How To Synchronize Data Displayed on Two Different Forms

MORE INFORMATION

In order to synchronize the data display between two or more independent forms, it is necessary to call the refresh method of the form(s) that contain the data that needs to be refreshed. The methods available for refreshing a form after moving a record pointer are to some extent dependent on how the form is being instantiated.

The following example illustrates use of the Refresh method between two forms:

1. Create a form named TEST1 and change the Caption property to "Employee Form."
2. Add the EMPLOYEE table from the \\SAMPLES\DATA directory to the form's DataEnvironment and set the ORDER to EMP_ID.
3. Drag the following fields from the EMPLOYEE table to the form:

         EMPLOYEE.EMP_ID
         EMPLOYEE.LAST_NAME
         EMPLOYEE.FIRST_NAME
         EMPLOYEE.TITLE

4. Add the following code to the form's Init event:

         DO FORM TEST2

5. Create a form named TEST2 and change the Caption property to "Search Form." Add the EMPLOYEE table from the \\SAMPLES\DATA directory to the form's DataEnvironment and set the ORDER to EMP_ID. In the form's DataEnvironment and set the following values:

         AutoCloseTables=.F.
         AutoOpenTables=.F.

6. Add a list box control that has the following values to the form:

         RowSourceType=6 - Fields
         RowSource=EMPLOYEE.EMP_ID
   							

7. Add the following code to the Click event of the list box control:

         IF !EMPTY(THIS.VALUE)
            IF SEEK(RTRIM(THIS.VALUE))
               * Note that TEST1 is the name of the .SCX file created earlier
               test1.REFRESH
            ENDIF
         ENDIF
   							

8. Save the form.
9. From the command line type "DO FORM TEST1" and use the form captioned "Search Form" to move the record pointer. After you click a value in the list box, the data in the "Employee Form" refreshes.

If the form is being instantiated from a class definition, refreshing the form becomes somewhat more problematic. In this case, the FORMS collection must be used to refresh the target form(s).

The following code illustrates use of the FORMS collection to refresh another form:

1. Create a program file called Demo.prg that contains the following code:

         * Begin Code
         PUBLIC ox
         ox=CREATEOBJECT('SYNCHED1')
         ox.SHOW
   
         DEFINE CLASS synched1 AS FORM
            TOP = 50
            LEFT = 162
            HEIGHT = 160
            WIDTH = 310
            DOCREATE = .T.
            CAPTION = "Employee Form"
            NAME = "Form1"
            AUTOCENTER=.T.
   
            ADD OBJECT lblemp_id AS LABEL WITH ;
               AUTOSIZE = .T., ;
               BACKSTYLE = 0, ;
               CAPTION = "Employee ID", ;
               LEFT = 11, ;
               TOP = 0, ;
               TABINDEX = 3, ;
               NAME = "lblEmp_id"
   
            ADD OBJECT lbllast_name AS LABEL WITH ;
               AUTOSIZE = .T., ;
               BACKSTYLE = 0, ;
               CAPTION = "Last Name", ;
               LEFT = 11, ;
               TOP = 36, ;
               TABINDEX = 5, ;
               NAME = "lblLast_name"
   
            ADD OBJECT lblfirst_name AS LABEL WITH ;
               AUTOSIZE = .T., ;
               BACKSTYLE = 0, ;
               CAPTION = "First Name", ;
               LEFT = 11, ;
               TOP = 72, ;
               TABINDEX = 7, ;
               NAME = "lblFirst_name"
   
            ADD OBJECT lbltitle AS LABEL WITH ;
               AUTOSIZE = .T., ;
               BACKSTYLE = 0, ;
               CAPTION = "Title", ;
               LEFT = 11, ;
               TOP = 108, ;
               TABINDEX = 9, ;
               NAME = "lblTitle"
   
            ADD OBJECT txtemp_id AS TEXTBOX WITH ;
               CONTROLSOURCE = "employee.emp_id", ;
               HEIGHT = 23, ;
               LEFT = 84, ;
               MAXLENGTH = 6, ;
               TABINDEX = 4, ;
               TOP = 0, ;
               WIDTH = 53, ;
               NAME = "txtEmp_id"
   
