c# - "No value given for one or more required parameters"访问Excel电子表格

Question

这是我第一次使用 C# 访问和读取 excel 文件 (xlsx)..我有问题，错误是:没有为一个或多个必需参数给出值

下面是我的代码:

    private void button5_Click(object sender, EventArgs e)
    {
        string ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Class Schedules.xlsx;Extended Properties=""Excel 12.0;HDR=NO;""";
        string ExcelQuery;
        ExcelQuery = "SELECT A1 FROM [Sheet1$]"; 
        OleDbConnection ExcelConnection = new OleDbConnection(ConnectionString);
        ExcelConnection.Open();
        OleDbCommand ExcelCommand = new OleDbCommand(ExcelQuery, ExcelConnection);
        OleDbDataReader ExcelReader;
        ExcelReader = ExcelCommand.ExecuteReader(); //error happens here

        while (ExcelReader.Read())
        {
            MessageBox.Show((ExcelReader.GetValue(0)).ToString());
        }
        ExcelConnection.Close();
    }

因为这是我第一次，我只是想阅读A1的内容，下面是我的excel文件:

但是运行代码会给我一个错误:没有为一个或多个必需参数提供值。

Answer 1

好的，我找到了一种在 C# 中读取特定单元格的方法....

位置rCnt=1,cCnt=1在excel中是A1

 private void button9_Click(object sender, EventArgs e)
    {

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

        string str;
        int rCnt = 1;  // this is where you put the cell row number
        int cCnt = 1;   // this is where you put the cell column number

        xlApp = new Excel.ApplicationClass();
        xlWorkBook = xlApp.Workbooks.Open(@"C:\Class Schedules.xlsx", 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);

        range = xlWorkSheet.UsedRange;


        str = (string)(range.Cells[rCnt, cCnt] as Excel.Range).Value2; //you now have the value of A1.



        xlWorkBook.Close(true, null, null);
        xlApp.Quit();

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

    private void releaseObject(object obj)
    {
        try
        {
            System.Runtime.InteropServices.Marshal.ReleaseComObject(obj);
            obj = null;
        }
        catch (Exception ex)
        {
            obj = null;
            MessageBox.Show("Unable to release the Object " + ex.ToString());
        }
        finally
        {
            GC.Collect();
        }
    } 

一定要:

 using Excel = Microsoft.Office.Interop.Excel; 

并在名为 Microsoft Excel Object Library 的项目中添加一个引用，它可以在 COM 选项卡下找到...如果你想阅读多篇文章，只需使用 for 循环和 rCnt 或 cCnt 的增量值...如果你想写入单元格，我认为可以这样做:

(range.Cells[rCnt, cCnt] as Excel.Range).Value2 = value;

就这些了...希望这对其他人有帮助