datagridview value already exist vb - vb.net

Question

this is my code for checking if a value(from dgvlist) already exist in dgvorders, my problem is the error message only shows for the first selectedrow of the dgvlist and the rest still adds.
For Each row As DataGridViewRow In dgvOrders.Rows
For i = 0 To dgvOrders.Rows.Count - 1
If row.Cells(0).Value = dgvList.SelectedRows(i).Cells(0).Value Then
MsgBox("item already listed!", MsgBoxStyle.Critical)
Else : dgvOrders.Rows.Add(v, w, x, y, z)
End If
Exit Sub
Exit For
Next
Next

Answer 1

Because after If statement you are using End sub so once the first record is compared, It is coming out of entire sub.

Answer 2

I suggest you focus on each item in turn. You only want one For Each ... Next loop (unless you also wanted to traverse the columns).
Next get the value to test into a variable ValueFromdgvList. It should be declared as a number or string to match the value expected. I don't know if I have the right syntax or the right value in the code below. You should put a breakpoint in your code and step it so you can check that you have the expected value before starting your compare.
Finally to add a row you need to set the values to an array. Better would be to define a new DataGridViewRow and add the values to that. Finally add it to the DataGridView. But I'll leave that.
'change this as needed
Dim ValueFromdgvList As String = dgvList.SelectedRows(0).Cells(0).Value
Debug.Print(ValueFromdgvList)
Dim haveMatch As Boolean
For Each row As DataGridViewRow In dgvOrders.Rows
If row.Cells(0).Value = ValueFromdgvList Then
haveMatch = True
Exit For
End If
Next
If haveMatch Then
MsgBox("item already listed!", MsgBoxStyle.Critical)
Else
Dim ValuesArray() As Object = {v, w, x, y, z}
dgvOrders.Rows.Add(ValuesArray)
End If
We're using haveMatch because we don't want to add a new row until we've checked all the rows.