public static List<T> GetClassFromExcel<T>(string path, int fromRow, int fromColumn, int toRow = 0, int toColumn = 0) where T: class, new()
{
if (toColumn != 0 && toColumn < fromColumn) throw new Exception("toColumn can not be less than fromColumn");
if (toRow != 0 && toRow < fromRow) throw new Exception("toRow can not be less than fromRow");
List<T> retList = new List<T>();
using (var pck = new ExcelPackage())
{
using (var stream = File.OpenRead(path))
{
pck.Load(stream);
}
//Retrieve first Worksheet
var ws = pck.Workbook.Worksheets.First();
toColumn = toColumn == 0 ? typeof(T).GetProperties().Count() : toColumn; //If the to column is empty or 0, then make the tocolumn to the count of the properties Of the class object inserted
//Read the first Row for the column names and place into a list so that
//it can be used as reference to properties
Dictionary<string, int> columnNames = new Dictionary<string, int>();
// wsRow = ws.Row(0);
var colPosition = 0;
foreach (var cell in ws.Cells[1, 1, 1, toColumn == 0 ? ws.Dimension.Columns : toColumn])
{
columnNames.Add(cell.Value.ToString(), colPosition);
colPosition++;
}
//Retrieve the type of T
Type myType = typeof(T);
//Get all the properties associated with T
PropertyInfo[] myProp = myType.GetProperties();
//Loop through the rows of the excel sheet
for (var rowNum = fromRow + 1; rowNum <= (toRow == 0 ? ws.Dimension.End.Row : toRow); rowNum++) // fromRow + 1 to read from next row after columnheader
{
//create a instance of T
//T objT = Activator.CreateInstance<T>();
T objT = new T();
// var wsRow = ws.Cells[rowNum, fromColumn, rowNum, ws.Cells.Count()]; //ws.Cells.Count() causing out of range error hence using ws.Dimension.Columns to get last column index
var wsRow = ws.Cells[rowNum, fromColumn, rowNum, ws.Dimension.Columns];
foreach (var propertyInfo in myProp)
{
var attribute = propertyInfo.GetCustomAttributes(typeof(DisplayNameAttribute), true).Cast<DisplayNameAttribute>().SingleOrDefault();
string displayName = attribute != null && !string.IsNullOrEmpty(attribute.DisplayName) ? attribute.DisplayName : propertyInfo.Name; // If DisplayName annotation not used then get property name itself
if (columnNames.ContainsKey(displayName))
{
int position = 0;
columnNames.TryGetValue(displayName, out position);
////int position = columnNames.IndexOf(propertyInfo.Name);
////To prevent an exception cast the value to the type of the property.
propertyInfo.SetValue(objT, Convert.ChangeType(wsRow[rowNum, position + 1].Value, propertyInfo.PropertyType));
}
}
retList.Add(objT);
}
}
return retList;
}
//IMPLEMENTATION DONE BY PLACING Code IT IN SEPARATE Helpers.CS file and
//Consuming it in this manner
List<CustomerExcelModel> records =
Helpers.GetClassFromExcel<CustomerExcelModel>(filelocation, 1, 1);
非常感谢提交代码的用户和 Andreas 的建议这里是完成以下更改，我是泛型新手，所以请原谅并纠正我的任何错误请在下面找到修改后的代码它可能对某人有所帮助
- 添加了Display Annotation 实体模型以与Excel 列名进行映射，以便也可以处理带有空格的列名。
- 有问题“T objT”，因为它在 for 循环之外，因此导致相同的值重复插入到 List 通过
实例化循环内部修复它，即使用“new T()”
- 通过使用“ws.Dimension.Columns”获取列计数而不是 ws.Cells.Count() 来修复列超出范围错误，因为它会导致超出范围列错误
- 用于循环遍历行数据向它添加了 +1，因为 RowNum=1 正在读取标题名称，所以对“rowNum = fromRow + 1”进行了微小的更改