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TppVariable for Subtotal

edited February 2007 in Datapipelines
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  • edited February 2007
    - use the TppVariable.OnCalc event to perform calculations. Do not use
    DetailBand before print. See the Developers Guide Tutorials and the
    Calculations thread of the Tech Tips newsgroups. Here is a quick overview...


    Calculations in ReportBuilder are performed primarily using
    the TppVariable component.

    a. Set the Variable.DataType

    b. Code the calculations using the Variable.OnCalc event.

    c. Use the Timing dialog to control the timing of the OnCalc event.
    To access the Timing dialog, right click over the Variable
    component and select the Timing... option from the speed menu.

    d. Set the LookAhead property to True, when you need to display
    summary calculations in the title, header, group header, etc.

    e. To perform calculations based on the results of other
    calculations use the Calc Order dialog of the band. To access
    the Calc Order dialog, right click over the Band component
    and select the Calc Order... option from the speed menu.


    By using TppVariable components ReportBuilder will take care of caching
    intermediate results of accumlated calcs that cross pages.

    There are a number of calculation examples in the main demos.dpr
    project.

    ---

    Additional Notes:

    1. Do NOT use Band.BeforePrint or Band.AfterPrint. These events fire
    multiple times and therefore should not be used for calculations.

    2. Do NOT store results in variables that exist outside of the reports.
    For example - form level variables.


    --
    Nard Moseley
    Digital Metaphors
    www.digital-metaphors.com

    Best regards,

    Nard Moseley
    Digital Metaphors
    www.digital-metaphors.com
  • edited March 2007
    I have Subtotal which will accumulate detail amount.
    Before the Subtotal is printed, I want to add 3 field value from other other
    dbpipeline.

    Setting:
    Drop Subtotal on ppSummaryBand1, and set DataType to dtCurrency
    I set CalcComponent to ppDetailBand1, and CalcType to veTraversal

    Problem:
    Subtotal was printed correct before I add 3 field value from dbPipeLine.
    But printed wrong Subtotal value after adding 3 field value.
    I put 3 field value calculation on the SummaryBandBeforeGenerate.
    Any steps step are missing ?

    Alternatif way:
    Now, I create dummy variable called vCalcSubtotal and drop it on
    vCalcSubtotal on DetailBand
    Place Subtotal.value := Subtotal.value + detail amount on
    vCalcSubtotal.OnCalc
    Add 3 field value on SummaryBandBeforeGenerate
    Result >>> It print correct Subtotal

    Question:
    Is there any beter way to do this with cleaner coding without Dummy variable
    like vCalcSubtotal above?
  • edited March 2007

    - to create a simple subtotal in the SummaryBand, add a Variable (Variable1)
    to the SummaryBand and implement the Variable.OnCalc to accumulate the
    results.

    Value := Value + myPipeline['AmountPaid'];

    - to add three more fields from another pipeline, add a second Variable
    (Variable2) to the SummaryBand. Use the CalcOrder dialog to set Variable2 to
    calculate after Variable1. Implement the OnCalc event handler

    Value := Variable1.Value + myPipeline['Field1'] + myPipeline['Field2'] +
    myPipeline['Field3'];

    Note: Always use the Timing.. dialog to configure the timing. For most
    calculations, use the default veTraversal for the CalculateOn. And do not
    set the CalcComponent to DetailBand - the dialog will not allow you to do
    this.


    --
    Nard Moseley
    Digital Metaphors
    www.digital-metaphors.com

    Best regards,

    Nard Moseley
    Digital Metaphors
    www.digital-metaphors.com
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