When you set data in a DataWindow control, the datatypes of the source values must match the datatypes of the columns being set.
When your data expression refers to a single row and column, you can set the value in the DataWindow control with a value that matches the column’s datatype. When you are setting values in a single column and specifying an expression that can refer to multiple rows, the values you assign must be in an array of the appropriate datatype.
When the expression refers to more than one column, you can assign the data with a structure or user object to the DataWindow data. When you create the definition, the fields (in a structure) or instance variables (in a user object) must match the columns. There must be the same number of fields or variables, defined in the same order as the columns, with compatible datatypes.
When your expression can refer to multiple rows, you need an array of the structure or user object.
You do not have to know in advance how many rows are involved when you are setting data in the DataWindow control. PowerBuilder uses the number of elements in the source array and the number of rows in the target expression to determine how to make the assignment and whether it is necessary to insert rows.
If the target expression is selected rows or a range of rows, then:
When there are more array elements than target rows, the extra array elements are ignored
When there are fewer array elements than target rows, the column(s) in the extra target rows are filled with default values
If the target expression is all rows but not all columns, then:
When there are more array elements than target rows, the extra array elements are ignored
When there are fewer array elements than target rows, only the first rows up to the number of array elements are affected
If the target expression is all rows and all columns, then the source data replaces all the existing rows, resetting the DataWindow control to the new data.
Inserting new rows When you are setting data and you specify a range, then if rows do not exist in that range, rows are inserted to fill the range. For example, if the DataWindow control has four rows and your expression says to assign data to rows 8 through 12, then eight more rows are added to the DataWindow control. The new rows use the initial default values set up for each column. After the rows are inserted, the array of source data is applied to the rows as described above.
These examples refer to a DataWindow object that has three columns: emp_id, emp_lname, and salary. The window declares these arrays as instance variables and the window’s Open event assigns four elements to each array:
integer ii_id[]
string is_name[]
double id_salary[]
uo_empdata iuo_data[]
uo_empid_name iuo_id[]
The uo_empdata user object has three instance variables: id, name, and salary. The uo_empid_name user object has two instance variables: id and name.
This example sets emp_lname in the selected rows to the values of is_name, an array with four elements. If two rows are selected, only the first two values of the array are used. If six rows are selected, the last two rows of the selection are set to an empty string:
dw_1.Object.emp_lname.Selected = is_name
This example sets salary in rows 8 to 12 to the values in the array id_salary. The id_salary array has only four elements, so the extra row in the range is set to 0 or a default value:
dw_1.Object.salary[8,12] = id_salary
This statement resets the DataWindow control and inserts four rows to match the array elements of iuo_data:
dw_1.Object.Data.Primary = iuo_data
This example sets columns 1 and 2 in rows 5 to 8 to the values in the array iuo_id:
dw_1.Object.Data.Primary[5,1, 8,2] = iuo_id
This example sets emp_id in the first four rows to the values in the ii_id array. Rows 5 through 12 are not affected:
dw_1.Object.emp_id.Primary = ii_id
