I try to clear error and reset new value in post code filed update

Hi ​@vannakheng,

You're using RaiseExceptionHandling correctly to show the error when a postal code is invalid.

But when the user inputs the correct postal code afterward, you're not clearing the previously raised exception.

Also, SetValueExt may not trigger if the value is the same or if the row state is not correct.

use below code snippet.

protected virtual void _(Events.FieldUpdated<CRAddress.postalCode> e)
{
    if (e.Row == null || e.NewValue == null) return;

    var row = (CRAddress)e.Row;
    string postal = e.NewValue.ToString();

    // Clear previous exception always first
    e.Cache.RaiseExceptionHandling<CRAddressExt.usrDistrict>(row, null, null);

    if (postal.Length == 4)
    {
        string province = postal.Substring(0, 2);
        string district = postal.Substring(0, 4);

        try
        {
            e.Cache.SetValueExt<CRAddress.countryID>(row, "KH");
            e.Cache.SetValueExt<CRAddress.state>(row, province);
            e.Cache.SetValueExt<CRAddressExt.usrDistrict>(row, district);
        }
        catch (PXSetPropertyException ex)
        {
            PXTrace.WriteError($"Error setting values: {ex.Message}");
        }
    }
    else
    {
        // Raise validation error
        e.Cache.RaiseExceptionHandling<CRAddressExt.usrDistrict>(
            row,
            null,
            new PXSetPropertyException("Postal code must be exactly 4 digits.", PXErrorLevel.Error)
        );
    }
}

Hope, it helps!