Odtnhj

I am not much of a technical person, so excuse my terminologies. I am actually having trouble in getting data from my database in datagrid view in one of my win form. Basically, I created a query through table adapter under data source in visual studio 2017. Thing is, data is not being showed due to error appearing ["System.Data.ConstraintException: 'Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.'"] when debugged (F5).

Here's the sample sql command i used, please tell me what's wrong with it & advise what i can do to make it work.

Here's the SQL command/query i am using within table adapter name d it as "GetDataByStockRepByWH":

SELECT ItemCode, ItemName, WarehouseName, SUM(StockTotal) AS 
 StockTotal
FROM tblTransactions
WHERE (WarehouseName = @Param1)
GROUP BY ItemCode, ItemName, WarehouseName
HAVING (SUM(StockTotal) <> 0)

And this is the vb code that i am using in order to fetch data:

Private Sub GetWarehouse()

 Dim db As New DbCenterDataSetTableAdapters.tblTransactionsTableAdapter
 Dim tb = db.GetDataByStockRepByWH(cmbWarehouse.Text)
 dgvStockReport.DataSource = tb

End Sub

Also, tblTransactions have around more than 10 fields, I am only doing query for four fields. Which i need to show in my datagrid view.

While this is the screenshot of the form i am trying to get it worked.

Win form sreenshot

Looking at combobox (attached winform screenshot), aim is for datagrid view to change depending on the selection in combobox.