Enumeration yielded no results - vb.net

Question

I am trying to insert/update my table using the values in the grid
Given below is the code I'm using to get the productId in the grid:
Dim prodId = From row As DataRow _
In grdSale.Rows _
Where row.Item(0).ToString <> "" _
Select row.Item(0)
I am getting productid correctly. Given below is the code to get the value in QTY column with respect to the productId:
For Each id As Long In prodId
Dim intpdt As Long
intpdt = id
intQty = (From row As DataRow In grdSale.Rows Where _
row.Item(0).Equals(intpdt) _
Select row.Item("QTY")).FirstOrDefault()
Next
In intQty I am getting 0 but it should be 10 or 12 as you can see in the QTY column in the grid (Enumeration yielded no results).
Where am wrong?

Answer 1

Try doing this and see if you get the result you expected:
intQty = _
( _
From row As DataRow In grdSale.Rows Where _
CLng(row.Item(0)) = intpdt _
Select CInt(row.Item("QTY")) _
).FirstOrDefault()

Answer 2

Not sure what causes your issue, but you should use the Field extension method since it is strongly typed and supports nullable types. I also don't understand why you need the additional loop and query to find the quantity of each product. This should do both:
Dim prodQTYs = From row In grdSale.Rows.Cast(Of DataRow)()
Let ProductID = row.Field(Of String)("ProductId")
Let Quantity = row.Field(Of Long)("QTY")
Where Not String.IsNullOrWhiteSpace(ProductID)
Select New With {.ProductID = ProductID, .Quantity = Quantity}
Change the types to the appropriate ones.
Output:
For Each prodInfo In prodQTYs
Console.WriteLine("Product:{0} Quantity:{1}", prodInfo.ProductID, prodInfo.Quantity)
Next