<Table>.FormulaAdd (Function)

WINDEV, WEBDEV AND WINDEV MOBILE
ONLINE HELP

Version:

Home | Sign in | English

Help

WLanguage

WLanguage functions

Controls, pages and windows

Conditions for adding the row containing the custom calculation formula

Recalculating data

Customizing the calculation row

See also

<Table>.FormulaAdd (Function)

In french: <Table>.FormuleAjoute

Adds a calculated row into a Table control by providing the procedures for custom calculations.

Example

TABLE_MyTable.FormulaDeleteAll()
nRow is int
nRow = TABLE_MyTable.COL_Num.FormulaAdd("Positive mean", ProcInit, ProcAdd, ProcEnd)
// Change the background color of the row for custom calculation
COL_Num[nRow]..BackgroundColor = LightRed

nCounter is int
INTERNAL PROCEDURE ProcInit()
nCounter = 0
RESULT 0
END

INTERNAL PROCEDURE ProcAdd(Accumulator, ColValue)
// Ignores the negative numbers or NULL
IF (ColValue <= 0) RESULT Accumulator
nCounter++
RESULT Accumulator + ColValue
END
INTERNAL PROCEDURE ProcEnd(Accumulator)
IF nCounter = 0 THEN RESULT 0
// Calculate the mean
RESULT Accumulator/nCounter
END

nRow2 is int
nRow2 = TABLE_TableControl.COL_Time.FormulaAdd("Average duration", Null, ...
AverageDuration_Iteration, AverageDuration_End)

INTERNAL PROCEDURE AverageDuration_Iteration(Accumulator, ColValue)
RESULT Accumulator + [TAB] + ColValue
END

INTERNAL PROCEDURE AverageDuration_End(Accumulator)
nSum is 8-byte int
nNbValid is int
FOR EACH STRING sValue OF Accumulator SEPARATED BY TAB
IF ValidTime(sValue) THEN
nSum += TimeToInteger(sValue)
nNbValid++
END
END
RESULT TimeToString(IntegerToTime(nSum/nNbValid), "HH:MM:SS")
END

Syntax

<Result> = <Column>.FormulaAdd(<Calculation caption> , <Initialization> , <Iteration> , <Ending>)

<Result>: Integer

Subscript of the row containing the formula.

<Column>: Control name

Name of column into which the formula will be added.

<Calculation caption>: Character string (with quotes)

Caption of the additional row where the calculation will be displayed.
If this caption does not exist, the row will be created.
If this caption exists but not for the specified column, the calculation is displayed in the existing row but for the specified column.
If this caption exists for the specified column, a WLanguage error occurs.

<Initialization>: Character string (with or without quotes)

Name of WLanguage procedure ("callback" procedure) that will be called to initialize the formula. This procedure has the following format:

PROCEDURE <Procedure name> ()
// your code

RESULT <Initialization value Accumulator>

where <Initialization value Accumulator> is the value to return for the first iteration of the calculation.
NULL if the formula requires no initialization process.

<Iteration>: Character string (with or without quotes)

Name of WLanguage procedure ("callback" procedure) that will be called for each iteration of the formula (each table row). This procedure has the following format:

PROCEDURE <Procedure name>(<Accumulator>, <Column value>)
// Called for each table row
// Your code

RESULT <New value Accumulator>

where:
<Accumulator> is the value coming from the previous calculation (initialization or previous iteration).
<Column value> is the value of the current column used to calculate this iteration.
<New value Accumulator> is the new value to return for the next iteration or at the end of calculation.
NULL if the formula requires no initialization process.

<Ending>: Character string (with or without quotes)

Name of the WLanguage procedure ("callback" procedure) that will be called to end the formula. This procedure has the following format:

PROCEDURE <Procedure name> ()
// your code

RESULT <End value Accumulator>

where <End value Accumulator> is the value to return corresponding to the value of end of calculation.
NULL if the formula requires no ending process.

Remarks

Conditions for adding the row containing the custom calculation formula

If the calculation named <Calculation caption> does not exist in the table, a new calculation row is added below the table (after the existing calculations).
If a calculation named <Calculation caption> was already defined for another column, the calculation is displayed for the specified column in the existing calculation row.
If a calculation named <Calculation caption> was already defined for the same column, a WLanguage error occurs.
Only 5 custom calculation rows can be added.

Remark: This function can be used:

on the columns found in a Table or TreeView Table control.
on the columns found in the memory or browsing controls.

Recalculating data

The custom calculation rows are automatically recalculated as soon as the content of the Table control changes.

Tip: The iteration procedure is called for each row: we advise you not to perform slow calculations (avoid the accesses to the database for example).

Customizing the calculation row

The following syntax is used to customize the added row (caption, color, font, height, ...):

<Table control>[Row number]..<Property> = <New value>

where <Property> can correspond to one of the properties that can be used on a column of a Table control. See Programming custom calculations in Table controls for more details.

Component : wd250obj.dll