txtdate=DateTime.Parse(Context.Request["txtDate"].ToString()).ToString("yyyy-MM-dd");

    <add name="DefaultDbServerConnection" connectionString="server=服务器地址;database=数据库名称;uid=sa;pwd=数据库密码;" providerName="System.Data.SqlClient" />  

    //类调用：  
    string connectionString = ConfigurationManager.ConnectionStrings["DefaultDbServerConnection"].ConnectionString;  

sql语句按2011-12-01日期查询

    select * from History where convert(varchar(10),STime,120)='2011-12-01'  

    select * from History where datediff(dd,STime,'2011-12-01')=0  


    select * from History where STime>='2011-12-1 00:00:00.000' and STime<='2011-12-1 23:59:59.997'  

最近新接触可空类型，工作中写了这么一个对象类，其中有一个属性字段是这样子的

        /// <summary>  
        /// 取样日期时间  
        /// </summary>  
        private DateTime? samdate;  
       public DateTime? SamDate  
       {  
           get { return samdate; }  
           set { samdate = value; }  

       }  

//最终在UI层赋值后，显示时，一直不出现，最终原因原来是  
//DateTime?为可空，如果不空，得先转换为string，然后将string转换为DateTime，在将DateTime转换为你想要的格式的string串，  
//感觉非常麻烦，具体方法如下  
 string strdate = DateTime.Parse(modSamVouch.SamDate.ToString()).ToString("yyyy-MM-dd")  
//亦或者我的方法  
string strdate=SamDate==null?""：DateTime.Parse（SamDate）.ToString("yyyy-MM-dd")  

Aspose.Cells.dll使用：

    public static DataTable ExeclToDataTable(string Path)  
           {  
               try  
               {  
                   DataTable dt = new DataTable();  
                   Aspose.Cells.Workbook workbook = new Workbook();  
                   workbook.Open(Path);  
                   Worksheets wsts = workbook.Worksheets;  
                   for (int i = 0; i < wsts.Count; i++)  
                   {  
                       Worksheet wst = wsts[i];  
                       int MaxR = wst.Cells.MaxRow;  
                       int MaxC = wst.Cells.MaxColumn;  
                       if (MaxR > 0 && MaxC > 0)  
                       {  
                           dt = wst.Cells.ExportDataTableAsString(0, 0, MaxR + 1, MaxC + 1, true);  
                       }  
                   }  
                   return dt;  
               }  
               catch (Exception ex)  
               {  
                   throw new Exception(ex.Message);  
               }  
           }  

在SQLSERVER中批量替换字符串的方法:

    update ProgInfo set JoinTime=replace(JoinTime,'2007-3-2','2007-03-02')