DataRelations

[Roey]

Hi, can't get my dataRelations to work. I have an n-tier app with an application layer calling a dataset from the lower levels:

 

Dim objRoutingMaster As New elantis_BUS.BusRoutingMaster()

Dim objWorkCentre As New elantis_BUS.BusWorkCentre()

Dim dsReturn As New DataSet()

 

Sub 1

 

dsReturn = objRoutingMaster.All

 

Sub 2

 

dsReturn = objWorkCentre.All

 

 

Data Acces Layer 1

 

myOleDbDataAdapter.Fill(dsReturn, "Routings")

 

Data Access Layer 2

 

myOleDbDataAdapter.Fill(dsReturn, "WorkCentre")

 

 

Back at the presentation tier

 

Dim WorkCentre As New DataRelation("WorkCentre", Me.dsReturn.Tables("Routings").Columns("WCID"), Me.dsReturn.Tables("WorkCentre").Columns("WCID"))

 

dsRoutingMaster.Relations.Add(WorkCentre)

 

 

I am getting an error stating that the object reference is not set. It seems to me as that when I call the dataadapter for the second time instead of adding another table to the dataset, it is overwriting the complete dataset.

 

What am I doing wrong ????

[karimgarza]

as far as objRoutingMaster.All and objWorkCentre.All they need to return a datatable and then you can added it to the same dataset.

and then you can add it the following way:

 

dsReturn.Tables.Add(objRoutingMaster.All)
dsReturn.Tables.Add(objWorkCentre.All)

 

now if you can't modified the functions to return datatables you can do the following:

 

dsReturn.Tables.Add(objRoutingMaster.All.Tables(0))
dsReturn.Tables.Add(objWorkCentre.All.Tables(0))

 

or change the 0's for the table name

 

Best of Luck

[Roey]

Thanks for your help

 

I have to pass the data as I Dataset as I am using a dataadpater in the Data Access Layer.

 

Tried the following command:

 

Me.dsWorkCentre.Tables.Add(objWorkCentre.All.Tables("WorkCentre"))

 

and got the error message:

 

DataTable already belongs to another DataSet.