.net技术小知识点

1、repeater控件绑定时间非空判断

     

 <%#Convert.IsDBNull(Eval("Time_Ok")) ? "--" : Eval("Time_Ok")%>

2、aspx页面通过jquery选中设定值的下拉框

 

  var key=<%=locked %>;
  $("#sellcokId option[value='"+key+"']").attr("selected","selected"); 

3、jquery获取下拉框选中的值

     

 var id = $('#select_id option:selected').val();

 4、页面跳转时页面嵌套重叠问题解决方法

 

  if (window != window.top.window) {
            window.top.window.location.href = '/admin/login.aspx';
        }

 5、修改sql server 自增主键ID初始值

     DBCC CHECKIDENT ('Person',RESEED,100000000) 

 6、vs使用快捷键小集

      

        Ctrl+j 智能提示、Ctrl+e+d 对齐、 F6 生成解决方案、 Ctrl+shift+空格 显示方法参数

7、sql 根据时间查询

   

Sql Server中查询今天、昨天、本周、上周、本月、上月数据

在做Sql Server开发的时候有时需要获取表中今天、昨天、本周、上周、本月、上月等数据，这时候就需要使用DATEDIFF()函数及GetDate()函数了。
DATEDIFF ( datepart , startdate , enddate )
释义：计算时间差
datepare值：year | quarter | month | week | day | hour | minute | second | millisecond
startdate：开始日期
enddate ：结束日期
GetDate()
释义：获取当前的系统日期

下面例子中表名为tablename,条件字段名为inputdate

查询今天

SELECT * FROM tablename where DATEDIFF(day,inputdate,GETDATE())=0

查询昨天

SELECT * FROM tablename where DATEDIFF(day,inputdate,GETDATE())=1

查询本周

SELECT * FROM tablename where datediff(week,inputdate,getdate())=0

查询上周

SELECT * FROM tablename where datediff(week,inputdate,getdate())=1

查询本月

SELECT * FROM tablename where DATEDIFF(month,inputdate,GETDATE())=0

查询上月

SELECT * FROM tablename where DATEDIFF(month,inputdate,GETDATE())=1

查询本季度的

select * from T_InterViewInfo where datediff(QQ,inputdate,getdate())=0

　　

sqlserver中如何实现时间按月,日,小时分组查询
--按照月份统计
select count(id) cnt,datepart(mm,time) [Month]
from [table]
where [time] between '2007/09/08 09:10:43' and '2007/10/09 04:32:37'
group by datepart(mm,time)
--按照日统计
select count(id) cnt,datepart(dd,time) [Day]
from [table]
where time between '2007/09/08 09:10:43' and '2007/10/09 04:32:37'
group by datepart(dd,time)
--按照小时统计
select count(id) cnt,datepart(hh,time) [Hour]
from [table]
where [time] between '2007/09/08 09:10:43' and '2007/10/09 04:32:37'

group by datepart(hh,time)

==========================================================================

1、每年
select year(ordertime) AS '年',
sum(Total) '销售合计'
from order_list
group by year(ordertime)

2、每月
select year(ordertime) '年',
month(ordertime) '月',
sum(Total) '销售合计'
from order_list
group by year(ordertime),
month(ordertime)

3、每日
select year(ordertime) '年',
month(ordertime) '月',
day(ordertime) '日',
sum(Total) '销售合计'
from order_list
group by year(ordertime),
month(ordertime),
day(ordertime)

另外每日也可以这样:
select convert(char(8),ordertime,112) dt,
sum(Total) '销售合计'
from order_list
group by convert(char(8),ordertime,112)

另外，每月(年、日)的记录条数
select year(ordertime) '年',
month(ordertime) '月',
count(*) '销售记录'
from order_list
group by year(ordertime),

month(ordertime)

 

8、执行webapi项目命令

    

在cmd命令行窗口中，切换到webapi项目文件下面，输入 dotnet watch run 命令就可以将程序执行起来，就不用每一次修改完api接口，都要去重新启动项目
如（目录需要指定到具体的api项目根目录）：D:\project\rr\xx\xx\ww\api dotnet watch run 

 9、sql server maanger studio下载地址

  

https://docs.microsoft.com/zh-cn/sql/ssms/download-sql-server-management-studio-ssms?view=sql-server-2017

10、visual studio 老版本下载地址

 

https://visualstudio.microsoft.com/zh-hans/vs/older-downloads/

 11、使项目脱离svn管理

    

