Limiting Input by Time of Day

Steven needs to ensure that nobody enters information into a worksheet between 4:00 pm and 6:30 pm each day. He wonders if it is possible to use Data Validation to prevent a user from entering information in a worksheet during a particular time each day.

There are two general ways you can go about this. One approach is to use Data Validation to check the time and either allow or disallow data entry.

1. Select all the cells in the worksheet.
2. Display the Data tab of the ribbon.
3. Click the Data Validation tool in the Data Tools group. Excel displays the Data Validation dialog box. (See Figure 1.)



Figure 1. The Data Validation dialog box.

4. Using the Allow drop-down list, choose Custom.
5. Enter the following in the Formula box:

       =OR(24*MOD(NOW(),1)<16,24*MOD(NOW(),1)>18.5)

6. Make changes on the Error Alert tab, as desired.
7. Click OK.

The problem with this approach is in the very first step: You need to select all the cells in the worksheet in order to prevent data being entered in any of them. Plus, if you already are using Data Validation in any of the cells, this approach will overwrite those settings.

For these reasons, it may be better to use a macro-based approach. All such approaches can utilize event handlers to check for any changes. The following relies on the Worksheet_Change event, which means it is triggered only when Excel detects a change in the worksheet.

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim sMsg As String

    sMsg = "No entries allowed between 4:00 pm and 6:30 pm!"
    If Time >= "4:00:00 PM" And Time <= "6:30:00 PM" Then
        MsgBox sMsg, vbCritical
        With Application
            .EnableEvents = False
            .Undo   ' This undoes the change the person made
            .EnableEvents = True
        End With
    End If
End Sub

Essentially, every time there is a change in the worksheet, the handler checks to see if it is between 4:00 pm and 6:30 pm. If it is, then a message box is displayed to indicate the error, and then the .Undo method is used to roll back any change that was attempted.

If you prefer, you could take a different approach and protect the worksheet if it is within the banned time:

Private Sub Worksheet_Activate()
     If Time >= "4:00:00 PM" And Time <= "6:30:00 PM" Then
        ActiveSheet.Protect
        MsgBox "Worksheet is protected."
    Else
        ActiveSheet.Unprotect
        MsgBox "You are free to edit now."
    End If
End Sub

The Worksheet_Activate event handler is invoked every time the worksheet is activated (selected). If the worksheet is activated anytime outside of the banned time, then it is unprotected. Of course, the user could still manually unprotect the worksheet even during the banned time, so it is a good idea to use this approach in conjunction with an approach that is triggered every time a change is attempted, as discussed earlier.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (13503) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, Excel in Microsoft 365, and 2021.