Unexpected behaviour when assign value to "Default Value" property

[ADIGA88]

hi guys

I have weird behavior when i am tring to assign value from textbox to another textbox default value, the example will make it clear.
Environment:
windows 10
office 365
access VBA

' this is not working
Me.Txt_Vendor_Name.DefaultValue = """ & Me.Txt_DefaultVendorName & """

' this is working just fine
Me.Txt_Vendor_Name.DefaultValue = "'" & Me.Txt_DefaultVendorName & "'"

the not working example just use Me.Txt_DefaultVendorName as text and put it as it's.
knowing multiple threads suggest the not working example.

 

[CJ_London]

all you need is

Me.Txt_Vendor_Name.DefaultValue = Me.Txt_DefaultVendorName

note that default value will only populate for new records - if the record already exists, although the defaultvalue property will be populated, it will not appear in an existing record.

 

[pbaldy]

Looks like it needs to be 4 double quotes, not 3:

Forms: Carry current value of a control to new records

 

[ADIGA88]

all you need is

Me.Txt_Vendor_Name.DefaultValue = Me.Txt_DefaultVendorName

note that default value will only populate for new records - if the record already exists, although the defaultvalue property will be populated, it will not appear in an existing record.

In this case both date and text textboxs is not working

You don't have enough double quotes:

Me.Txt_Vendor_Name.DefaultValue = """" & Me.Txt_DefaultVendorName & """"

You need four in this case. The outer two enclose the literal. Since the literal is a delimiter it needs to be "escaped" and so it must be entered twice.

In order to not have to deal with reading bunches of quotes, I create a global constant named QUOTE:

Option Compare Database
Option Explicit

Public Const QUOTE = """"

I keep a standard module where I define all public variables and TempVars so they are all located in one place. Using the constant, the expression would be:
Me.Txt_Vendor_Name.DefaultValue = QUOTE & Me.Txt_DefaultVendorName & QUOTE

If Not IsNull(Me.Txt_DefaultDate) Then Me.Txt_Attendance_Date.DefaultValue = "'" & Me.Txt_DefaultDate & "'"
If Not IsNull(Me.Txt_DefaultVendorName) Then Me.Txt_Vendor_Name.DefaultValue = """" & Me.Txt_DefaultVendorName & """"

the four quote make sense for the need of escaping the literal, but why the second case is working " ' " & variable & " ' "
I will go with 4 quotes for now as the second case maybe failed in some exception.