private IEnumerable <RowInfo <T> > Take <T>(ISheet sheet, int maxErrorRows, Func <T> objectInitializer = null) where T : class
{
if (sheet == null || sheet.PhysicalNumberOfRows < 1)
{
yield break;
}
var firstRowIndex = sheet.FirstRowNum;
var firstRow = sheet.GetRow(firstRowIndex);
var targetType = typeof(T);
if (targetType == typeof(object)) // Dynamic type.
{
targetType = GetDynamicType(sheet);
MapHelper.LoadDynamicAttributes(Attributes, DynamicAttributes, targetType);
}
// Scan object attributes.
MapHelper.LoadAttributes(Attributes, targetType);
// Read the first row to get column information.
var columns = GetColumns(firstRow, targetType);
// Detect column format based on the first non-null cell.
Helper.LoadDataFormats(sheet, HasHeader ? firstRowIndex + 1 : firstRowIndex, columns, TypeFormats);
if (TrackObjects)
{
Objects[sheet.SheetName] = new Dictionary <int, object>();
}
// Loop rows in file. Generate one target object for each row.
var errorCount = 0;
foreach (IRow row in sheet)
{
if (maxErrorRows > 0 && errorCount >= maxErrorRows)
{
break;
}
if (HasHeader && row.RowNum == firstRowIndex)
{
continue;
}
var obj = objectInitializer == null?Activator.CreateInstance(targetType) : objectInitializer();
var rowInfo = new RowInfo <T>(row.RowNum, obj as T, -1, string.Empty);
LoadRowData(columns, row, obj, rowInfo);
if (rowInfo.ErrorColumnIndex >= 0)
{
errorCount++;
rowInfo.Value = default(T);
}
if (TrackObjects)
{
Objects[sheet.SheetName][row.RowNum] = rowInfo.Value;
}
yield return(rowInfo);
}
}
private IRow PopulateFirstRow(ISheet sheet, List <ColumnInfo> columns, Type type)
{
var row = sheet.CreateRow(sheet.FirstRowNum);
// Use existing column populate the first row.
if (columns != null)
{
foreach (var column in columns)
{
var cell = row.CreateCell(column.Attribute.Index);
if (!HasHeader)
{
continue;
}
SetCell(cell, column.Attribute.Name ?? column.HeaderValue, column, true);
}
return(row);
}
// If no column cached, populate the first row with attributes and object properties.
MapHelper.LoadAttributes(Attributes, type);
var attributes = Attributes.Where(p => p.Value.Property != null && p.Value.Property.ReflectedType == type);
var properties = new List <PropertyInfo>(type.GetProperties(MapHelper.BindingFlag));
// Firstly populate for those have Attribute specified.
foreach (var pair in attributes)
{
var pi = pair.Key;
var attribute = pair.Value;
if (pair.Value.Index < 0)
{
continue;
}
var cell = row.CreateCell(attribute.Index);
if (HasHeader)
{
cell.SetCellValue(attribute.Name ?? pi.Name);
}
properties.Remove(pair.Key); // Remove populated property.
}
var index = 0;
// Then populate for those do not have Attribute specified.
foreach (var pi in properties)
{
var attribute = Attributes.ContainsKey(pi) ? Attributes[pi] : null;
if (attribute?.Ignored == true)
{
continue;
}
while (row.GetCell(index) != null)
{
index++;
}
var cell = row.CreateCell(index);
if (HasHeader)
{
cell.SetCellValue(attribute?.Name ?? pi.Name);
}
else
{
new ColumnAttribute {
Index = index, Property = pi
}.MergeTo(Attributes);
}
index++;
}
return(row);
}
