/// <summary>
/// Given a filename, creates a suitable ImportFile object and Importer.
/// </summary>
/// <param name="importFilename"></param>
/// <returns>An Importer, or null if the type of data in the source could not be determined.</returns>
public static Importer <T> Create(string importFilename)
{
var ext = Path.GetExtension(importFilename).TrimStart('.').ToLower();
ImportFile impFile
= ext == "csv" ? (ImportFile) new CsvImportFile(importFilename)
: ext.StartsWith("xl") ? new XlsImportFile(importFilename)
: null;
return(impFile != null ? new Importer <T>(impFile) : null);
}
/// <summary>
/// Constructs an Importer object, and sets up the Target and Import fields.
/// </summary>
/// <param name="importFile">The source data</param>
public Importer(ImportFile importFile)
{
_importFile = importFile;
TargetFields = GetTargetFields().ToList();
ImportFields = ImportField <T> .Create(importFile).ToList();
// If importing directly into a DbSet, this attempts to determine the primary key property
// by looking for a property with the Key attribute. It can alternatively be set manually
// in the ImportTargetField object.
var keyField = TargetFields.FirstOrDefault(f => f.Prop.CustomAttributes.Any(a => a.AttributeType == typeof(KeyAttribute)));
if (keyField != null)
{
keyField.IsKeyField = true;
}
// Tries to guess which import fields match which target properties.
Guess();
}
/// <summary>
/// Creates a set of ImportField objects from the input source.
/// </summary>
/// <param name="inputData"></param>
/// <returns></returns>
public static IEnumerable <ImportField <T> > Create(ImportFile inputData)
{
return(inputData.FieldNames.Select(f => new ImportField <T>(f)));
}