c# – 使用NPOI将图像插入Excel文件

我正在尝试将图像插入excel文件.我尝试了两种不同的方法,但它们都不起作用.

//Method 1

HSSFPatriarch patriarch = newSheet.CreateDrawingPatriarch() as HSSFPatriarch;
HSSFClientAnchor anchor;
var memoryStream = new MemoryStream();
System.Drawing.Image image = System.Drawing.Image.FromFile("image.jpeg");
image.Save(memoryStream,System.Drawing.Imaging.ImageFormat.Gif);
anchor = new HSSFClientAnchor(0,255,0);
anchor.AnchorType = 2; //types are 0,2,and 3. 0 resizes within the cell,2 doesn't
int index = newWorkbook.AddPicture(memoryStream.ToArray(),PictureType.JPEG);
HSSFPicture signaturePicture = patriarch.CreatePicture(anchor,index) as HSSFPicture; //ERROR

使用方法1,当我尝试编译时捕获异常.错误消息wasObject引用未设置为对象的实例,并且错误发生在代码的最后一行.

//Method 2

byte[] data = File.ReadAllBytes("image.jpeg");
int picInd = newWorkbook.AddPicture(data,XSSFWorkbook.PICTURE_TYPE_JPEG);
XSSFCreationHelper helper = newWorkbook.GetCreationHelper() as XSSFCreationHelper;
XSSFDrawing drawing = newSheet.CreateDrawingPatriarch() as XSSFDrawing;
XSSFClientAnchor anchor = helper.CreateClientAnchor() as XSSFClientAnchor;
anchor.Col1 = 0;
anchor.Row1 = 0;
XSSFPicture pict = drawing.CreatePicture(anchor,picInd) as XSSFPicture;

方法2编译并运行没有问题.但是当我尝试打开创建的excel文件时,我收到一条消息,说Excel在’output.xlsx’中找到了不可读的内容.你想恢复这个工作簿的内容吗？我恢复了工作簿,仍然没有显示图像.

插入图像后的下一步是在同一工作簿中克隆工作表.使用方法2,根本没有创建克隆表,我不确定一旦图像问题得到修复,这是否会得到修复.

有人可以帮我这个吗？我想知道如何使方法正常工作,或者是否有另一种方法将图像插入excel文件.

另外,作为一个注释,我正在使用XSSFWorkbook,XSSFSheet等(不是HSSF),我的输出文件是.xlsx

任何帮助/建议表示赞赏,谢谢！