Reports the next row and column that is required and contains a null value. The method arguments that specify where to start searching also store the results of the search. You can speed up the search by specifying that FindRequired check only inserted and modified rows.
DataWindow type |
Method applies to |
|---|---|
PowerBuilder |
DataWindow control, DataStore object |
Web ActiveX |
DataWindow control |
integer dwcontrol.FindRequired ( DWBuffer dwbuffer, long row, integer colnbr, string colname, boolean updateonly )
number dwcontrol.FindRequired ( number dwbuffer, number row, number colnbr, string colname, boolean updateonly )
Returns 1 if FindRequired successfully checked the rows and –1 if an error occurs.
If any argument’s value is null, in PowerBuilder and JavaScript the method returns null.
For FindRequired to report an empty required column, the column’s value must actually be null, not an empty string.
To make a column required, set the Required property to true in a script or check the Required check box for the column in the DataWindow painter.
New rows have null values in their columns, unless the columns have default values. If updateonly is false, FindRequired reports empty required columns in new rows. If updateonly is true, FindRequired does not check new rows because new, empty rows are not updated in the database.
When the user modifies a row and leaves a column empty, the new value is an empty string, unless the column’s edit style has the Empty String Is null check box checked. FindRequired does not report empty required columns in modified rows unless this property is set.
The following code makes a list of all the row numbers and column names in dw_1 in which required columns are missing values. The list is displayed in the MultiLineEdit mle_required:
long ll_row = 1
integer colnbr = 0
string colname
mle_required.Text = ""
DO WHILE ll_row <> 0
colnbr++ // Continue searching at next column
// If there's an error, exit
IF dw_1.FindRequired(Primary!, &
ll_row, colnbr, &
colname, false) < 0 THEN EXIT
// If a row was found, save the row and column
IF ll_row <> 0 THEN
mle_required.Text = mle_required.Text &
+ String(ll_row) + "~t" &
+ colname + "~r~n"
END IF
// When FindRequired returns 0 (meaning
// no more rows found), drop out of loop
LOOP
This example is a function that ensures that no required column in a DataWindow control is empty (contains null). It takes one argument—the DataWindow control, which is declared in the function declaration like this:
DataWindow adw_control
The function returns –2 if the user’s last entry cannot be accepted or if FindRequired returns an error. It returns –1 if an empty required column is found. It returns 1 if all required columns have data:
integer li_colnbr = 1
long ll_row = 1
string ls_colname, ls_textname
// Make sure the last entry is accepted
IF adw_control.AcceptText() = -1 THEN
adw_control.SetFocus()
RETURN -2
END IF
// Find the first empty row and column, if any
IF adw_control.FindRequired(Primary!, ll_row, &
li_colnbr, ls_colname, true) < 1 THEN
//If search fails due to error, then return
RETURN -2
END IF
// Was any row found?
IF ll_row <> 0 THEN
// Get the text of that column's label.
ls_textname = ls_colname + "_t.Text"
ls_colname = adw_control.Describe(ls_textname)
// Tell the user which column to fill in
MessageBox("Required Value Missing", &
"Please enter a value for '" &
+ ls_colname + "', row " &
+ String(ll_row) + ".", &
StopSign! )
// Make the problem column current.
adw_control.SetColumn(li_colnbr)
adw_control.ScrollToRow(ll_row)
adw_control.SetFocus()
RETURN -1
END IF
// Return success code if all required
// rows and columns have data
RETURN 1
