Vb.Net DataRelation 'column' argument cannot be null. Parameter name column -


i have query display results follows: enter image description here

now want display these results in tree view in vb.net using datarelation. add groupid parent , other details children in tree view. have done using loop, interested in doing via datarelation property of datatables. first create new table distinct groupid follows: 

dim tbl datatable = dsdataset.tables("groups").defaultview.totable(true, "groupid")

then add table dataset able add datarelation.

tbl.tablename = "aaa" dsdataset.tables.add("aaa")

and add datarelation between new table , original table:

 dim rel new datarelation("model", dsdataset.tables("aaa").columns("groupid"), dsdataset.tables("groups").columns("groupid"))

after running code , when part of creating relation following error occures: 

'column' argument cannot null. parameter name column

how can solve problem?

i think problem here...

 tbl.tablename = "aaa"  dsdataset.tables.add("aaa") 'your not adding table...

try instead...

 dsdataset.tables.add(tbl)

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