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. On googling I come to know that if the value is null in the database, SqlDataReader.GetString (or it's variants) will throw sqlnullvalueexception. What is the best coding practice for this?

if (!sqlDataReader.IsDBNull(n)) value = r.GetString(n); 

Any better way of coding?

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);