Handle DBNull in C#

Question

Is there a better/cleaner way to do this?

int stockvalue = 0;
if (!Convert.IsDBNull(reader[\"StockValue\"]))
    stockvalue = (int)reader[\"StockValue\"];
         


        

Answer 1

I have two following extension methods in my project:

    public static T GetValueSafe(this IDataReader dataReader, string columnName, Func valueExtractor)
        where T : class 
    {
        T value;
        if (dataReader.TryGetValueSafe(columnName, valueExtractor, out value))
        {
            return value;
        }

        return null;
    }

    public static bool TryGetValueSafe(this IDataReader dataReader, string columnName, Func valueExtractor, out T value)
    {
        int ordinal = dataReader.GetOrdinal(columnName);

        if (!dataReader.IsDBNull(ordinal))
        {
            // Get value.
            value = valueExtractor.Invoke(dataReader, ordinal);

            return true;
        }

        value = default(T);
        return false;
    }

The usage can be like this:

string companyName = dataReader.GetValueSafe("CompanyName", (reader, ordinal) => reader.GetString(ordinal));