Question

我是C＃的新手，我试图将一些数据从C＃中的DataGridView导出到Excel文件中。 datagridview的输入由用户填写。

目前，我的程序可以创建一个excel文件以及datagridview中的值，并以给定日期作为文件名。

我的问题是我似乎无法找到从gridview附加数据的方法如果excel文件已经存在，它会覆盖当前的excel文件。

非常感谢任何帮助/提示/建议。

谢谢：）

这是我的代码：

Microsoft.Office.Interop.Excel.Application xlApp;          
Microsoft.Office.Interop.Excel.Workbook xlWorkBook; 
Microsoft.Office.Interop.Excel.Worksheet xlWorkSheet;
Microsoft.Office.Interop.Excel.Sheets xlBigSheet;
Microsoft.Office.Interop.Excel.Sheets xlSheet;
object misValue;
String newPath;

private void buttonOK_Click(object sender, EventArgs e)
{
    createXLSfile();
}

private void createXLSfile(){
    String cDate = datePicker.Value.ToShortDateString();
    String cMonth = datePicker.Value.ToString("MMMM");
    String cYear = datePicker.Value.ToString("yy");
    String cDay = datePicker.Value.ToString("dd");

    String fName = cDay + "-" + cMonth+ "-" + cYear + ".xls";

    String mainPath = @"C:\Users\User1\Desktop\" + cYear;
    String folderPath = System.IO.Path.Combine(mainPath, cMonth);
    String excelPath = System.IO.Path.Combine(folderPath, fName);

    System.IO.Directory.CreateDirectory(mainPath);
    System.IO.Directory.CreateDirectory(folderPath);

    String fNameOnly = Path.GetFileNameWithoutExtension(excelPath);
    String extension = Path.GetExtension(excelPath);
    String path = Path.GetDirectoryName(excelPath);
    newPath = excelPath;

    if(File.Exists(newPath))
    {
        existingFile();
    }else
    {
        newFile();
    }
    MessageBox.Show("Submitted");
}

private void newFile()
{
    xlApp = new Microsoft.Office.Interop.Excel.Application();
    xlApp.Visible = true;
    misValue = System.Reflection.Missing.Value;
    xlWorkBook = xlApp.Workbooks.Add(misValue);
    xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);

    xlWorkSheet = xlWorkBook.Sheets["Sheet1"];
    xlWorkSheet = xlWorkBook.ActiveSheet;
    xlWorkSheet.Name = "Sheet1";

    xlWorkSheet.Cells[2, 1] = "Header1";
    xlWorkSheet.Cells[2, 2] = "Header2";
    xlWorkSheet.Cells[2, 3] = "Total";
    getData();

    xlWorkBook.SaveAs(newFullPath, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal, misValue,
    misValue, misValue, misValue, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
    xlWorkBook.Close(true, misValue, misValue);
    xlApp.Quit();
    Marshal.ReleaseComObject(xlWorkSheet);
    Marshal.ReleaseComObject(xlWorkBook);
    Marshal.ReleaseComObject(xlApp);
}

private void existingFile()
{
    xlApp = new Microsoft.Office.Interop.Excel.Application();
    xlApp.Visible = true;
    xlWorkBook = xlApp.Workbooks.Open(newPath, 0, 
                false, 5, "", "", false, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows,
                 "", true, false, 0, true, false, false);

    xlBigSheet = xlWorkBook.Worksheets;
    string x = "Sheet1";
    xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlBigSheet.get_Item(x);

    getData();

    xlWorkBook.SaveAs(newPath, Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookNormal,
            misValue, misValue, misValue, misValue, Microsoft.Office.Interop.Excel.XlSaveAsAccessMode.xlExclusive,
            misValue, misValue, misValue,
            misValue, misValue);

    xlWorkBook.Close(misValue, misValue, misValue);
    xlWorkBook = null;
    xlApp.Quit();
    GC.WaitForPendingFinalizers();
    GC.Collect();
    GC.WaitForPendingFinalizers();
    GC.Collect();
}

private void getData()
{
    double a,b,c,d,total = 0;
    int lastRow_ = 3;

