature to the following also works if you're passing in Strings:
Private Function DeCab(ByVal vSource, ByVal vDest) As Long
for my case. i used the shell
Set oShell = CreateObject("Shell.Application")
x= oShell.xxxx
y= oShell.Namespace(x)
in two different lines. seems like i'll need to re initialized to able to use on second line. eg
Set oShell = CreateObject("Shell.Application")
x= oShell.xxxx
y= CreateObject("Shell.Application").Namespace(x)
then only it works.
I found this function on a web
Private Function FileFolderExists(strFullPath As String) As Boolean
On Error GoTo EarlyExit
If Not Dir(strFullPath, vbDirectory) = vbNullString then
FileFolderExists = True
End If
EarlyExit:
On Error GoTo 0
End Function
And I want to pass string variable like this
Dim lineText As String
...
ElseIf FileFolderExists(lineText) = False Then
I am getting compile error "byref argument type mismatch"
When I put byval before strFullPath, it doesn't seem to work properly.
I also tried playing with Dir function, it works if I pass literal like "C:\test", but it doesn't work if I pass the variable.
Does anyone have function that check for folder existence and accepts the string variable as parameter ?
Thanks in advance
The problem seems to be that Word adds CR character to every paragraph, or, to be more exact, that the Text property of the Paragraph object returns the paragraph text plus the CR character.
AFAIK, this is the Word's behaviour for every paragraph, even for the last one.
How can this cause a compile error, I do not have a clue. If I take Milan's example:
Private Sub FirstLineFolder()
Dim lineText As String
lineText = ActiveDocument.Paragraphs(1).Range.Text
lineText = Left(lineText, Len(lineText) - 1) 'see below
MsgBox DoesFolderExist("C:\")
MsgBox DoesFolderExist(lineText)
End Sub
it returns true, true if the first line of the document is a valid folder. If I comment the marked line, the program still compiles and runs and returns true, false (with the same document).
There is some info about it on MSDN website
Try this:
Function FolderExists(folderPath As String) As Boolean
Dim f As Object
Set f = CreateObject("Scripting.FileSystemObject")
On Error GoTo NotFound
Dim ff As Object
Set ff = f.GetFolder(folderPath)
FolderExists = True
Exit Function
NotFound:
FolderExists = False
On Error GoTo 0
End Function
I used the following to test it:
Sub Tst()
Dim b As Boolean
Dim s As String
s = "c:\temp"
b = FolderExists(s)
End Sub
And it works as expected.
Generally, I used Scripting.FileSystemObject for all file-related operation in VBA, the native functions are too cumbersome.
It should be also noted that my function all checks for folders, while the original function -- judging by its name -- perhaps also tried to check for existence of files.
New code, it explains exactly what I need, it should be easier for you to try.
I am expecting folder in first line of the Word document, then I have to check if it exists.
Private Sub FirstLineFolder()
Dim lineText As String
lineText = ActiveDocument.Paragraphs(1).range.Text
MsgBox DoesFolderExists("C:\") ' this works
MsgBox DoesFolderExists(lineText) ' this doesnt work, when same folder passed
End Sub
Both my and Martin's function are throwing compiling error I wrote in my first post.
If it matters : Word is 2010, "option explicit" isn't written (I inherited the code, I can't change that)