Have a Process Screen, Its data source is a projection view that displays fine but when I click on select, the row blanks out

You’re using @P.AsDateTime in your projection query. I’m guessing that’s the issue.

Why is that an issue? I have used it before with projection views doing the same exact thing? 

Thats getting set in the constructor for the projection view: 

View.ReadOnly.Select(this,
                    new object[] { DateTime.Today, DateTime.Today })
                .Cast<PXResult<Customer, Location, InventoryItem, INSiteStatus, ARSalesPrice>>())

Sorry cut it off see bold italic: 

foreach (PXResult<Customer, Location, InventoryItem, INSiteStatus, ARSalesPrice> results in
    SelectFrom<Customer>
    .InnerJoin<Location>.On<Customer.bAccountID.IsEqual<Location.bAccountID>
    >
    .CrossJoin<InventoryItem>
    .InnerJoin<INSiteStatus>.On<InventoryItem.inventoryID.IsEqual<INSiteStatus.inventoryID>>
    .InnerJoin<ARSalesPrice>.On<Customer.bAccountID.IsEqual<ARSalesPrice.customerID>
    .And<InventoryItem.inventoryID.IsEqual<ARSalesPrice.inventoryID>>
    .And<ARSalesPrice.priceType.IsEqual<PriceTypeList.customer>>
    >
    .Where<Customer.status.IsEqual<CustomerStatus.active>.And<InventoryItem.itemStatus.IsEqual<InventoryItemStatus.active>
        .And<InventoryItem.stkItem.IsEqual<True>>
        .And<InventoryItem.isTemplate.IsEqual<False>>
        .And<ARSalesPriceExt.usrSrItemClassID.IsNull>
        .And<ARSalesPrice.breakQty.IsEqual<decimal0>>
        .And<ARSalesPrice.salesPrice.IsGreater<decimal0>>
        .And<ARSalesPrice.effectiveDate.IsLessEqual<@P.AsDateTime>>
        .And<ARSalesPrice.expirationDate.IsGreater<@P.AsDateTime>>
        >>
    .AggregateTo<GroupBy<Customer.bAccountID>, GroupBy<Location.locationID>, GroupBy<InventoryItem.inventoryID>,
    GroupBy<Location.locationCD>, GroupBy<Customer.acctCD>, GroupBy<InventoryItem.inventoryCD>, GroupBy<InventoryItem.descr>, GroupBy< InventoryItem.salesUnit>
    >
    
    .View.ReadOnly.Select(this,
        new object[] { DateTime.Today, DateTime.Today })
    .Cast<PXResult<Customer, Location, InventoryItem, INSiteStatus, ARSalesPrice>>())

Hmm. Perhaps I’m naive. I’ve never seen that before. I understood a projection to be a rather delicate mashup of several tables.

So you defined a projection. Could you post the whole projection class, fields, and all?

[Serializable]
[PXHidden]
[PXProjection(typeof(SelectFrom<Customer>
            .InnerJoin<Location>.On<Customer.bAccountID.IsEqual<Location.bAccountID>
            >
            .CrossJoin<InventoryItem>
            .InnerJoin<INSiteStatus>.On<InventoryItem.inventoryID.IsEqual<INSiteStatus.inventoryID>>
            .InnerJoin<ARSalesPrice>.On<Customer.bAccountID.IsEqual<ARSalesPrice.customerID>
            .And<InventoryItem.inventoryID.IsEqual<ARSalesPrice.inventoryID>>
            .And<ARSalesPrice.priceType.IsEqual<PriceTypeList.customer>>
            >
            .Where<Customer.status.IsEqual<CustomerStatus.active>.And<InventoryItem.itemStatus.IsEqual<InventoryItemStatus.active>
                .And<InventoryItem.stkItem.IsEqual<True>>
                .And<InventoryItem.isTemplate.IsEqual<False>>
                .And<ARSalesPriceExt.usrSrItemClassID.IsNull>
                .And<ARSalesPrice.breakQty.IsEqual<decimal0>>
                .And<ARSalesPrice.salesPrice.IsGreater<decimal0>>
                .And<ARSalesPrice.effectiveDate.IsLessEqual<@P.AsDateTime>>
                .And<ARSalesPrice.expirationDate.IsGreater<@P.AsDateTime>>
                >>
            .AggregateTo<GroupBy<Customer.bAccountID>, GroupBy<Location.locationID>, GroupBy<InventoryItem.inventoryID>,
            GroupBy<Location.locationCD>, GroupBy<Customer.acctCD>, GroupBy<InventoryItem.inventoryCD>, GroupBy<InventoryItem.descr>, GroupBy<InventoryItem.salesUnit>>))]
public class MYProjectionClass: IBqlTable
{
    #region Selected
    [PXBool]
    [PXDefault(false, PersistingCheck = PXPersistingCheck.Nothing)]
    [PXUIField(DisplayName = "Selected")]
    public virtual bool? Selected { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class selected : BqlBool.Field<selected> { }
    #endregion

    #region BAccountID
    [Customer(IsKey = true, DisplayName = "Customer ID", Visible = false, Enabled = false, Visibility = PXUIVisibility.Invisible, BqlField = typeof(Customer.bAccountID))]
    public virtual int? BAccountID { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class bAccountID : BqlInt.Field<bAccountID> { }
    #endregion

