将Excel图表导出为图像

Question

我编写了以下简单的C#控制台应用程序，用于从Excel工作簿导出所有图表。它工作正常，除非打开文档后图表没有滚动到，在这种情况下会生成一个空的图像文件。

using Excel = Microsoft.Office.Interop.Excel;
using System;
using System.Diagnostics;

namespace ExcelExporter
{
    class ChartExporter
    {
        const string EXPORT_TO_DIRECTORY = @"C:\Users\Sandy\Desktop\Excel\Charts";

        static void Main(string[] args)
        {
            Excel.Application app = System.Runtime.InteropServices.Marshal.GetActiveObject("Excel.Application") as Microsoft.Office.Interop.Excel.Application;

            ConsoleColor c = Console.ForegroundColor;
            Console.ForegroundColor = ConsoleColor.Green;
            Console.Write("Export To: ");
            Console.ForegroundColor = c;
            string exportPath = Console.ReadLine();

            if (exportPath == "")
                exportPath = EXPORT_TO_DIRECTORY;

            Excel.Workbook wb = app.ActiveWorkbook;

            foreach (Excel.Worksheet ws in wb.Worksheets)
            {
                Excel.ChartObjects chartObjects = (Excel.ChartObjects)(ws.ChartObjects(Type.Missing));

                foreach (Excel.ChartObject co in chartObjects)
                {
                    Excel.Chart chart = (Excel.Chart)co.Chart;
//                  app.Goto(co, true);
                    chart.Export(exportPath + @"\" + chart.Name + ".png", "PNG", false);
                }
            }

            Process.Start(exportPath);
        }
    }
}

我尝试了几次滚动到该对象的失败尝试；程序底部注释掉的行（app.Goto（co，true） ）仅适用于范围。有没有办法滚动到ChartObjects，或者以其他方式确保它们正确导出到图像？

对于测试，使用一个向下1000行的图表的工作簿（足够远，当文档打开时它们毫无疑问是看不见的）；在运行程序之前关闭并重新打开文档（一旦滚动到，图表将已呈现并存储在内存中）。




Answer 1

...NET Core 3.1使用Interop.Excel并将VS中的COM ref更改为复制本地

   private static void ExportExcelChart()
    {
        var excelApp = new excel.Application(); 
        var wb = excelApp.Workbooks.Open(@"z:\scratch\acme_inc.xlsx");
        var ws = (excel.Worksheet)wb.Sheets[1];
        var chartObjects= ws.ChartObjects() as IEnumerable;

        foreach (excel.ChartObject co in chartObjects)
        { 
            co.Select();
            excel.Chart chart = (excel.Chart)co.Chart;
            chart.Export($@"z:\{chart.Name}.png", "PNG", false);
        }
        wb.Close();
        excelApp.Quit();
    }

Answer 2

我发现下面的方法对我有用

            foreach (Excel.ChartObject co in chartObjects)
            {
                co.Select();
                Excel.Chart chart = (Excel.Chart)co.Chart;
                chart.Export(exportPath + @"\" + chart.Name + ".png", "PNG", false);
            }

Answer 3

VBA，但同样的想法可能适用于C#...

Dim co As ChartObject, sht As Worksheet, x As Long
x = 1
Set sht = ThisWorkbook.Sheets("Sheet1")
For Each co In sht.ChartObjects
    Application.Goto co.TopLeftCell, True
    co.Chart.Export "C:\_stuff\test\chart" & x & ".jpg", "JPG", False
    x = x + 1
Next co