SqlDataReader.GetString and sqlnullvalueexception

Question

I am new to C#. I was executing some select queries from database tables using System.Data.SqlClient classes. I got sqlnullvalueexception while executing some select query.

Answer 1

If you don't want to repeat this a lot, just create a helper function, like this:

public static class DataReaderExtensions
{
    public static string GetStringOrNull(this IDataReader reader, int ordinal)
    {
        return reader.IsDBNull(ordinal) ? null : reader.GetString(ordinal);
    }

    public static string GetStringOrNull(this IDataReader reader, string columnName)
    {
        return reader.GetStringOrNull(reader.GetOrdinal(columnName));
    }
}

Which you can call like this:

value = reader.GetStringOrNull(n);