c# - 用 C# 填充 excel 表

Question

我的程序结构出了问题。每当我在我的 Windows 窗体应用程序中按下一个按钮时，我的 Excel 工作表应该用数据更新一个单元格。

这是我的代码:

using System;
using System.IO;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Excel = Microsoft.Office.Interop.Excel;
namespace Test6attendance
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {


        Excel.Application xlApp;
        Excel.Workbook xlWorkBook;
        Excel.Worksheet xlWorkSheet;

        if (File.Exists("D:\\login.xlscsharp-Excel.xls"))
        {

            object misValue = System.Reflection.Missing.Value;
            xlApp = new Excel.Application();
            xlWorkBook = xlApp.Workbooks.Open("D:\\login.xlscsharp-Excel.xls", 0, true, 5, "", "", true, Microsoft.Office.Interop.Excel.XlPlatform.xlWindows, "\t", false, false, 0, true, 1, 0);

            xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
            for (int i = 1; i < 55555; i++)
            {


                if (xlWorkSheet.Cells[i, 1] == null)
                {

                    xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
                    xlWorkSheet.Cells[i, 1] = DateTime.Now.ToString("MM/dd/ yyyy, hh:mm:ss tt");
                    xlWorkBook.SaveAs("D:\\login.xlscsharp-Excel.xls", Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
                    xlWorkBook.Close(true, misValue, misValue);
                    xlApp.Quit();

                    releaseObject(xlWorkSheet);
                    releaseObject(xlWorkBook);
                    releaseObject(xlApp);

                    MessageBox.Show("Excel file updated , you can find the file D:\\csharp-Excel.xls");

                }

            }



        }
        else
        {

            //Create New Code



            object misValue = System.Reflection.Missing.Value;


            xlApp = new Excel.Application();
            xlWorkBook = xlApp.Workbooks.Add(misValue);




            xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
            xlWorkSheet.Cells[1, 1] = DateTime.Now.ToString("MM/dd/ yyyy, hh:mm:ss tt");


            xlWorkBook.SaveAs("D:\\login.xlscsharp-Excel.xls", Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
            xlWorkBook.Close(true, misValue, misValue);
            xlApp.Quit();

            releaseObject(xlWorkSheet);
            releaseObject(xlWorkBook);
            releaseObject(xlApp);

            MessageBox.Show("Excel file created , you can find the file D:\\csharp-Excel.xls");

        }
    }
         private void releaseObject(object obj)
    {
        try
        {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
            obj = null;
        }
        catch (Exception ex)
        {
            obj = null;
            MessageBox.Show("Exception Occured while releasing object " + ex.ToString());
        }
        finally
        {
            GC.Collect();
        }
    }

    private void dateTimePicker1_ValueChanged(object sender, EventArgs e)
    {

    }
    }


}

我认为问题出在 for 循环上，它似乎不起作用。需要一些建议或引用来修复它。

Answer 1

问题出在

if (xlWorkSheet.Cells[i, 1] == null)

应该是

 if (xlWorkSheet.Cells[i, 1] == null)

由于您的第一个 if 条件检查文件是否存在 if (File.Exists("D:\\login.xlscsharp-Excel.xls"))，如果不存在则创建一个文件并分配单元格 [1,1] 的值。现在，当您第二次单击时，单元格不为空并且您的值不会更新。

试试这段代码

for (int i = 1; i < 55555; i++)
            {


                if (xlWorkSheet.Cells[i, 1] != null)
                {

                    xlWorkSheet = (Excel.Worksheet)xlWorkBook.Worksheets.get_Item(1);
                    xlWorkSheet.Cells[i, 1] = DateTime.Now.ToString("MM/dd/ yyyy, hh:mm:ss tt");
                    xlWorkBook.SaveAs("D:\\login.xlscsharp-Excel.xls", Excel.XlFileFormat.xlWorkbookNormal, misValue, misValue, misValue, misValue, Excel.XlSaveAsAccessMode.xlExclusive, misValue, misValue, misValue, misValue, misValue);
                    xlWorkBook.Close(true, misValue, misValue);
                    xlApp.Quit();

                    releaseObject(xlWorkSheet);
                    releaseObject(xlWorkBook);
                    releaseObject(xlApp);

                    MessageBox.Show("Excel file updated , you can find the file D:\\csharp-Excel.xls");
                    break;

                }

            }