<Table>.FormulaAdd (Function)

ONLINE HELP
WINDEV, WEBDEV AND WINDEV MOBILE

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 to a Table or TreeView Table control by providing custom calculation procedures.

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

Index of the row containing the formula.

<Column>: Control name

Name of column into which the formula will be added.

<Calculation caption>: Character string

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

Name of the WLanguage procedure ("callback") 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 return value for the first iteration of the calculation.
NULL if the formula requires no initialization process.

<Iteration>: Character string

Name of the WLanguage procedure ("callback") called for each iteration of the formula (each row of the Table control). This procedure has read-only access to the columns of each row. This procedure has the following format:

PROCEDURE <Procedure name>(<Accumulator>, <Column value>)
// Called for each row in the Table control
// 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 iteration process.

<Ending>: Character string

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

PROCEDURE <Procedure name> (<Accumulator>)
// your code

RESULT <End value Accumulator>

where:
<Accumulator> is the value coming from the previous calculation (initialization or previous iteration).
<End value Accumulator> is the return value that corresponds to the end value of the 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 control, a new calculation row is added below the Table control (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 of a Table or TreeView Table control based on a data file.
on the columns of a Table or TreeView Table control populated programmatically.

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. For more details, see Programming custom calculations in Table controls.

Component: wd270obj.dll