            ADD OBJECT txtlast_name AS TEXTBOX WITH ;
               CONTROLSOURCE = "employee.last_name", ;
               HEIGHT = 23, ;
               LEFT = 84, ;
               MAXLENGTH = 20, ;
               TABINDEX = 6, ;
               TOP = 36, ;
               WIDTH = 149, ;
               NAME = "txtLast_name"
   
            ADD OBJECT txtfirst_name AS TEXTBOX WITH ;
               CONTROLSOURCE = "employee.first_name", ;
               HEIGHT = 23, ;
               LEFT = 84, ;
               MAXLENGTH = 10, ;
               TABINDEX = 8, ;
               TOP = 72, ;
               WIDTH = 80, ;
               NAME = "txtFirst_name"
   
            ADD OBJECT txttitle AS TEXTBOX WITH ;
               CONTROLSOURCE = "employee.title", ;
               HEIGHT = 23, ;
               LEFT = 84, ;
               MAXLENGTH = 30, ;
               TABINDEX = 10, ;
               TOP = 108, ;
               WIDTH = 218, ;
               NAME = "txtTitle"
   
            PROCEDURE LOAD
               PUBLIC varval
               IF ATC("Visual FoxPro 06.",VERSION())>0
               USE Home(2)+"Employee.dbf"
               Else
               USE home()+"\samples\data\employee"
               ENDIF
               SET ORDER TO TAG emp_id
               GO TOP
               STORE SPACE(LEN(employee.emp_id)) TO m.varval
            ENDPROC
   
            PROCEDURE DESTROY
               FOR i=1 TO _SCREEN.FORMCOUNT
                  * Look for the Search Form in the FORMS collection.
                  IF _SCREEN.FORMS(i).CAPTION="Search Form"
                     * If the Search Form exists, release it
                     _SCREEN.FORMS(i).RELEASE
                  ENDIF
               ENDFOR
               * Close the table.
               SELECT employee
               USE
            ENDPROC
   
            PROCEDURE INIT
               * Launch the Search Form.
               PUBLIC search
               search=CREATEOBJECT('SYNCHED2')
               search.SHOW
            ENDPROC
         ENDDEFINE
   
         DEFINE CLASS synched2 AS FORM
            TOP = 0
            LEFT = 0
            HEIGHT = 118
            WIDTH = 205
            DOCREATE = .T.
            CAPTION = "Search Form"
            NAME = "Form2"
   
            ADD OBJECT list1 AS LISTBOX WITH ;
               ROWSOURCETYPE = 0, ;
               HEIGHT = 96, ;
               LEFT = 24, ;
               TOP = 12, ;
               WIDTH = 145, ;
               NAME = "List1"
   
            PROCEDURE INIT
               THIS.list1.ROWSOURCETYPE=1
               IF USED('EMPLOYEE')
                  SELECT employee
                  currec=RECNO()
                  GO TOP
                  SCAN
                     * Load the list box with data from the table.
                     THIS.list1.ADDLISTITEM(employee.emp_id)
                  ENDSCAN
                  GOTO currec
               ENDIF
            ENDPROC
   
            PROCEDURE list1.CLICK
               IF !EMPTY(THIS.VALUE)
                  SELECT employee
                  IF SEEK(RTRIM(THIS.VALUE))
                     * Move the record pointer
                     FOR i=1 TO _SCREEN.FORMCOUNT
                        * Look for the Employee Form in the FORMS collection.
                        IF _SCREEN.FORMS(i).CAPTION="Employee Form"
                           * If the Employee Form exists, Refresh it
                           _SCREEN.FORMS(i).REFRESH
                        ENDIF
                     ENDFOR
                  ENDIF
               ENDIF
            ENDPROC
   
            PROCEDURE DESTROY
               FOR i=1 TO _SCREEN.FORMCOUNT
                  * Look for the Employee Form in the FORMS collection.
                  IF _SCREEN.FORMS(i).CAPTION="Employee Form"
                     * If the Employee Form exists, release it
                     _SCREEN.FORMS(i).RELEASE
                  ENDIF
               ENDFOR
            ENDPROC
         ENDDEFINE
         * End Code.
   							

2. From the command line type "DO DEMO" and use the form captioned "Search Form" to move the record pointer. After clicking a value in the list box, the data in the Employee Form refreshes.