/// <summary>
/// Get a single value of given type from the single cell of the read result;
/// Throw exception when invalid
/// </summary>
public static Type Single <Type>(this SQLiteDataReader reader, bool returnDefaultWhenEmptyForValueType = false)
{
// If there is no row and type is not nullable then throw an exception otherwise return null
bool canBeNull = !typeof(Type).IsValueType || (Nullable.GetUnderlyingType(typeof(Type)) != null);
if (!reader.HasRows)
{
reader.Close(); // Close reader
if (canBeNull || returnDefaultWhenEmptyForValueType)
{
return(default(Type));
}
else
{
throw new ArgumentException("Reader contains no value.");
}
}
object value = null;
while (reader.Read()) // Necessary to close the reading even if we have only one row
{
value = reader[0];
}
reader.Close();
if (value == DBNull.Value && canBeNull)
{
return(default(Type));
}
else
{
return(ConvertExtension.ChangeType <Type>(value));
}
}
/// <summary>
/// Extract a list of single type of values from a dr
/// </summary>
public static List <type> List <type>(this SQLiteDataReader reader) where type : IConvertible
{
// If there is no row then return null
if (!reader.HasRows)
{
reader.Close(); // Close reader
return(null);
}
// Read all the rows and get the first element of each row
List <type> list = new List <type>();
while (reader.Read()) // Necessary to close the reading even if we have only one row
// Add to return list
{
list.Add(ConvertExtension.ChangeType <type>(reader[0]));
}
reader.Close();
return(list);
}
