c# - 无法将类型 'object' 隐式转换为 'Microsoft.Office.Interop.Excel.Worksheet'

Question

我有以下类(class)。我从另一个程序中移过来创建一个 ClassLibary。

我在有 wb.Worksheeet 的任何地方都收到以下错误消息

无法将类型“对象”隐式转换为“Microsoft.Office.Interop.Excel.Worksheet”。存在显式转换(是否缺少强制转换？)

该类在原始程序中运行。我添加了引用 Inereop.Microsoft.Office.Interop.Excel

using System;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Office.Interop.Excel;
using _Excel = Microsoft.Office.Interop.Excel;

 public class Excel
    {
        string path = "";
        _Application excel = new _Excel.Application();
        Workbook wb;
        Worksheet ws;

        public Excel()
        {

        }

        public Excel(string path, int sheet)
        {
            this.path = path;
            wb = excel.Workbooks.Open(path);
            ws = wb.Worksheets[sheet];
        }

        public void Open(string path, int sheet)
        {
            this.path = path;
            wb = excel.Workbooks.Open(path);
            ws = wb.Worksheets[sheet];
        }

        public void CreateNewFile()
        {
            this.wb = excel.Workbooks.Add(XlWBATemplate.xlWBATWorksheet);
            this.ws = wb.Worksheets[1];
        }

    }
}

Answer 1

添加具有以下样式的显式类型转换:

ws = (Microsoft.Office.Interop.Excel.Worksheet)wb.Worksheets[sheet];

对于显式转换，您必须确定目标类型。 In documentation据说 Worksheets-collection 可以同时包含 Charts 和 Worksheet 对象。