Bacon Bits: » Worksheet Protection

Automatically Unprotect Sheets Based on Domain Name

datapig — Wed, 13 Apr 2011 09:16:26 +0000

POLO (one of my 12 fans) asks a question:

"I want to control read and write access to an Excel file using either windows logins or a list in Excel. Like match userid to the list in Excel and then give either write or read only access to the spreadsheet. Is it possible?"

The answer is yes. You can capture a user's Windows Domain\UserName (see my previous post on this) and throw that against a list in Excel to determine permissions and views.

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In this scenario, your sheets would be protected by default, rendering them read only. Meaning, you would apply worksheet protection so that your sheets are protected when the file opens. The idea is to have Excel automatically unlock the sheet protection only for those who are in a list of authorized Read/Write users.

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Step 1: Create a list of Domain\Usernames for those individuals who are Read/Write users. The values in this list will have to be written exactly the way the domain names show up in your organization. Once completed, create a Named Range for this list. In this example, I've called my list "DomainList".

Step 2: Copy and paste this code into a standard module. This will allow you to get the users Domain\Username.

PLAIN TEXT

Visual Basic:

Function getReturnUName()

getReturnUName = Environ("UserDomain") & "\" & Environ("Username")

End Function

Step 3: In the Workbook's Open event, enter some code that will compare the user's domain information (via the getReturnUName function you just created) to your DomainList. If there is a match, then you can unprotect the appropriate sheets – making them read/write.

Step 4: Of course, you'll want to ensure the workbook re-protects the sheets before closing. So in the Workbook's BeforeClose event, enter some code to protect the appropriate sheets.

Well that's pretty much it. You now have a smart workbook that automatically detects the user and unprotects if the user in in special read/write list.

Notes:

1. You'll want to protect the VBA Modules, hiding the code. (From within the VBE go to Tools>VBAProject Properties and then click the Protection page tab and then check "Lock project from viewing" and then enter your password and again to confirm it.)

2. You'll probably want to hide the sheet that contains your DomainList.

3. I don't have to tell you that this technique is far from a hacker proof system of managing permissions. At best, it's a way to allow your 'Admin' users to work with the workbook without constantly having to enter passwords.

Next week, I'll show you how to use a similar technique to automatically hide and unhide certain sheets based on each individual user.

Worksheet Protection Best Practice

datapig — Thu, 26 Aug 2010 10:22:47 +0000

I was reviewing someone's workbook the other day way I saw some code similar to this:

Sheets("Sheet1").Unprotect Password:="MeatFace"
PROCEDURE
Sheets("Sheet1).Protect Password:=" MeatFace "

This code unprotects the sheet, runs a procedure, and then protects the sheet again. The reason this guy wrapped his procedure with Unprotect/Protect is because his procedure changes a worksheet in some way. And you cannot run a macro that changes a worksheet while that worksheet is protected.

Now, I'll bet a bunch of you still wrap your procedures with Unprotect/Protect. So I'm here to tell you that although this technique does work, it does have a couple of drawbacks. First, if the code in the middle errors out, then your sheet won't become protected again. Second, every procedure (that changes the worksheet) would need to be wrapped in your UnProtect/Protect statements. This obviously leads to redundant code which could be difficult to manage.

A better way is to protect your worksheet with the optional UserIntefaceOnly argument.

Place this code in the Workbook Open event:

When you set the UserInterfaceOnly argument to True, you tell Excel that the worksheet protection does not apply to macros. This will allow your macros to run without having to constantly protect and unprotect your worksheet.

Bonus Tip - Free of Charge

There are other arguments (similar to UserInterfaceOnly) that can help better define what happens when you protect your worksheet.

For example, if I wanted to protect my worksheet, but still allow my customers to Enable/Disable Autofilters, I would add the AllowFiltering argument:

Sub ProtectSheet()
Sheets("Sheet1").Protect _
Password:="MyPassword", _
AllowFiltering:=True
End Sub

Here is a list of the arguments you can leverage – painstakingly copied and pasted from Excel help.

DrawingObjects	True to protect shapes. The default value is True.
Contents	True to protect contents. For a chart, this protects the entire chart. For a worksheet, this protects the locked cells. The default value is True.
Scenarios	True to protect scenarios. This argument is valid only for worksheets. The default value is True.
UserInterfaceOnly	True to protect the user interface, but not macros. If this argument is omitted, protection applies both to macros and to the user interface.
AllowFormattingCells	True allows the user to format any cell on a protected worksheet. The default value is False.
AllowFormattingColumns	True allows the user to format any column on a protected worksheet. The default value is False.
AllowFormattingRows	True allows the user to format any row on a protected. The default value is False.
AllowInsertingColumns	True allows the user to insert columns on the protected worksheet. The default value is False.
AllowInsertingRows	True allows the user to insert rows on the protected worksheet. The default value is False.
AllowInsertingHyperlinks	True allows the user to insert hyperlinks on the worksheet. The default value is False.
AllowDeletingColumns	True allows the user to delete columns on the protected worksheet, where every cell in the column to be deleted is unlocked. The default value is False.
AllowDeletingRows	True allows the user to delete rows on the protected worksheet, where every cell in the row to be deleted is unlocked. The default value is False.
AllowSorting	True allows the user to sort on the protected worksheet. Every cell in the sort range must be unlocked or unprotected. The default value is False.
AllowFiltering	True allows the user to set filters on the protected worksheet. Users can change filter criteria but can not enable or disable an auto filter. Users can set filters on an existing auto filter. The default value is False.
AllowUsingPivotTables	True allows the user to use pivot table reports on the protected worksheet. The default value is False.

Hack into a protected Excel 2007 Sheet

datapig — Fri, 18 Sep 2009 06:40:27 +0000

When Microsoft introduced Excel 2007, they introduced new file types - we all know them by now: xlsx, xlsm, xltx, etc. These file types are often referred to as Open XML. That's because the new file types are essentially packages that contain XML files. If you take an xlsx file and change the extension to zip, you'll be able to see all the xml documents that make up your Excel file.

The new Open XML file types come with lots of benefits. One of the major benefits is that you can change the content and properties of an Excel 2007 file simply by manipulating the XML documents that make it up.

Well, while playing with the Open XML files, I discovered that you can remove spreadsheet protection simply by applying a simple edit to the xml within the Excel file.

Say I have a workbook where Sheet1 is password protected. So I think to myself, "the nerve of some people - trying to keep me out of their spreadsheet".

I decide that I want to unprotect this sheet, but I don't know the password. Because this is Excel 2007, I'll hack into the xml and remove the spreadsheet protection.

Step 1: Make a backup of your file in case you really monkey it up.

Step 2: Change the file extension to zip.

Step 3: Extract the contents of the zip file.

Step 4: Go to the extracted files and navigate to the xml for the target sheet (found in the 'xl\worksheets' directory)

Step 5: Open the target sheet's xml document using an XML editor (I use a free editor called XML Marker)

Step 6: Find the 'sheetProtection' tag and remove the entire line.

Step 7: Save the edited xml document and replace the old xml document found in the original zip file.

Step 8: Change the extension back to xlsx.

Step 9: Enjoy your unprotected sheet.

That's right folks; simply removing the sheetProtection element from the xml part negates all protections placed on that sheet. Amazing, right?

A couple of notes:

Any password you see in the XML file is not the real password, nor will it work if you try to use it. It's worthless.
Unfortunately, it doesn't seem as though you can unprotect an entire workbook this way. Something prevents you from even opening the Open XML package for a protected Workbook.
Do I have to even mention that this doesn't apply to any xls files?
Of course, you could do this all programmatically, but this strikes me as a one-off kind of thing. So coding something up is just not worth it to me.

Protect Worksheet Structure with Array Formulas

datapig — Fri, 31 Jul 2009 14:36:25 +0000

In the another display of passive aggressive behavior, I want to show you a trick you can use to prevent anyone from adding or deleting rows or columns by using a simple array formula.

I'm pretty sure I got this trick from Bob Umlas. Most Bob tricks, they are extremely cool, but I never seem to find situations where I can use them. But, maybe this trick will hit the spot for some of you.

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Step 1: Highlight the rows where you don't rows added or deleted.

Type =""

Press Shift+Ctrl+Enter to apply the array.

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Step 2: Highlight the columns where you don't rows added or deleted.

Type =""

Press Shift+Ctrl+Enter to apply the array.

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Step 3: Hide the array formulas along with anything else you don't want your users to see.

When your users try to add or delete a column or row in the protected area, they'll get a face full of error message.

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I think this would be useful if you didn't want apply sheet protection but still wanted to prevent structural changes. Although - I can't think of any reason why you would stay away from sheet protection.

What do you think?

Limiting Movement within Your Worksheet

datapig — Tue, 14 Jul 2009 03:42:01 +0000

It's always fun to be passive aggressive toward your users.

Here's a new way to exert your impotent rage on the power user who's always doing wonky things to your spreadsheets.

You can limit navigation to a certain range of cells. Here's how:

Step 1: Press Alt+F11 to get to the Visual Basic Editor

Step 2: Choose the sheet you're working with.

Step 3: Activate the Properties for that sheet by clicking View -> Properties Window

Step 4: In the 'ScrollArea' property, enter the range in which you would like to limit scrolling.

Once you've implemented a limit, your users will not be able to navigate outside the set boundaries.

You can also apply this via VBA.

To really make them feel like a monkey, you can hide the off limit columns.

This way, they get a safe little 'play area' where mummy and daddy can watch them closely.