Instead, you need to create code that checks the value of the text box and changes the background color accordingly.
Let's take a look at an example.
In this example, we have a form called Suppliers. We want to change the background color of the ContactTitle text box if the user has not filled in a value. (ie: If the text box contains a null value).
First, you want to view the properties for the Form. Select the property called "On Current". A button with three dots should appear to the right. Click on the button.
When the Choose Builder window appears, highlight "Code Builder" and click on the OK button.
Next, we want to enter the following code:
If IsNull(ContactTitle) = True Then
ContactTitle.BackColor = vbRed
Else
ContactTitle.BackColor = vbWhite
End If
The purpose of this code is to change the background color of the ContactTitle field to red if it is null, or white if it has a value. We place this code on the Form's On Current event so that when you scroll through the records in the Supplier form, the ContactTitle field will reformat itself.
You can close down the Microsoft Visual Basic window.
Next, you need to place similar code on the text box's After Update event.
To do this, select the properties for the ContactTitle text box. Click on the property called "After Update". A button with three dots should appear to the right. Click on the button.
When the Choose Builder window appears, highlight "Code Builder" and click on the OK button.
Now, we want to enter the same code on this event:
If IsNull(ContactTitle) = True Then
ContactTitle.BackColor = vbRed
Else
ContactTitle.BackColor = vbWhite
End If
We place this code on the text box's After Update event so that once a user enters a value in the ContactTitle field, the text box will reformat itself again.
When we take a look at our form, we see that if the ContactTitle field is blank/null, the background color is red.
Once a user enters a value, the background color will change back to white.