    #region AcctCD
    [PXDBString(30, IsUnicode = true, BqlField = typeof(Customer.acctCD))]
    [PXUIField(DisplayName = "Customer ID", Visibility = PXUIVisibility.SelectorVisible)]
    [PXDimension("BIZACCT")]
    public virtual string AcctCD { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class acctCD : BqlString.Field<acctCD> { }
    #endregion

    #region LocationID
    [PXDBInt(IsKey = true, BqlField = typeof(Location.locationID))]
    [PXUIField(DisplayName = "Location ID", Visible = false, Enabled = false, Visibility = PXUIVisibility.Invisible)]
    public virtual int? LocationID { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class locationID : BqlInt.Field<locationID> { }
    #endregion

    #region LocationCD            
    [CS.LocationRaw(typeof(Where<Location.bAccountID, Equal<Current<Location.bAccountID>>>), Visibility = PXUIVisibility.SelectorVisible, DisplayName = "Location ID", BqlField = typeof(Location.locationCD))]
    public virtual string LocationCD { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class locationCD : BqlString.Field<locationCD> { }
    #endregion

    #region InventoryID
    [PXDBInt(BqlField = typeof(InventoryItem.inventoryID))]
    [PXUIField(DisplayName = "Inventory ID", Visibility = PXUIVisibility.Visible, Visible = false)]
    public virtual int? InventoryID { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class inventoryID : BqlInt.Field<inventoryID> { }
    #endregion

    #region InventoryCD
    [InventoryRaw(IsKey = true, DisplayName = "Inventory ID", BqlField = typeof(InventoryItem.inventoryCD))]
    public virtual string InventoryCD { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class inventoryCD : BqlString.Field<inventoryCD> { }
    #endregion

    #region Descr
    [DBMatrixLocalizableDescription(Constants.TranDescLength, IsUnicode = true, BqlField = typeof(InventoryItem.descr))]
    [PXUIField(DisplayName = "Item Description", Visibility = PXUIVisibility.SelectorVisible)]
    public virtual string Descr { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class descr : BqlString.Field<descr> { }
    #endregion

    #region SalesUnit
    [INUnit(typeof(inventoryID), DisplayName = "Sales Unit", Visibility = PXUIVisibility.SelectorVisible, BqlField = typeof(InventoryItem.salesUnit))]
    public virtual string SalesUnit { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class salesUnit : BqlString.Field<salesUnit> { }
    #endregion

    #region CurrentPrice
    [PXPriceCost]
    [PXUIField(DisplayName = "Current Price")]
    public virtual decimal? CurrentPrice { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class currentPrice : BqlDecimal.Field<currentPrice> { }
    #endregion

    #region expirationDate
    [PXDBDate(BqlField = typeof(ARSalesPrice.expirationDate))]
    [PXUIField(DisplayName = "Expiration Date")]
    public virtual DateTime? ExpirationDate { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class expirationDate : BqlDateTime.Field<expirationDate> { }
    #endregion

    #region effectiveDate
    [PXDBDate(BqlField = typeof(ARSalesPrice.effectiveDate))]
    [PXUIField(DisplayName = "Effective Date")]
    public virtual DateTime? EffectiveDate { get; set; }
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Style", "IDE1006:Naming Styles", Justification = "Acumatica Standard")]
    public abstract class effectiveDate : BqlDateTime.Field<effectiveDate> { }
    #endregion
}

Its not that complicated.  And its working in that the process form loads fine. Its when selected is checked the issue happens.  I’ve done the same exact thing with different tables and it works fine. 

Only other suggestion I have is to try moving the IsKey = true to the InventoryID field instead of InventoryCD, but that really has nothing to do with the datetime2.

Same would kinda go for the ACCT field as opposed to the baccountid  but thats not anything to do with a date either. I could try moving the keys from anything integer as you say.  Not sure thats it.

Ok I found out why its happening.  Not sure on the fix.  Acumatica when you select a line in the grid runs a sql statment from the projection view (just select fields from projection view (and that is the full statment from the projection view) where and pastes in fields for the current record based on key setup in dax.     

The system pasted in @P0 which was aready in use in the projection.  so it was trying to put a currency id in the first key of the table which was integer.  Moral of the story is that, if you hit a data conversion error on selection of rows in a process screen and its a sql error according to Acumatica, then its most likely a parameter name being used twice for different fields.  

I would love to know what the fix for this is. 

I ran into the very same problem. In my case, I was able to work around it by setting every field as a key like this:

        #region SrvOrdType
        public abstract class srvOrdType : PX.Data.BQL.BqlString.Field<srvOrdType> { }
        [PXDBString(IsKey = true, BqlField = typeof(FSAppointmentDet.srvOrdType))]
        public virtual string SrvOrdType { get; set; }
        #endregion

But that’s a hacky work around. 

If anyone could shed light in the problem and the suggested fix, I would love to hear it.

@edwardmcgovern53 did you set the Projection to Persistent = true?

BTW, the  IsKey = true worked for some fields, and for some it did not. This is really a frustrating bug...

No I was just reading about Persistent = true, I stumbled on it and will get it a whirl next time I hit this.  Never saw that property before.  Thanks for the input

@edwardmcgovern53 I’m not sure what the default is. But setting that true lets Acumatica know it can be changed. So, maybe it ends up bringing another cache into play at that point? IDK. Just a thought.