c# - Excel 互操作 COM 不关闭

Question

我有一些代码可以打开电子表格，读取一些值，然后关闭工作表。我需要为多个文件执行此操作。我遇到的问题是 Excel 应用程序实例没有退出，因此当我为多个文件运行我的进程时，我最终运行了几个 excel.exe 进程。有什么办法让 Excel 关闭吗？

    static void ParseFile(string file)
    {
        try
        {
            System.Console.WriteLine("parsing:" + file);
            Excel.Application excel = new Excel.Application();
            Excel.Workbook wb = excel.Workbooks.Open(file);
            Excel.Worksheet ws = wb.Worksheets[1];
            for (int i = 2; i < 27; i++)
            {
                log(ws.Cells[i, 1].Text);
            }
            wb.Close(false);                
            excel.Quit();
            excel = null;
            ws = null;
            wb = null;
        }
        catch (Exception ex)
        {
            log(ex.Message);
        }
    }

------更新 12/11/12--------仍然保持 excel 实例打开------

static void ParseFile(string file)
    {
        try
        {
            log("parsing:" + file);
            Excel.Application excel = new Excel.Application();
            Excel.Workbook wb = excel.Workbooks.Open(file);
            Excel.Worksheet ws = wb.Worksheets[1];
    //do some stuff here
            wb.Close(false);
            excel.Quit();
            GC.Collect();
            GC.WaitForPendingFinalizers();
            Marshal.FinalReleaseComObject(ws);
            Marshal.FinalReleaseComObject(wb);
            Marshal.FinalReleaseComObject(excel);                
            excel = null;
            ws = null;
            wb = null;
            System.GC.Collect();
        }
        catch (Exception ex)
        {
            log(ex.Message);
        }            
    }

Answer 1

1. 使用Marshal.FinalReleaseComObject()释放资源

2. 如果您一个接一个地读取多个文件，那么在性能方面最好只打开/关闭 Excel 应用程序 一次并将打开/关闭应用程序部分移动到单独的函数

重构代码:

static Excel.Application OpenExcel(){
    Excel.Application excel = null;
    try{
        excel = new Excel.Application();
        return excel;
    }
    catch(Exception ex){
        log(ex.Message);
        return null;
    }
}

static void ParseFile(string file)
{
    try
    {
        System.Console.WriteLine("parsing:" + file);            
        Excel.Workbook wb = excel.Workbooks.Open(file);
        Excel.Worksheet ws = wb.Worksheets[1];
        for (int i = 2; i < 27; i++)
        {
            log(ws.Cells[i, 1].Text);
        }
        wb.Close(false);    
    }
    catch (Exception ex)
    {
        log(ex.Message);
    }
    finally{
        Marshal.FinalReleaseComObject(ws);
        Marshal.FinalReleaseComObject(wb);
        ws = null;
        wb = null;
    }
}

static void CloseExcel(Excel.Application excel){
    try{
        excel.Quit();
    }
    catch(Exception ex){
        log(ex.Message);
    }
    finally{
        Marshal.FinalReleaseComObject(excel);
        excel = null;
    }
}

用法:

Excel.Application excel = OpenExcel();
if(excel != null){
    // Parse files in a loop
    ParseFile("fileName");

    // Close excel after parsing all files
    CloseExcel(excel);
}