Fill textboxes by clicking on DGV using BindingSource

[FastEddie]

From this thread I kind of get the idea of how to fill textboxes with records from a row by clicking on the datagridview but I have not quite got it right in practice.

My Code:

Private Sub frmEdit_Load( _
        ByVal sender As Object, _
        ByVal e As System.EventArgs) Handles Me.Load
 
        Dim da As SqlDataAdapter
        Dim ds As DataSet = New DataSet
        da = New SqlDataAdapter("Select * " & _
           "From vShowEditData Where StoreID = '" & _
           StoreID & "' Order by CategoryCode, ItemCode", Con)
        da.TableMappings.Add("Table", "EditInv")
        Try
            da.Fill(ds)
            ds.Tables("EditInv").DefaultView.AllowNew = False
            dgvEditData.DataSource = ds.Tables("EditInv")
            myBindingSource.DataSource = ds.Tables("EditInv")
        Catch ex As Exception
            MessageBox.Show( _
                ex.Message & vbNewLine & _
                ex.Source, "Data Error", _
                MessageBoxButtons.OK)
        Finally
            da.Dispose()
            ds.Dispose()
        End Try
    End Sub
 
    Private Sub dgvEditData_RowHeaderMouseDoubleClick( _
        ByVal sender As Object, _
        ByVal e As System.Windows.Forms.DataGridViewCellMouseEventArgs) _
        Handles dgvEditData.RowHeaderMouseDoubleClick
 
        tbStart.DataBindings.Add("Text", myBindingSource, "OnHandQ")
    End Sub

On the first dbl Click it sets it to 0 every time and on the second dbl Click I get this error: This causes two bindings in the collection to bind to the same property. Parameter name: binding