SQL Data Reader - handling Null column values

Question

I'm using a SQLdatareader to build POCOs from a database. The code works except when it encounters a null value in the database. For example, if the FirstName column in the database contains a null value, an exception is thrown.

employee.FirstName = sqlreader.GetString(indexFirstName); 

What is the best way to handle null values in this situation?

Answer 1

You need to check for IsDBNull:

if(!SqlReader.IsDBNull(indexFirstName)) {   employee.FirstName = sqlreader.GetString(indexFirstName); } 

That's your only reliable way to detect and handle this situation.

I wrapped those things into extension methods and tend to return a default value if the column is indeed null:

public static string SafeGetString(this SqlDataReader reader, int colIndex) {    if(!reader.IsDBNull(colIndex))        return reader.GetString(colIndex);    return string.Empty; } 

Now you can call it like this:

employee.FirstName = SqlReader.SafeGetString(indexFirstName); 

and you'll never have to worry about an exception or a null value again.