Using the Windows clipboard
It is very easy to read and write data on the Windows clipboard from
Visual FoxPro and this is often the easiest way to transfer data between
applications. The clipboard is not as sophisticated as using Automation
or DDE but it's quick and simple and popular with users because it is a
flexible technique which leaves them in control of the process.
The two commands are
_CLIPTEXT
to copy text to the clipboard and
DataToClip()
to copy values from a table.
_CLIPTEXT
Use the _CLIPTEXT system variable to read and
write text to the clipboard. For example a button on a Customer form can
assemble the four lines of the address into a block of text on the
clipboard:
Declare laLines[4]
laLines = ""
lnLine = 1
If Not Empty(Address1)
laLines[lnLine] = Alltrim(Address1)
lnLine = lnLine + 1
EndIf
If Not Empty(Address2)
laLines[lnLine] = Alltrim(Address2)
lnLine = lnLine + 1
EndIf
If Not Empty(Town)
laLines[lnLine] = Alltrim(Town)
lnLine = lnLine + 1
EndIf
If Not Empty(County)
laLines[lnLine] = Alltrim(County)
lnLine = lnLine + 1
EndIf
_CLIPTEXT
= laLines[1] +
Chr
(13) + ;
laLines[2] + Chr(13) + ;
laLines[3] + Chr(13) + ;
laLines[4]
With the address on the clipboard the user can switch to Microsoft Word
and paste the block as the header of a letter or go to Excel and paste
the address into an invoice.
This example used CHR(13) to insert a carriage return between each field
so that the address will paste as four lines in Word or Excel. If you use
CHR(9) to insert tab characters then the address will paste as four cells
on the same line in a Word table or in Excel.
DataToClip()
DataToClip
is a method of the application object and of the
_VFP
system variable. It copies data from the current work area onto the
clipboard. If the TasTrade Customer table is open then the command:
_vfp.DataToClip()
will copy all the records of the current table onto the clipboard. The image
below shows the effect of
_vfp.DataToClip()
followed by CTRL+V to paste the clipboard contents back into the Command
Window:
![[Table contents in the Command Window]](../media/images/datatoclip.gif "Text pasted from the clipboard to the Command Window")
There's not enough space here to show the entire output but every field of
every row of the table has been placed on the Clipboard. Fields are
separated by a single space and each record is on a new line.
The Cust_ID field is six characters wide. Each ID is only five characters
long so there is a trailing space in the field followed by the space which
separates fields.
Note that this screen shot is from Visual FoxPro 9 with the
View White Space option selected to make the spaces visible.
Parameters
DataToClip()
accepts up to three parameters:
- cAlias: The work area from which records are copied
- nRecords: Copy a specific number of records
- nFormat: 1=Delimit with spaces, 3=Delimit with tabs
Notes
There are some annoying limitations to
DataToClip():
- The first line of the output will always be the field names.
- There is no way of selecting which fields will be copied.
-
Memo fields are represented as 'Memo' or 'memo' depending on
whether they hold any text.
- General fields are not copied.
The best way to use DataToClip() is in
conjunction with an SQL statement which will select the fields and records
required into a cursor.
Finally, note that
DataToClip()
does not behave like a traditional FoxPro data export command. It cannot
accept a FOR clause and the act of copying to the clipboard does not move
the record pointer.
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