建一个记事本文件，然后吧这句话复制进去
for /r . %%a in (.) do @if exist "%%a\.svn" rd /s /q "%%a\.svn"
然后保存，在吧记事本文件从命名 叫 删除SVN信息.bat ，这时候要注意后缀名不是txt而是bat 了，然后双击这个批处理文件就可以解决
要在那个项目的根目录

 12、在安装是vs目录：D:\install\vs2017\Common7\IDE 里面有一个WcfTestClient.exe可执行文件，该程序可测试wcf测试客户端

 13、vscode快捷键

      

代码行向左或向右缩进:   Ctrl+[ 、 Ctrl+]

复制或剪切当前行/当前选中内容:   Ctrl+C 、 Ctrl+V

代码格式化:   Shift+Alt+F

向上或向下移动一行:   Alt+Up 或 Alt+Down

向上或向下复制一行:   Shift+Alt+Up 或 Shift+Alt+Down

在当前行下方插入一行:   Ctrl+Enter

在当前行上方插入一行:   Ctrl+Shift+Enter

14、webstorm快捷键

     

ctrl + / : 单行注释
ctrl + shift + / : 块注释
ctrl+alt+L 格式化代码
Ctrl+Shift+Up/Down 代码向上/下移动。
ctrl + d: 行复制

15、.NET CORE项目部署

        案例：https://www.cnblogs.com/w5942066/p/13411646.html

16、根据地址还原文件（图片）

      

  static public byte[] GetBytesFromUrl(string url)
        {
            byte[] b;
            HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);
            WebResponse myResp = myReq.GetResponse();
            Stream stream = myResp.GetResponseStream();
            //int i;
            using (BinaryReader br = new BinaryReader(stream))
            {
                //i = (int)(stream.Length);
                b = br.ReadBytes(500000);
                br.Close();
            }
            myResp.Close();
            return b;
        }

        static public void WriteBytesToFile(string fileName, byte[] content)
        {
            FileStream fs = new FileStream(fileName, FileMode.Create);
            BinaryWriter w = new BinaryWriter(fs);
            try
            {
                w.Write(content);
            }
            finally
            {
                fs.Close();
                w.Close();
            }
        }

 17、解决webapi项目新建的map.json文件中文乱码问题

        可通过Notepad++将其打开，然后编码方式选择utf-8编码方式

        

 18、SQLite分页

     

降序分页
Select * From CodeUsed Where CodeUsedId <=( 
Select CodeUsedId From CodeUsed Order By  CodeUsedId desc  limit 6,1 
) Order By  CodeUsedId desc limit 3


升序分页
Select * From CodeUsed Where CodeUsedId >=( 
Select CodeUsedId From CodeUsed Order By  CodeUsedId   limit 6,1 
) Order By  CodeUsedId  limit 3

//升序
Select * From 表 Where 主键ID>=(
Select 主键ID From 表 Order By 主键ID limit (pageIndex -1) * pagesize,1
) Order By 主键ID limit pagesize

//降序
Select * From 表 Where 主键ID<=(
Select 主键ID From 表 Order By 主键ID desc limit (pageIndex -1) * pagesize,1
) Order By 主键ID desc limit pagesize

通过关键字limit进行分页，limit n,m   表示跳过n行查询m条数据

或者使用 limit m offset n 同上，表示跳过n行查询m条数据

int pagesize = m = 3

int pageIndex = 1

n = (pageIndex - 1) * pagesize

 

19、操作不同服务器数据库数据

       

https://www.cnblogs.com/zhaoyl9/p/11527090.html

 20、读取文件转为byte

    

     //将一个file文件转化为byte[]
        public static byte[] GetBytesFromUrl1(string url)
        {
            byte[] b;
            FileWebRequest myReq = (FileWebRequest)WebRequest.Create(url);
            WebResponse myResp = myReq.GetResponse();
            Stream stream = myResp.GetResponseStream();
            //int i;
            using (BinaryReader br = new BinaryReader(stream))
            {
                b = br.ReadBytes(500000);
                br.Close();
            }
            myResp.Close();
            return b;
        }

 21，加密解密操作

      http://encode.chahuo.com/

22、后台系统跳转页面时，主页出现了嵌套解决方法

   

        if (window != window.top.window) {
            window.top.window.location.href = '/login.aspx';
        }

