sum records of a grid and show the total in a header value

Question

how to calculate the sum of all volumes and display the total in the Total volume field as shown below.

Answer 1

First we will create on INRegister DAC a Usr decimal field that will hold the value of "Total Volume".

Please note that any DAC extension fields that utilize [PXDefault] attribute should have the Persisting check set to PXPersistingCheck.Nothing this will prevent errors occuring when trying to save legacy documents within the system.

public class INRegisterExtension : PXCacheExtension<INRegister>
    {
        #region UsrTotalVolume
        public abstract class usrTotalVolume : BqlDecimal.Field<usrTotalVolume>
        {
        }
        [PXDBDecimal]
        [PXDefault(TypeCode.Decimal, "0.00", PersistingCheck = PXPersistingCheck.Nothing)]
        [PXUIField(DisplayName = "Total Volume")]
        public virtual decimal? UsrTotalVolume { get;set;}
        #endregion
    }

Next we will create our detail level Usr field which will hold the value of "Volume" within the grid.

public class INTranExtension : PXCacheExtension<INTran>
{
    #region UsrVolume
    public abstract class usrVolume : BqlDecimal.Field<usrVolume>
    {
    }
    [PXDBDecimal]
    [PXDefault(TypeCode.Decimal, "0.00", PersistingCheck = PXPersistingCheck.Nothing)]
    [PXUIField(DisplayName = "Volume")]
    public virtual decimal? UsrVolume { get; set; }
    #endregion
}

Finally we will create a PXGraphExtension which will append the [PXFormula] attribute to our child Usr field allowing the calculations you desire specifically in the context of this data entry screen.

If a formula is included on a DAC it's logic is called whenever the DAC is utilized ( GI, Reports, Ect ) thus we add it on a Graph Extension so we are only utilizing logic when needed, i.e. on the data entry page.

public class INTransferEntryExtension : PXGraphExtension<INTransferEntry>
{
    [PXMergeAttributes(Method = MergeMethod.Append)]
    [PXFormula(null, typeof(SumCalc<INRegisterExtension.usrTotalVolume>))]
    protected virtual void __(Events.CacheAttached<INTranExtension.usrVolume> e)
    {
    }
}

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