Intro
我维护了一个 NPOI 的扩展(WeihanLi.Npoi)，主要用来导入导出 Excel 数据，最近有网友提出了导入 Excel 的时候解析图片的需求，于是就有了本文的探索
导入Excel 时解析图片
xls 和 xlsx 的 API 稍有不同，详细可以直接参考以下代码，实现代码如下：
public static Dictionary<CellPosition, IPictureData> GetPicturesAndPosition(this ISheet sheet)
{
var dictionary = new Dictionary<CellPosition, IPictureData>();
if (sheet.Workbook is HSSFWorkbook)
{
foreach (var shape in ((HSSFPatriarch)sheet.DrawingPatriarch).Children)
{
if (shape is HSSFPicture picture)
{
var position = new CellPosition(picture.ClientAnchor.Row1, picture.ClientAnchor.Col1);
dictionary[position] = picture.PictureData;
}
}
}
else if (sheet.Workbook is XSSFWorkbook)
{
foreach (var shape in ((XSSFDrawing)sheet.DrawingPatriarch).GetShapes())
{
if (shape is XSSFPicture picture)
{
var position = new CellPosition(picture.ClientAnchor.Row1, picture.ClientAnchor.Col1);
dictionary[position] = picture.PictureData;
}
}
}
return dictionary;
}
CellPosition 是一个自定义的结构体，表示当前单元格的位置，源码如下：
public readonly struct CellPosition : IEquatable<CellPosition>
{
public CellPosition(int row, int col)
{
Row = row;
Column = col;
}
public int Row { get; }
public int Column { get; }
public bool Equals(CellPosition other)
{
return Row == other.Row && Column == other.Column;
}
public override bool Equals(object? obj) => obj is CellPosition other && Equals(other);
public override int GetHashCode() => $"{Row}_{Column}".GetHashCode();
}
根据上面的代码，我们就可以获取到获取到所有的图片以及图片的所在位置，这样根据单元格位置去找图片信息的时候就会很方便了
导出 Excel 时设置图片
实现代码如下：
public static bool TryAddPicture(this ISheet sheet, int row, int col, byte[] pictureBytes, PictureType pictureType = PictureType.PNG)
{
if (sheet is null)
{
throw new ArgumentNullException(nameof(sheet));
}
try
{
var pictureIndex = sheet.Workbook.AddPicture(pictureBytes, pictureType);
var clientAnchor = sheet.Workbook.GetCreationHelper().CreateClientAnchor();
clientAnchor.Row1 = row;
clientAnchor.Col1 = col;
var picture = (sheet.DrawingPatriarch ?? sheet.CreateDrawingPatriarch())
.CreatePicture(clientAnchor, pictureIndex);
picture.Resize();
return true;
}
catch (Exception e)
{
Debug.WriteLine(e);
}
return false;
}
通过上面的代码我们就可以在指定的单元格设置图片，目前没有支持单元格合并操作，有需要自己进行修改
WeihanLi.Npoi
WeihanLi.Npoi 在 1.15.0 版本中增加了图片导入导出的支持，使用示例可以参考下面的单元测试：
[Theory]
[ExcelFormatData]
public async Task ImageImportExportTest(ExcelFormat excelFormat)
{
using var httpClient = new HttpClient();
var imageBytes = await httpClient.GetByteArrayAsync("https://weihanli.xyz/assets/avator.jpg");
var list = Enumerable.Range(1, 5)
.Select(x => new ImageTest() { Id = x, Image = imageBytes })
.ToList();
var excelBytes = list.ToExcelBytes(excelFormat);
var importResult = ExcelHelper.ToEntityList<ImageTest>(excelBytes, excelFormat);
Assert.NotNull(importResult);
Assert.Equal(list.Count, importResult.Count);
for (var i = 0; i < list.Count; i++)
{
Assert.NotNull(importResult[i<b style="color:transparent">本文来源gao@!dai!ma.com搞$$代^@码网*</b>]);
var result = importResult[i]!;
Assert.Equal(list[i].Id, result.Id);
Assert.NotNull(result.Image);
Assert.True(list[i].Image.SequenceEqual(result.Image));
}
}
private class ImageTest
{
public int Id { get; set; }
public byte[] Image { get; set; } = null!;
}
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转载请注明原文链接：c# NPOI 如何在指定单元格导入导出图片
转载请注明原文链接：c# NPOI 如何在指定单元格导入导出图片
