/// ///////////////////////////////////////////////////////////////////////
/// ReadData
/// <summary>
///
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="fileName">
/// Name of the file associated with the stream.
/// null if there is no such file.
/// Used solely when throwing an exception.
/// </param>
/// <param name="stream">
/// All data is read from this stream.
///
/// This is a StreamReader rather then a TextReader,
/// because we need to be able to seek back to the start of the
/// stream, and you can't do that with a TextReader (or s StringReader).
/// </param>
/// <param name="fileDescription"></param>
/// <returns></returns>
private IEnumerable <T> ReadData <T>(
string fileName,
StreamReader stream,
CsvFileDescription fileDescription) where T : class, new()
{
// If T implements IDataRow, then we're reading raw data rows
bool readingRawDataRows = typeof(IDataRow).IsAssignableFrom(typeof(T));
// The constructor for FieldMapper_Reading will throw an exception if there is something
// wrong with type T. So invoke that constructor before you open the file, because if there
// is an exception, the file will not be closed.
//
// If T implements IDataRow, there is no need for a FieldMapper, because in that case we're returning
// raw data rows.
FieldMapper_Reading <T> fm = null;
if (!readingRawDataRows)
{
fm = new FieldMapper_Reading <T>(fileDescription, fileName, false);
}
// -------
// Each time the IEnumerable<T> that is returned from this method is
// accessed in a foreach, ReadData is called again (not the original Read overload!)
//
// So, open the file here, or rewind the stream.
bool readingFile = !string.IsNullOrEmpty(fileName);
if (readingFile)
{
stream = new StreamReader(
fileName,
fileDescription.TextEncoding,
fileDescription.DetectEncodingFromByteOrderMarks);
}
else
{
// Rewind the stream
if ((stream == null) || (!stream.BaseStream.CanSeek))
{
throw new BadStreamException();
}
stream.BaseStream.Seek(0, SeekOrigin.Begin);
}
// ----------
CsvStream cs = new CsvStream(stream, null, fileDescription.SeparatorChar);
// If we're reading raw data rows, instantiate a T so we return objects
// of the type specified by the caller.
// Otherwise, instantiate a DataRow, which also implements IDataRow.
IDataRow row = null;
if (readingRawDataRows)
{
row = new T() as IDataRow;
}
else
{
row = new DataRow();
}
AggregatedException ae =
new AggregatedException(typeof(T).ToString(), fileName, fileDescription.MaximumNbrExceptions);
try
{
bool firstRow = true;
while (cs.ReadRow(ref row))
{
// Skip empty lines.
// Important. If there is a newline at the end of the last data line, the code
// thinks there is an empty line after that last data line.
if ((row.Count == 1) &&
((row[0].Value == null) ||
(string.IsNullOrEmpty(row[0].Value.Trim()))))
{
continue;
}
if (firstRow && fileDescription.FirstLineHasColumnNames)
{
if (!readingRawDataRows)
{
fm.ReadNames(row);
}
}
else
{
T obj = default(T);
try
{
if (readingRawDataRows)
{
obj = row as T;
}
else
{
obj = fm.ReadObject(row, ae);
}
}
catch (AggregatedException ae2)
{
// Seeing that the AggregatedException was thrown, maximum number of exceptions
// must have been reached, so rethrow.
// Catch here, so you don't add an AggregatedException to an AggregatedException
throw ae2;
}
catch (Exception e)
{
// Store the exception in the AggregatedException ae.
// That way, if a file has many errors leading to exceptions,
// you get them all in one go, packaged in a single aggregated exception.
ae.AddException(e);
}
yield return(obj);
}
firstRow = false;
}
}
finally
{
if (readingFile)
{
stream.Close();
}
// If any exceptions were raised while reading the data from the file,
// they will have been stored in the AggregatedException ae.
// In that case, time to throw ae.
ae.ThrowIfExceptionsStored();
}
}
/// ///////////////////////////////////////////////////////////////////////
/// ReadObject
///
/// <summary>
/// Creates an object of type T from the data in row and returns that object.
///
/// </summary>
/// <param name="row"></param>
/// <param name="ae"></param>
/// <returns></returns>
public T ReadObject(IDataRow row, AggregatedException ae)
{
if (row.Count > IndexToInfo.Length)
{
// Too many fields
throw new TooManyDataFieldsException(typeof(T).ToString(), row[0].LineNbr, FileName);
}
// -----
T obj = new T();
for (int i = 0; i < row.Count; i++)
{
TypeFieldInfo tfi = IndexToInfo[i];
if (FileDescription.EnforceCsvColumnAttribute &&
(!tfi.HasColumnAttribute))
{
// enforcing column attr, but this field/prop has no column attr.
// So there are too many fields in this record.
throw new TooManyNonCsvColumnDataFieldsException(typeof(T).ToString(), row[i].LineNbr, FileName);
}
// -----
if ((!FileDescription.FirstLineHasColumnNames) &&
(tfi.Index == CsvColumnAttribute.McDefaultFieldIndex))
{
// First line in the file does not have field names, so we're
// depending on the FieldIndex of each field in the type
// to ensure each value is placed in the correct field.
// However, now hit a field where there is no FieldIndex.
throw new MissingFieldIndexException(typeof(T).ToString(), row[i].LineNbr, FileName);
}
// -----
// value to put in the object
string value = row[i].Value;
if (value == null)
{
if (!tfi.CanBeNull)
{
ae.AddException(
new MissingRequiredFieldException(
typeof(T).ToString(),
tfi.Name,
row[i].LineNbr,
FileName));
}
}
else
{
try
{
Object objValue;
// Normally, either tfi.typeConverter is not null,
// or tfi.parseNumberMethod is not null.
//
if (tfi.TypeConverter != null)
{
objValue = tfi.TypeConverter.ConvertFromString(
null,
FileDescription.FileCultureInfo,
value);
}
else if (tfi.ParseNumberMethod != null)
{
objValue =
tfi.ParseNumberMethod.Invoke(
tfi.FieldType,
new Object[] {
value,
tfi.InputNumberStyle,
FileDescription.FileCultureInfo
});
}
else
{
// No TypeConverter and no Parse method available.
// Try direct approach.
objValue = value;
}
if (tfi.MemberInfo is PropertyInfo)
{
((PropertyInfo)tfi.MemberInfo).SetValue(obj, objValue, null);
}
else
{
((FieldInfo)tfi.MemberInfo).SetValue(obj, objValue);
}
}
catch (Exception e)
{
if (e is TargetInvocationException)
{
e = e.InnerException;
}
if (e is FormatException)
{
e = new WrongDataFormatException(
typeof(T).ToString(),
tfi.Name,
value,
row[i].LineNbr,
FileName,
e);
}
ae.AddException(e);
}
}
}
// Visit any remaining fields in the type for which no value was given
// in the data row, to see whether any of those was required.
// If only looking at fields with CsvColumn attribute, do ignore
// fields that don't have that attribute.
for (int i = row.Count; i < IndexToInfo.Length; i++)
{
TypeFieldInfo tfi = IndexToInfo[i];
if (((!FileDescription.EnforceCsvColumnAttribute) ||
tfi.HasColumnAttribute) &&
(!tfi.CanBeNull))
{
ae.AddException(
new MissingRequiredFieldException(
typeof(T).ToString(),
tfi.Name,
row[row.Count - 1].LineNbr,
FileName));
}
}
return(obj);
}