    foreach(DataGridViewRow r in dataGridView1.Rows)
    {
        if(!r.IsNewRow)
        {
            a = Convert.ToDouble(r.Cells[2].Value);
            b = Convert.ToDouble(r.Cells[3].Value);
            c = Convert.ToDouble(r.Cells[4].Value);
            d = Convert.ToDouble(r.Cells[5].Value);

            total = a + b + c + d;

            xlWorkSheet.Cells[lastRow_, 1] = "Hi";
            xlWorkSheet.Cells[lastRow_, 2] = "Hello";
            xlWorkSheet.Cells[lastRow_, 3] = Convert.ToString(total);
            lastRow_ = xlWorkSheet.Cells.Find(
                        "*",
                        xlWorkSheet.Cells[1, 1],
                        misValue,
                        Microsoft.Office.Interop.Excel.XlLookAt.xlPart,
                        Microsoft.Office.Interop.Excel.XlSearchOrder.xlByRows,
                        Microsoft.Office.Interop.Excel.XlSearchDirection.xlPrevious,
                        misValue,
                        misValue,
                        misValue).Row + 1;
        }
    }
    total = 0;
}

更新1：仍然卡住了。一直试图关注此链接： https://www.codeproject.com/articles/5123/opening-and-navigating-excel-with-c

输出

Directory of outputted excel file

This is what's inside the outputted excel file

Answer 1

当您需要将数据附加到现有工作表时，您需要找出上次使用的行的位置，并开始在此行之后添加数据。获取此“最后”行的当前代码很尴尬，因为一旦开始添加行，就会继续检查这个“最后”行，这是不必要的。 getData()方法只是将数据添加到新的excel文件中，其中最后一行无关紧要。如果文件存在，那么您只需要获取最后使用的行并开始在下一行导入数据。我猜你的代码可能会更好，发送GetData(RowToStart)方法的起始行索引并简单地增加lastRow_变量，如下所示：没有必要继续检查这个最后一行。

private void getData(int lastRow_) {
  double a, b, c, d, total = 0;
  //int lastRow_ = 4;

  foreach (DataGridViewRow r in dataGridView1.Rows) {
    //if (!row.IsNewRow) {
    if (!r.IsNewRow) {
        a = Convert.ToDouble(r.Cells[2].Value);
      b = Convert.ToDouble(r.Cells[3].Value);
      c = Convert.ToDouble(r.Cells[4].Value);
      d = Convert.ToDouble(r.Cells[5].Value);

      total = a + b + c + d;

      xlWorkSheet.Cells[lastRow_, 1] = "Hi";
      xlWorkSheet.Cells[lastRow_, 2] = "Hello";
      xlWorkSheet.Cells[lastRow_, 3] = Convert.ToString(total);
      lastRow_++;
      //lastRow_ = xlWorkSheet.Cells.Find(
      //            "*",
      //            xlWorkSheet.Cells[1, 1],
      //            misValue,
      //            Microsoft.Office.Interop.Excel.XlLookAt.xlPart,
      //            Microsoft.Office.Interop.Excel.XlSearchOrder.xlByRows,
      //            Microsoft.Office.Interop.Excel.XlSearchDirection.xlPrevious,
      //            misValue,
      //            misValue,
      //            misValue).Row + 1;
    }
  }
  total = 0;
}

如果文件是新文件，您可以像下面这样调用此方法。

 .
 .
 .
  xlWorkSheet.Cells[3, 1] = "Header1";
  xlWorkSheet.Cells[3, 2] = "Header2";
  xlWorkSheet.Cells[3, 3] = "Total";
  getData(4);
 .
 .
 .

如果文件已经存在并且您需要将数据附加到现有工作表，则需要获取最后使用的行，然后从下一行开始。您可以拨打getData(RowToStart)，如下所示。

 .
 .
 .

 xlWorkSheet = (Microsoft.Office.Interop.Excel.Worksheet)xlBigSheet.get_Item("Sheet1");
 Microsoft.Office.Interop.Excel.Range last = xlWorkSheet.Cells.SpecialCells(Microsoft.Office.Interop.Excel.XlCellType.xlCellTypeLastCell, Type.Missing);
 int lastUsedRow = last.Row;
 getData(lastUsedRow + 1);
 .
 .
 .

我希望这是有道理的。

使用C＃将数据附加到现有Excel文件

1 个答案: