NPOI 导出excel 通用方法

public static byte[] ExportExcel<T>(Dictionary<string, string> columnsHeader, List<T> dataSource, string title = null, string footer = null)
{
IWorkbook workbook = new HSSFWorkbook();
ISheet sheet = workbook.CreateSheet("Sheet1");
sheet.DefaultColumnWidth = 15;

IRow row;
ICell cell;

#region excel标题头
int rowIndex = 0;
if (!string.IsNullOrEmpty(title))
{
ICellStyle cellStyle = workbook.CreateCellStyle();
cellStyle.VerticalAlignment = VerticalAlignment.Center;
cellStyle.Alignment = HorizontalAlignment.Center;
IFont font = workbook.CreateFont();
font.FontHeightInPoints = 12;
font.Boldweight = 700;
cellStyle.SetFont(font);
var region = new CellRangeAddress(0, 0, 0, columnsHeader.Keys.Count > 0 ? columnsHeader.Keys.Count - 1 : 0);
sheet.AddMergedRegion(region);
//合并单元格后样式
((HSSFSheet)sheet).SetEnclosedBorderOfRegion(region, BorderStyle.Thin, NPOI.HSSF.Util.HSSFColor.Black.Index);

row = sheet.CreateRow(rowIndex);
row.HeightInPoints = 20;
cell = row.CreateCell(0);
cell.SetCellValue(title);
cell.CellStyle = cellStyle;
rowIndex++;
}
#endregion

#region 列头
row = sheet.CreateRow(rowIndex);
row.HeightInPoints = 15;
int cellIndex = 0;
foreach (var value in columnsHeader.Values)
{
ICellStyle cellStyle = workbook.CreateCellStyle();
cellStyle = workbook.CreateCellStyle();
cellStyle.BorderBottom = BorderStyle.Thin;
cellStyle.BorderLeft = BorderStyle.Thin;
cellStyle.BorderRight = BorderStyle.Thin;
cellStyle.BorderTop = BorderStyle.Thin;
//背景色
cellStyle.FillForegroundColor = HSSFColor.Grey25Percent.Index;
cellStyle.FillPattern = FillPattern.SolidForeground;
//水平垂直居中
cellStyle.VerticalAlignment = VerticalAlignment.Center;
cellStyle.Alignment = HorizontalAlignment.Center;
IFont font = workbook.CreateFont();
font.FontHeightInPoints = 10;
font.Boldweight = 700;
cellStyle.SetFont(font);

cell = row.CreateCell(cellIndex);
cell.CellStyle = cellStyle;
cell.SetCellValue(value);
cellIndex++;
}
rowIndex++;
#endregion

#region 主题内容

//单元格样式 注：不要放循环里面，NPOI中调用workbook.CreateCellStyle()方法超过4000次会报错
ICellStyle contentStyle = workbook.CreateCellStyle();
contentStyle.BorderBottom = BorderStyle.Thin;
contentStyle.BorderLeft = BorderStyle.Thin;
contentStyle.BorderRight = BorderStyle.Thin;
contentStyle.BorderTop = BorderStyle.Thin;
contentStyle.VerticalAlignment = VerticalAlignment.Center;
IFont contentFont = workbook.CreateFont();
contentFont.FontHeightInPoints = 10;
contentStyle.SetFont(contentFont);

//日期格式样式
ICellStyle dateStyle = workbook.CreateCellStyle();
dateStyle.BorderBottom = BorderStyle.Thin;
dateStyle.BorderLeft = BorderStyle.Thin;
dateStyle.BorderRight = BorderStyle.Thin;
dateStyle.BorderTop = BorderStyle.Thin;
dateStyle.VerticalAlignment = VerticalAlignment.Center;
dateStyle.SetFont(contentFont);
IDataFormat format = workbook.CreateDataFormat();
dateStyle.DataFormat = format.GetFormat("yyyy-mm-dd");
foreach (T item in dataSource)
{
row = sheet.CreateRow(rowIndex);
row.HeightInPoints = 15;
rowIndex++;
Type type = item.GetType();
PropertyInfo[] properties = type.GetProperties();
if (properties.Length > 0)
{
cellIndex = 0;
foreach (var key in columnsHeader.Keys)
{
cell = row.CreateCell(cellIndex);
cell.CellStyle = contentStyle;

if (properties.Select(x => x.Name.ToLower()).Contains(key.ToLower()))
{
var property = properties.Where(x => x.Name.ToLower() == key.ToLower()).FirstOrDefault();
string drValue = property.GetValue(item) == null ? "" : property.GetValue(item).ToString();
//当类型类似DateTime?时
var fullType = property.PropertyType.Name == "Nullable`1" ? property.PropertyType.GetGenericArguments()[0].FullName : property.PropertyType.FullName;
switch (fullType)
{
case "System.String": //字符串类型
cell.SetCellValue(drValue);
break;
case "System.DateTime": //日期类型
if (string.IsNullOrEmpty(drValue) || drValue == "0001/1/1 0:00:00")
{
cell.SetCellValue("");
}
else
{
DateTime dateV;
DateTime.TryParse(drValue, out dateV);
cell.SetCellValue(dateV);

cell.CellStyle = dateStyle; //格式化显示
}
break;
case "System.Boolean": //布尔型
bool boolV = false;
bool.TryParse(drValue, out boolV);
cell.SetCellValue(boolV);
break;
case "System.Int16": //整型
case "System.Int32":
case "System.Int64":
case "System.Byte":
int intV = 0;
int.TryParse(drValue, out intV);
cell.SetCellValue(intV);
break;
case "System.Decimal": //浮点型
case "System.Double":
double doubV = 0;
double.TryParse(drValue, out doubV);
cell.SetCellValue(doubV);
break;
case "System.DBNull": //空值处理
cell.SetCellValue("");
break;
default:
cell.SetCellValue("");
break;
}
}
cellIndex++;
}
}

}
#endregion

#region 结尾行
if (!string.IsNullOrEmpty(footer))
{
ICellStyle cellStyle = workbook.CreateCellStyle();
cellStyle.VerticalAlignment = VerticalAlignment.Center;
cellStyle.Alignment = HorizontalAlignment.Center;
IFont font = workbook.CreateFont();
font.FontHeightInPoints = 10;
font.Boldweight = 700;
cellStyle.SetFont(font);
var region = new CellRangeAddress(rowIndex, rowIndex, 0, columnsHeader.Keys.Count > 0 ? columnsHeader.Keys.Count - 1 : 0);
sheet.AddMergedRegion(region);
//合并单元格后样式
((HSSFSheet)sheet).SetEnclosedBorderOfRegion(region, BorderStyle.Thin, NPOI.HSSF.Util.HSSFColor.Black.Index);

row = sheet.CreateRow(rowIndex);
row.HeightInPoints = 18;
cell = row.CreateCell(0);
cell.SetCellValue(footer);
cell.CellStyle = cellStyle;
}
#endregion

using (MemoryStream ms = new MemoryStream())
{
workbook.Write(ms);
ms.Flush();
ms.Seek(0, SeekOrigin.Begin);
return ms.ToArray();

//或者直接导出不用返回值　　var response = System.Web.HttpContext.Current.Response;
//response.ContentEncoding = System.Text.Encoding.GetEncoding("utf-8");
//response.ContentType = "application/vnd.ms-excel";
//response.AddHeader("Content-Disposition", "attachment;filename=" + fileName + ".xls");
//response.BinaryWrite(ms.ToArray());
//response.Buffer = true;
//response.Flush();
//response.End();

}
}

Dictionary<string, string> collection = new Dictionary<string, string>();
collection.Add("字段名", "显示名");
collection.Add("name", "姓名");
collection.Add("age", "年龄");
collection.Add("grade", "分数");

var byteInfo = JXUtil.ExcelHelper.ExportExcel<Student>(collection, list);
return File(byteInfo, "application/vnd.ms-excel", string.Format("记录-{0}.xls", DateTime.Now.ToString("yyyyMMddHHmm")));

//无返回值直接调用    ExcelHelper.ExportExcel(collection, list, "广告位excel");