把Excel转换成DataTable，Excel2003+

在数据处理的时候，我们会Excel（包含2003、2007、2010等）转换成DataTable，以便进一步操作

1、怎么访问Excel文件呢？我们可以通过OLEDB接口访问，如下：

        private string GetConStr(string ExcelPath)
        {
            string path = ExcelPath;
            if (!File.Exists(path))
                return null;
string str2 = Path.GetExtension(path).ToLower();
            if ((str2 != ".xls") && (str2 != ".xlsx"))
                 return null;
            string str3 = "Provider = Microsoft.Jet.OLEDB.4.0; Data Source =" + path + "; Extended Properties=Excel 8.0";
            if (str2 == ".xlsx")
                str3 = "Provider = Microsoft.ACE.OLEDB.12.0; Data Source=" + path + "; Extended Properties=Excel 12.0";
            return str3;
        }

2、读取Excel的数据到DataTable

        public DataTable ExcelToDataTable(string ExcelPath)
        {
            return ExcelToDataTable(ExcelPath, null);
        }

        public DataTable ExcelToDataTable(string ExcelPath, string SheetName)
        {
            string conStr = GetConStr(ExcelPath);
            if (string.IsNullOrEmpty(conStr))
                return null;
            OleDbConnection connection = new OleDbConnection(conStr);
            connection.Open();
            if (string.IsNullOrEmpty(SheetName))
                  SheetName = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null).Rows[]["TABLE_NAME"].ToString(); 
            else if (!SheetName.Contains("$"))
                  SheetName = SheetName + "$";
            OleDbDataAdapter adapter = new OleDbDataAdapter("select * from [" + SheetName + "]", conStr);
            DataSet dataSet = new DataSet();
            adapter.Fill(dataSet, "[" + SheetName + "$]");
            connection.Close();
            return dataSet.Tables[];
        }