Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast Making Agile work for data science. Stack Gives Back Featured on Meta. New post summary designs on greatest hits now, everywhere else eventually. Linked 0. Related 0. Hot Network Questions. Question feed. Stack Overflow works best with JavaScript enabled.
Expand your skills. Get new features first. Was this information helpful? Yes No. Thank you! Any more feedback? The more you tell us the more we can help. Can you help us improve? Resolved my issue. Clear instructions. Easy to follow. No jargon. Pictures helped. Didn't match my screen. Incorrect instructions. Too technical. That means that even when opening the form and never assigning a value to the textbox, it's value is not Null.
Configuration of underlying tables cannot be the reason for this because the textbox is unbound. Some of the other contributors have mentioned that the default value of the textbox may change it's behaviour regarding Null values.
Initially, I could not believe that, but I decided to test this nevertheless. Now I am glad that I have done it. The result is very interesting: If I change the default value of the unbound! By the way, the result of the second comparison is what is expected; it is documented that the result of comparing a Null value with any other value will be Null.
A further test shows that the textbox keeps it's Null value even if it is assigned that value explicitely:. If an unbound textbox is assigned a default value of Null in the design view of the form, it can be programmatically assigned Null values and non-Null values during runtime and keeps these values like expected.
The same probably applies if the default value is set by code; I did not test this, though. I did not test what happens when another default value is set for the textbox.
But if the textbox is created without choosing a default value explicitely, the textbox cannot be assigned Null values during runtime. When doing so, the textbox will silently get a value of "" instead of Null. All this is really illogic and sucks, and it took us many hours to debug, and now we have to check every textbox in our application or change our code.
I could understand if an unset default value is interpreted differently in different versions of Access; it's a kind of philosophy if a property the user hasn't set is felt as being "" or as being Null. But that must not have any influence on what values can be assigned by code at runtime. But even when such an influence is existent, the runtime has to throw an error if we try to assign a value which the textbox cannot keep, instead of silently converting the assigned value to something else.
This is absolutely idiotic, and it has taken us many hours and will take may more whole days in the future. That is not correct. An unassigned value property is supposed to be null. What if the next version of Access decides that text fields of a record that do not have a default value should be assigned "" instead of null? You happen to be setting the textbox to null. Many applications relie on an unbound textbox containing null if the user has not entered data.
In Access , I did post a problem with unbound control default value problem. MSFT Nathan had refered it to them. If you have a unbound control with a default value set, you cannot delete the value when you move to another control.
The default value remain. No, that is incorrect in my testing. For an unbound control without a default, the text box value starts out as null on form load. Just to be clear here. I can certainly say is going to be less often a problem since the nature of un-bound controls tend to no be for data entry. However, as noted, this is a change and this change will bite some people and this kind of change should not occur unless there is some big compelling reason.
So to be clear here, the ONLY change here is when the unbound control has a default setting other than null. This means if code sets control to null, then the control is not going to be null, but as noted here will revert back to the default value — this is a change in behavior for a So your note about a change is correct, but the above statement is wrong.
I wondering if perhaps something is different here due to an input mask or some additional details? Some posts above, I have described my test results in detail. The textbox does NOT start out with value Null if NO default value is set, and code can NOT assign Null to the textbox to be true: it is even worse - code can assign Null to the textbox without any error or warning during compilation or runtime, but after doing so, the textbox has the value "" instead of Null.
Indeed, it is just the other way around: If we SET the default value to Null, then the textbox will start out with this value, and it will be able to be assigned that value and all other values in arbitrary order and keep these values.
Please note that I have conducted the tests using Office x64 on Windows 7 x64, using the English language variants of the software and having applied all latest service packs which are available via Windows Update Windows Update for all Microsoft products.
I don't use any addins or other 3rd-party tools. It might play a role that the application in question is of type adp not accdb ; maybe there are differences between these these two regarding the situation discussed here.
Another reason why you have observed a different behaviour may be that you did use other software versions. If not, it would be very interesting to determine the reason for the difference since what you describe is exactly the behaviour what we want, but what I describe is the behaviour what we get.
Could you please retest with the exact same software configuration as I have described above? Ah ok, you just left out the huge massive large enormous hefty big vast colossal gargantuan mammoth enormous giant great "tiny" little detail you are working with a ADP. Ok, I shall simply move along here, and let others take up the rope here and see how much egg they can have tossed on their face. So I been made a complete fool of, but I can live with this!
I am, simply going to move along on this post and go out of a cup of coffee, a nice strong one! Albert, it wasn't my intention to throw eggs
0コメント