Question

If I have code similar to the following:

while(myDataReader.Read())
{
  myObject.intVal = Convert.ToInt32(myDataReader["mycolumn"] ?? 0);
}

It throws the error:

Object cannot be cast from DBNull to other types.

defining intVal as a nullable int is not an option. Is there a way for me to do the above?

Answer 1

Can you use an extension method? (written off the top of my head)

public static class DataReaderExtensions 
{
    public static T Read<T>(this SqlDataReader reader, string column, T defaultValue = default(T))
    {
        var value = reader[column];

        return (T)((DBNull.Value.Equals(value))
                   ? defaultValue
                   : Convert.ChangeType(value, typeof(T)));
    }
}

You’d use it like:

while(myDataReader.Read())
{
  int i = myDataReader.Read<int>("mycolumn", 0);
}