 23、使用TransactionScope进行事务回滚，只需要将代码放入到里面就行了，Complete()方法表示事务完成

   

  try
            {
                using (TransactionScope ts = new TransactionScope())
                {
                    OP_UserInfo info1 = OP_UserInfoBLL.GetModel(100);
                    info1.Remark = "测试事务";
                    OP_UserInfoBz.Update(info1);
                    int m = 0;
                    int n = 11;
                    int c = n / m;
                    Console.WriteLine(c);
                    ts.Complete();
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }

 24、asp.net导出word

    

public void Download()
        {
            Random rd = new Random();
            string fileName = DateTime.Now.ToString("yyyyMMddhhmm") + rd.Next() + ".doc";
            //存储路径
            string path = Server.MapPath(fileName);
            //创建字符输出流
            StreamWriter sw = new StreamWriter(path, true, System.Text.UnicodeEncoding.UTF8);
            //需要导出的内容
           // string str = "<html><head><title>无标题文档</title></head><body>这里放从数据库导出的word文档内容</body></html>";
            string str = "";
            str += "<html><head><title>无标题文档</title></head><body>";
            str += "<div>阅读报表</div>";
            str += "<table border='1'><tr>";
            str += "<td>20000</td>";
            str += "<td>10000</td></tr><tr>";
            str += "<td>30000</td>";
            str += "<td>30000</td><tr>";
            str += "</table></body></html>";
            //写入
            sw.Write(str);
            sw.Close();
            Response.Clear();
            Response.Buffer = true;
            this.EnableViewState = false;
            Response.Charset = "utf-8";
            Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));
            Response.ContentType = "application/octet-stream";
            Response.WriteFile(path);
            Response.Flush();
            Response.Close();
            Response.End();
        }

25、asp.net导出pdf

    

  string fileurl = Server.MapPath("/file/" + model.DailyId +"-"+ DateTime.Now.ToString("yyyyMMddHHmmss")+ ".pdf");
            string filename = model.DailyId + "-" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".pdf";
            PDFHelper pdf = new PDFHelper();
            pdf.Open(new FileStream(fileurl, FileMode.Create));
            pdf.SetBaseFont(@"C:\Windows\Fonts\SIMHEI.TTF");
            pdf.AddImage("/images/a.jpg", 0, 200, 50);
            /// <summary>
            /// 添加段落
            /// </summary>
            /// <param name="content">内容</param>
            /// <param name="fontsize">字体大小</param>
            /// <param name="Alignment">对齐方式（1为居中，0为居左，2为居右）</param>
            /// <param name="SpacingAfter">段后空行数（0为默认值）</param>
            /// <param name="SpacingBefore">段前空行数（0为默认值）</param>
            /// <param name="MultipliedLeading">行间距（0为默认值）</param>
            pdf.AddParagraph(model.DailyContent, 15, 1, 10, 0, 0);
            pdf.AddParagraph(model.Remark + "   时间：" +model.PostTime.ToString("yyyy/MM/dd HH:mm:ss"), 25, 2, 20, 0, 0);
            pdf.Close();
            //取文件大小 
            FileStream MyFileStream;
            uint FileSize1;
            MyFileStream = new FileStream(fileurl, FileMode.Open, FileAccess.Read, FileShare.None);
            int iConverTemp = Convert.ToInt32(MyFileStream.Length);
            FileSize1 = (uint)(iConverTemp);
            MyFileStream.Close();
            Response.ContentType = "APPLICATION/OCTET-STREAM";
            Response.AddHeader("Content-length", FileSize1.ToString());//下载文件长度 
            Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8));
            Response.WriteFile(fileurl);
            Response.Flush();
            Response.End();

 26、获取ip地址

     

   public static IPAddress GetIP()
        {
            NetworkInterface[] nics = NetworkInterface.GetAllNetworkInterfaces();

            foreach (NetworkInterface adapter in nics)
            {
                foreach (var uni in adapter.GetIPProperties().UnicastAddresses)
                {
                    if (uni.Address.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
                    {
                        return uni.Address;
                    }
                }
            }
            return null;
        }

 27、去掉序列化为json字符串中携带的反斜杠

       

                            string responsedata = JsonConvert.SerializeObject(obj);
                            var json = new JsonSerializer().Deserialize(new JsonTextReader(new StringReader(responsedata)));
                            string res = "{\"code\":0,\"messgae\":\"xxxx\",\"data\":" + json + "}";
                            这样最终的res 字符串就不带反斜杠了