/// <summary>
/// Populates <paramref name="this"/> with data read asynchronously from <paramref name="csvReader"/>.
/// </summary>
/// <remarks>
/// <para>
/// If <paramref name="this"/> has columns defined, those columns will be used when populating the data. If no columns have been defined, <paramref name="csvReader"/> must have a
/// <see cref="HeaderRecord"/>, which is then used to define the columns for <paramref name="this"/>. If any data record has more values than can fit into the columns defined on
/// <paramref name="this"/>, an exception is thrown.
/// </para>
/// </remarks>
/// <param name="this">
/// The <see cref="DataTable"/>.
/// </param>
/// <param name="csvReader">
/// The <see cref="CsvReader"/>.
/// </param>
/// <param name="maximumRecords">
/// The maximum number of records to read and add to <paramref name="this"/>.
/// </param>
/// <returns>
/// The number of rows added to <paramref name="this"/> (and therefore the number of data records read from <paramref name="csvReader"/>).
/// </returns>
public async static Task <int> FillAsync(this DataTable @this, CsvReader csvReader, int?maximumRecords)
{
@this.AssertNotNull("@this");
csvReader.AssertNotNull("csvReader");
exceptionHelper.ResolveAndThrowIf(maximumRecords.GetValueOrDefault() < 0, "maximumRecordsMustBePositive");
if (@this.Columns.Count == 0)
{
// table has no columns, so we need to use the CSV header record to populate them
exceptionHelper.ResolveAndThrowIf(csvReader.HeaderRecord == null, "noColumnsAndNoHeaderRecord");
foreach (var columnName in csvReader.HeaderRecord)
{
@this.Columns.Add(columnName);
}
}
var remaining = maximumRecords.GetValueOrDefault(int.MaxValue);
var buffer = new DataRecord[16];
while (remaining > 0)
{
var read = await csvReader.ReadDataRecordsAsync(buffer, 0, Math.Min(buffer.Length, remaining)).ConfigureAwait(false);
if (read == 0)
{
// no more data
break;
}
for (var i = 0; i < read; ++i)
{
var record = buffer[i];
exceptionHelper.ResolveAndThrowIf(record.Count > @this.Columns.Count, "moreValuesThanColumns", @this.Columns.Count, record.Count);
var recordAsStrings = new string[record.Count];
record.CopyTo(recordAsStrings, 0);
@this.Rows.Add(recordAsStrings);
}
remaining -= read;
}
return(maximumRecords.GetValueOrDefault(int.MaxValue) - remaining);
}
/// <summary>
/// Asynchronously copies all remaining records in <paramref name="this"/> to <paramref name="destination"/>.
/// </summary>
/// <param name="this">
/// The data source.
/// </param>
/// <param name="destination">
/// The data destination.
/// </param>
/// <returns>
/// The number of records written to <paramref name="destination"/>.
/// </returns>
public async static Task <int> CopyToAsync(this CsvReader @this, CsvWriter destination)
{
@this.AssertNotNull("@this");
destination.AssertNotNull("destination");
var num = 0;
var buffer = new DataRecord[16];
var read = 0;
while ((read = await @this.ReadDataRecordsAsync(buffer, 0, buffer.Length).ConfigureAwait(false)) != 0)
{
await destination.WriteRecordsAsync(buffer, 0, read).ConfigureAwait(false);
num += read;
}
return(num);
}
/// <summary>
/// Populates <paramref name="this"/> with data read asynchronously from <paramref name="csvReader"/>.
/// </summary>
/// <remarks>
/// <para>
/// If <paramref name="this"/> has columns defined, those columns will be used when populating the data. If no columns have been defined, <paramref name="csvReader"/> must have a
/// <see cref="HeaderRecord"/>, which is then used to define the columns for <paramref name="this"/>. If any data record has more values than can fit into the columns defined on
/// <paramref name="this"/>, an exception is thrown.
/// </para>
/// </remarks>
/// <param name="this">
/// The <see cref="DataTable"/>.
/// </param>
/// <param name="csvReader">
/// The <see cref="CsvReader"/>.
/// </param>
/// <param name="maximumRecords">
/// The maximum number of records to read and add to <paramref name="this"/>.
/// </param>
/// <returns>
/// The number of rows added to <paramref name="this"/> (and therefore the number of data records read from <paramref name="csvReader"/>).
/// </returns>
public async static Task<int> FillAsync(this DataTable @this, CsvReader csvReader, int? maximumRecords)
{
@this.AssertNotNull("@this");
csvReader.AssertNotNull("csvReader");
exceptionHelper.ResolveAndThrowIf(maximumRecords.GetValueOrDefault() < 0, "maximumRecordsMustBePositive");
if (@this.Columns.Count == 0)
{
// table has no columns, so we need to use the CSV header record to populate them
exceptionHelper.ResolveAndThrowIf(csvReader.HeaderRecord == null, "noColumnsAndNoHeaderRecord");
foreach (var columnName in csvReader.HeaderRecord)
{
@this.Columns.Add(columnName);
}
}
var remaining = maximumRecords.GetValueOrDefault(int.MaxValue);
var buffer = new DataRecord[16];
while (remaining > 0)
{
var read = await csvReader.ReadDataRecordsAsync(buffer, 0, Math.Min(buffer.Length, remaining)).ConfigureAwait(false);
if (read == 0)
{
// no more data
break;
}
for (var i = 0; i < read; ++i)
{
var record = buffer[i];
exceptionHelper.ResolveAndThrowIf(record.Count > @this.Columns.Count, "moreValuesThanColumns", @this.Columns.Count, record.Count);
var recordAsStrings = new string[record.Count];
record.CopyTo(recordAsStrings, 0);
@this.Rows.Add(recordAsStrings);
}
remaining -= read;
}
return maximumRecords.GetValueOrDefault(int.MaxValue) - remaining;
}
private async static Task ReadCSVFromFileAndWriteToTabDelimitedFile()
{
#region ReadCSVFromFileAndWriteToTabDelimitedFile
using (var streamReader = new StreamReader("PlanetaryData.csv"))
using (var reader = new CsvReader(streamReader))
using (var streamWriter = new StreamWriter("PlanetaryData_Modified.csv"))
using (var writer = new CsvWriter(streamWriter))
{
writer.ValueSeparator = '\t';
writer.ValueDelimiter = '\'';
// realistically, you'll probably want a larger buffer, but this suffices for demonstration purposes
var buffer = new DataRecord[4];
while (reader.HasMoreRecords)
{
var read = await reader.ReadDataRecordsAsync(buffer, 0, buffer.Length);
await writer.WriteRecordsAsync(buffer, 0, read);
}
}
#endregion
}
private async static Task ReadCSVFromFileAsynchronously()
{
#region ReadCSVFromFileAsynchronously
using (var textReader = new StreamReader("PlanetaryData.csv"))
using (var reader = new CsvReader(textReader, true))
{
await reader.ReadHeaderRecordAsync();
// realistically, you'll probably want a larger buffer, but this suffices for demonstration purposes
var buffer = new DataRecord[4];
while (reader.HasMoreRecords)
{
var read = await reader.ReadDataRecordsAsync(buffer, 0, buffer.Length);
for (var i = 0; i < read; ++i)
{
Console.WriteLine("{0} is nicknamed {1}.", buffer[i]["Name"], buffer[i]["Nickname"]);
}
}
}
#endregion
}
