从EXCEL中读取文本.NET操作 EXCEL定位怎么这么麻烦,怎么都无法准确定位到某个单元格,怎么办?

//选择并打开excel表
Excel.Application objApp = new Excel.Application();
Excel.Workbook objWorkbook = default(Excel.Workbook);
Excel.Worksheet objWorksheet = default(Excel.Worksheet);
objApp.Visible = true;
objWorkbook = objApp.Workbooks.Open(".......xls");
objWorksheet = objWorkbook.Worksheets("sheet1");