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

Answer 1

This method is dependent on indexFirstName which should be the zero-based column ordinal.

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

If you don't know the column index but wan't to check a name you can use this extension method instead:

public static class DataRecordExtensions
{
    public static bool HasColumn(this IDataRecord dr, string columnName)
    {
        for (int i=0; i < dr.FieldCount; i++)
        {
            if (dr.GetName(i).Equals(columnName, StringComparison.InvariantCultureIgnoreCase))
                return true;
        }
        return false;
    }
}

And use the method like this:

if(sqlReader.HasColumn("FirstName"))
{
  employee.FirstName = sqlreader["FirstName"];
}