Why are values resetting to zero and null when press save?

Hi ​@RKarunarathne51 ,
Write code on RowPersisting event assign value their value will get save on database.

Here are the key changes and explanations to fix your issue:

1. Add PXDefault attributes:
   • For required fields, add the [PXDefault] attribute
   • For optional fields, use [PXDefault] with PersistingCheck = PXPersistingCheck.Nothing
   • For numeric fields, provide a default value
     Example:

     #region LotSerialNbr
     [PXDBString(100, IsUnicode = true, InputMask = "")]
     [PXDefault(PersistingCheck = PXPersistingCheck.Nothing)] // Allows null values but ensures field binds properly
     [PXUIField(DisplayName = "Lot Serial Nbr")]
     public virtual string LotSerialNbr { get; set; }
     public abstract class lotSerialNbr : PX.Data.BQL.BqlString.Field<lotSerialNbr> { }
     #endregion

     #region Quantity
     [PXDBDecimal()]
     [PXDefault(TypeCode.Decimal, "0.0", PersistingCheck = PXPersistingCheck.Nothing)] // Defaults to 0.0 for numeric fields
     [PXUIField(DisplayName = "Quantity")]
     public virtual Decimal? Quantity { get; set; }
     public abstract class quantity : PX.Data.BQL.BqlDecimal.Field<quantity> { }
     #endregion
      

2. Value persistence strategies:
   • Override the Persist method in your graph to ensure values are properly set
   • Add a RowPersisting event handler to validate values before saving
   • Use Cache.GetValueExt to retrieve the actual values from the UI

Example:
In your graph, explicitly set values in the cache during redirection or initialization:

protected void _(Events.RowInserted<MyCustomDAC> e)
{
    var row = e.Row;
    if (row == null) return;

    // Ensure LotSerialNbr and Quantity are initialized
    if (string.IsNullOrEmpty(row.LotSerialNbr))
        row.LotSerialNbr = "DEFAULT_SERIAL";
    if (row.Quantity == null)
        row.Quantity = 1.0m; // Default quantity
}

Use RowPersisting to ensure values are not cleared during save:
 

protected void _(Events.RowPersisting<MyCustomDAC> e)
{
    var row = e.Row;
    if (row == null) return;

    // Debugging
    PXTrace.WriteInformation($"LotSerialNbr: {row.LotSerialNbr}, Quantity: {row.Quantity}");

    // Ensure these fields are valid before persisting
    if (string.IsNullOrEmpty(row.LotSerialNbr))
        throw new PXRowPersistingException(nameof(row.LotSerialNbr), null, "Lot Serial Nbr cannot be empty.");
}
 

Hope it will work.