C# Excel 工作表对象引用未设置为对象的实例

Question

当我以交互方式运行 SSIS 包时，在运行时在脚本任务上收到错误对象引用未设置为对象的实例。

所以我使用断点调试了代码，在一步步执行之后，代码在这一行失败objExcelWbk.Close(true, Type.Missing, Type.Missing);

我已经检查了我所有的参考资料，它们都在那里，导入也很好。

下面提供函数

public void FormatExcel_DVP(string strFinalFileName, string ExcelOutputFolder, SqlConnection Conn)
{
    Microsoft.Office.Interop.Excel.ApplicationClass objExcelApp = new Microsoft.Office.Interop.Excel.ApplicationClass();
    Microsoft.Office.Interop.Excel.Workbook objExcelWbk = default(Excel.Workbook);
    Microsoft.Office.Interop.Excel.Worksheet objWrksheet = default(Excel.Worksheet);
    string sFilePath = string.Empty;
    DataSet ds = new DataSet();
    string DVP_Name = string.Empty;
    string sFilename = string.Empty;

    int RowCount = 0;
    try
    {
        SqlCommand cmd = new SqlCommand("select distinct LTRIM(RTRIM(DVP_Name))as DVP_Name from SBBCP_DVP_SVP Order By DVP_Name", Conn);
        SqlDataAdapter _da = new SqlDataAdapter(cmd);
        _da.Fill(ds);


        if (ds.Tables[0].Rows.Count > 0)
        {
            foreach (DataRow dr in ds.Tables[0].Rows)
            {
                DVP_Name = dr[0].ToString().Trim().Replace("'", "''");
                sFilename = DVP_Name.Trim();

                sFilePath = strFinalFileName + ExcelOutputFolder.Trim() + sFilename;

                if (System.IO.File.Exists(sFilePath))
                {
                    objExcelWbk = objExcelApp.Workbooks.Open(sFilePath.Trim(), Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                    objExcelApp.DisplayAlerts = false;
                    objExcelApp.Visible = false;

                    objWrksheet = (Excel.Worksheet)objExcelWbk.Worksheets["Details"];
                    ((Microsoft.Office.Interop.Excel._Worksheet)objWrksheet).Activate();

                    Microsoft.Office.Interop.Excel.Range range;

                    range = (Excel.Range)objWrksheet.get_Range("A1:J1", Type.Missing);

                    range.Interior.ColorIndex = 15;
                    range.Interior.Pattern = Microsoft.Office.Interop.Excel.XlPattern.xlPatternSolid;
                    range.NumberFormat = "@";
                    range.HorizontalAlignment = Microsoft.Office.Interop.Excel.XlHAlign.xlHAlignCenter;
                    range.VerticalAlignment = Microsoft.Office.Interop.Excel.XlVAlign.xlVAlignCenter;
                    range.WrapText = true;
                    range.Font.Bold = true;
                    range.Font.Name = "Arial";
                    range.Font.Size = 10;
                    range.AutoFilter(1, Type.Missing, Microsoft.Office.Interop.Excel.XlAutoFilterOperator.xlAnd, Type.Missing, true);


                    RowCount = objWrksheet.UsedRange.Rows.Count;
                    range = objWrksheet.get_Range("A2:J2", "A" + RowCount + ":J" + RowCount);
                    range.WrapText = true;


                    FormatPivotTable(ref objExcelWbk, "Summary");
                    objExcelWbk.SaveAs(sFilePath, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Excel.XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                }
            }
        }
        objExcelWbk.Close(true, Type.Missing, Type.Missing);
        objExcelApp.Quit();
    }
    catch (Exception e)
    {
        throw e;
    }
}

Answer 1

在你的代码中你有

for each row
{
  if file exists 
  {
     open spreadsheet.
     do stuff
  }
}
Close spreadsheet

问题在于，您的电子表格可能从未打开过，并且它试图关闭它但尚未设置。

您应该在打开电子表格的同一范围内关闭电子表格，因此在我的伪代码中，在“做事”之后 - 因为那时，如果您打开它是因为它没有出错或死亡，您可以关闭一些东西。