Fill Time Error in Gride view

Dim StrOpt = IIf(IsDBNull(EGDs.Tables(0).Rows(0)("OptionalFeatures")), 0, EGDs.Tables(0).Rows(0)("OptionalFeatures"))
           Dim str As String() = StrOpt.Split(New Char() {","c}, StringSplitOptions.RemoveEmptyEntries)
           For i As Integer = 0 To str.Length - 1
               For j As Integer = 0 To GrdOpFeatures.Rows.Count - 1
                   If GrdOpFeatures.DataKeys(j).Value().ToString() = str(i).ToString() Then
                       'CType(GrdElvBuildGrp.Rows(j).FindControl("ChkOpt"), CheckBox).Checked = True
                       'Dim chk As CheckBox = DirectCast(GrdElvBuildGrp.Rows(j).FindControl("ChkOpt"), CheckBox)
                       Dim chk As CheckBox = CType(GrdElvBuildGrp.Rows(j).FindControl("ChkOpt"), CheckBox)
                       chk.Checked = True
                   End If
               Next
           Next

Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index