Disable or Grey out Check box If Combo or Text Box Not Filled In

I don't know how many times I have to say that a Yes/No field can never be null (unless it comes from a nonexistent record in an outer join query).  If you are sure that Who_Was_Notified_Police is Null, then it is not a Yes/No field.

To treat Null the same as False, try using:

   If Nz(Who_Was_Notified_Police, False) Then

or

   If Not IsNull(Who_Was_Notified_Police) And Who_Was_Notified_Police = True Then

But, if Who_Was_Notified_Policeis not a Yes/No field, then that probably will not work either.

It may not be null but it isn't "no" if I don't specify "no" as the default value.  If I leave the default value blank the code I had errors out with the null error.  This goes for all the fields that are shown in my print screen with yes/no as the data type.  Both codes that you specified above does work.  I think the reason the if not isnull didn't work the first time because if you uncheck the box it actually isn't null or whatever it supposed to be since you say it can't be null and is no.  Since it is no it will still enable the other fields.  I needed the "and who_was_notified_police = true".  So the codes you gave me works, does that mean it isn't a yes/no data type?  If so how can this be if it is a yes/no data type in the table?

Do you know how I can take out data from a disabled control if box is unchecked?

Ahhh, you want to remove the value as well as disable the control.  That should be just a matter of setting it to Null:

    . . .

    Me.Who_Was_Notified_Police_Name.Enabled = True

  Else

    Me.Who_Was_Notified_Police_Name = Null

    Me.Who_Was_Notified_Police_Name.Enabled = False

  End If

Are you sure that the field for Who_Was_Notified_Police is not a Text field in the table?  It's sort of looking like it's either that or you are confusing the Format with the DataType.  Did you get the If statement to work?  If you did, what does it finally look like?

Here is the print screen to show you the field has a yes/no data type.  I took out the default value of "no" and used your nz code.  It now looks like this:

Private Sub Who_Was_Notified_Police_AfterUpdate()

If Nz(Who_Was_Notified_Police, False) Then

    Me.Who_Was_Notified_Police_Name.Enabled = True

    Me.Who_Was_Notified_Police_Date.Enabled = True

    Me.Who_Was_Notified_Police_Report_No.Enabled = True

    Me.Who_Was_Notified_Police_Name.SetFocus

  Else

    Me.Who_Was_Notified_Police_Name.Enabled = False

    Me.Who_Was_Notified_Police_Date.Enabled = False

    Me.Who_Was_Notified_Police_Report_No.Enabled = False

  End If

End Sub

I looked into the nz code and it is basically saying (correct me if I am wrong) that if the "Who_Was_Notified_Police" is null to return "false" and if not return the value of "Who_Was_Notified_Police". I don't understand how this still works if the answer is "no".  How does this code still know to disable the fields properly?  I ask this because to me, it doesn't seem to say enable the fields only when the "Who_Was_Notified_Police" is "true" and disable when "false".  I would've thought that you needed it to say something like "Who_Was_Notified_Police=who_was_notified_police_name and Nz(Who_Was_Notified_Police, False) somehow for when the value is null. The second code works too, but it actually works with just the "if Who_Was_Notified_Police = True" without the "If Not IsNull(Who_Was_Notified_Police)".  This second code seems to say only when the "Who_Was_Notified_Police" is "yes" or "true" or "-1" to enable me.who_was... fields, so if it is "no" "false" or "null" to disable and that one makes sense to me.  Sorry for so much questions, but I am just trying to understand these codes and how they work without just copying stuff you all help me with.  I appreciate all the time you all take to help us newbies.