OpenArgs - add 2nd criteria

OpenArgs is a string, and you can pass whatever you want, but:
You'll need to take care of parsing the string.
You'll need to take special care of Null values because VBA implicitly convert Null values to empty strings, and this is not the same thing.

OK.

You are using your OpenArgs to build a filter

A filter is the WHERE clause of a query without the word 'where' stuck in front of it

Your error says [BuyCP] = Chevron

Chevron being a string means you clearly have some syntax misbehaving as what it need to be is

[BuyCP] = "Chevron"

Then you have the problem of those extra couple of semi-colons

[BuyCP] = Chevron;;

as they were delimiters in your string and should have gone away

Finally you have AND [Trade_No] = and then nothing, so you have some null/blank/error handling issues

So let's take your Open command 

Private Sub btnIssueLC2_Click()

      DoCmd.OpenForm "frmLetterOfCredit", acFormDS, , , , , Form_subfrmProjects_Extended_List.Buy_CP & ";" & Me.Trade_No & ";"
    
End Sub

and fix it to handle both issues.

Some guys like lots and lots of "'""""""" when handling strings.

Me,  not so much since it makes code hard to read (i.e. how many single and double-quotes are in my little string there?)

Chr(34) is a double quote.  We're going to wrap Form_subfrmProjects_Extended_List.Buy_CP in double quotes

Chr(34) & Form_subfrmProjects_Extended_List.Buy_CP & Chr(34)

That will result in [BuyCP] = "Chevron" in the filter, just like we want

Then we have Me.Trade_No.

What happens when that is blank or null?

From your sample the other day, I can see it is a string, so we need to wrap it in double-quotes, too

Chr(34) & Me.Trade_No & Chr(34)

Now we have a slight third problem

You built a semi-colon delimited string -- but you ONLY need semi-colons between items and you have tacked on a trailing one.  I think that causes problems.  So, we get

Private Sub btnIssueLC2_Click()

      DoCmd.OpenForm "frmLetterOfCredit", acFormDS, , , , , chr(34) & Form_subfrmProjects_Extended_List.Buy_CP & Chr(34) & ";" & Chr(34) Me.Trade_No & Chr(34)
   
End Sub

That's one way BUT you still have nulls and blanks to handle--so let's do this instead

Private Sub btnIssueLC2_Click()

      DoCmd.OpenForm "frmLetterOfCredit", acFormDS, , , , , Nz(Form_subfrmProjects_Extended_List.Buy_CP,"") & ";"  Nz(Me.Trade_No,"")
   
End Sub

That'll clean up the nulls and blanks.

Now to build your filter

Private Sub Form_Load()
Dim ArgsSplit() as String 'array to hold the string we've sent in
 If Nz(Me.OpenArgs, "") = "" Then 
    exit sub 'no arguments were sent in so bail
End if


'if we got here we have an argument to work with
'be nice to yourself and just split it -- then you can for...next the array if things get wild to see what is happening
ArgsSplit() = Split(Me.OpenArgs, ";") 'two values, positions 0 and 1 holding strings you want to use


'Now deal with the possibilities
if ArgsSplit(0) <> "" then 'there was a first argument      
            Me.Filter = "[Buy_CP] = " & Chr(34) &  ArgsSplit(0) & "  & Chr(34)
end if
'Now, was there a first AND second argument?
if ArgsSplit(0) <> "" AND if ArgsSplit(1) <> "" then 'two arguments
    Me.Filter = Me.Filter & " AND [Trade_No] = " & Chr(34) & ArgsSplit(1) & Chr(34) 'add on the second WHERE condition
End if


'Ok if there was no first argument, we have nothing in the filter yet, so
if ArgsSplit(0) = "" AND if ArgsSplit(1) <> "" then 'only second arguments
    Me.Filter = "[Trade_No] = " & Chr(34) & ArgsSplit(1) & Chr(34) 'Just add the second WHERE condition
End if


'there.  Two possibilities renders 4 cases and they are handled.
'1 Bail on no arguments
'2 Check for the first and add it if it exists
'3 check for the second and tack it on if it exists
'4 check for only a second and build it only

'if we got here, turn on the filter
Me.FilterOn = True


'and done
End Sub 

Oops.

Some sloppiness in copy/paste

I got a few misplaced 'ifs' in the code

Private Sub Form_Load() 
Dim ArgsSplit() as String 'array to hold the string we've sent in
If Nz(Me.OpenArgs, "") = "" Then
     exit sub 'no arguments were sent in so bail
End if 
'if we got here we have an argument to work with
'be nice to yourself and just split it -- then you can for...next the array if things get wild to see what is happening
ArgsSplit() = Split(Me.OpenArgs, ";") 'two values, positions 0 and 1 holding strings you want to use 
'Now deal with the possibilities
if ArgsSplit(0) <> "" then 'there was a first argument              
    Me.Filter = "[Buy_CP] = " & Chr(34) &  ArgsSplit(0) & "  & Chr(34)
end if 
'Now, was there a first AND second argument?
if ArgsSplit(0) <> "" AND ArgsSplit(1) <> "" then 'two arguments
     Me.Filter = Me.Filter & " AND [Trade_No] = " & Chr(34) & ArgsSplit(1) & Chr(34) 'add on the second WHERE condition
End if 
'Ok if there was no first argument, we have nothing in the filter yet, so
if ArgsSplit(0) = "" AND ArgsSplit(1) <> "" then 'only second arguments
     Me.Filter = "[Trade_No] = " & Chr(34) & ArgsSplit(1) & Chr(34) 'Just add the second WHERE condition
End if
 'there.  Two possibilities renders 4 cases and they are handled.
'1 Bail on no arguments
'2 Check for the first and add it if it exists
'3 check for the second and tack it on if it exists
'4 check for only a second and build it only 
'if we got here, turn on the filter
Me.FilterOn = True 
'and done 
End Sub

There's a typo in the code

Me.Filter = "[Buy_CP] = " & Chr(34) &  ArgsSplit(0) & "  & Chr(34)"

should be

Me.Filter = "[Buy_CP] = " & Chr(34) &  ArgsSplit(0) & Chr(34)

Good catch.

Again, my bad.

Air code rather than written in the IDE and compiled to catch boo-boos.

Thanks

Nick67

You are missing  an & after the semicolon too

It is always hard to debug monolithic code.

So BEFORE your DoCmd code put

Dim MyArgs as string

MyArgs =Nz(Form_subfrmProjects_Extended_List.Buy_CP,"")

MyArgs = MyArgs & “;”

MyArgs = MyArgs & Nz(Me.Trade_No,"")

Then replace the big mess in the DoCmd with MyArgs.

You can msgbox MyArgs and breakpoint it to ensure it builds correctly.

Fine tune!

Yes, the semicolon should be there

It’s your string delimiter.

But there is no value after it, and that is your where your trade_no value should be.

So, what is fouled up that myArgs didn’t get a value for trade_no?

Msgbox   Nz(Me.Trade_No, “no value dummy!”)

And see what you get.

Your CP value came from some other form, not Me

Where is Trade_No actually coming from?

I always insult myself with my debugging code.

Keeps me humble and makes me smile.

The f-bomb in code comments reminds me that something was particularly tough.

When I get something to work I make notes in the code about the thought process 

If it is not on Me then that is DEFINITELY an logic issue.

Sort that first and then sort the syntax issues of getting the right number of quotes in the right places

The myargs should be 

Myargs =

Myargs = myargs & 

Myargs = myargs &

We’re cumulatively adding to the string

My bad

You and I have been at this a long time.  I just took a five year break.

You’re welcome