I am trying to pass the null value to float data type as follow,

```
float? period_final_value = null; 

```

and getting the value in **period\_final\_value** from the parsing xml string as follows

```
var action = xmlAttributeCollection_for_period["value"];
xmlActionsone[j] = action.Value;
period_final_value = float.Parse(action.Value); 

```

and then adding this obtained value to list as follows

```
serie_line.data.Add(period_final_value);

```

Defined my list as follows

```
var serie_line = new { name = series_name, data = new List<float?>() };

```

Now, My issue is when I am trying to pass value,it shold get add to the list, and moment when no value is recognized then it should add null has the value in the place of empty value in list but I don't know I am not able to get it work properly...my web service crashes moment it counters any blank value...any help will be greatly appreciated...

plz note...the var serie\_line..I am going to serialize it into JSON format so that I can use those values to plot chart.