如何使用 itextSharp 将多个图表 asp.net 导出到单个文档 PDF?

How to export multiple charts asp.net to a single document PDF using itextSharp?

我想使用 iTextSharp 将两个图表 Asp.net 导出到单个文档 PDF。

对于一张图表,我可以做到:

Document pdfDoc = new Document(PageSize.A4, 10f, 10f, 10f, 0f);
PdfWriter.GetInstance(pdfDoc, Response.OutputStream);
pdfDoc.Open();
using (MemoryStream stream = new MemoryStream())
{
    Chart1.SaveImage(stream, ChartImageFormat.Png);
    iTextSharp.text.Image chartImage = iTextSharp.text.Image.GetInstance(stream.GetBuffer());
    chartImage.ScalePercent(75f);
    pdfDoc.Add(chartImage);
    pdfDoc.Close();

    Response.ContentType = "application/pdf";
    Response.AddHeader("content-disposition", "attachment;filename=Charts.pdf");
    Response.Cache.SetCacheability(HttpCacheability.NoCache);
    Response.Write(pdfDoc);
    Response.End();
}

但是,我无法同时导出两个图表...

有人有答案吗?非常感谢...

也许您引用了同一张图表,或者没有清理 MemoryStream?这是一个生成两个不同图表的简单示例,然后将它们添加到 Document.

首先是生成一些示例数据的辅助方法:

byte[] GetChartImage(params int[] points)
{
    using (var stream = new MemoryStream())
    {
        using (var chart = new Chart())
        {
            chart.ChartAreas.Add(new ChartArea());
            Series s = new Series();
            for (int i = 0; i < points.Length; ++i)
            {
                s.Points.AddXY(points[i], points[i]);
            }
            chart.Series.Add(s);
            chart.SaveImage(stream, ChartImageFormat.Png);
        }
        return stream.ToArray();
    }
}

然后添加图表:

Response.ContentType = "application/pdf";
Response.AppendHeader("Content-Disposition", "attachment; filename=charts.pdf");
using (Document document = new Document())
{
    PdfWriter.GetInstance(document, Response.OutputStream);
    document.Open();
    document.Add(Image.GetInstance(GetChartImage(3, 5, 7)));
    document.Add(Image.GetInstance(GetChartImage(2, 4, 6, 8)));
}
Response.End();

PDF 输出: