目录
关于数据感应
BaseDataList 类
范例运行环境
pageview 方法
设计
实现
调用示例
数据源
调用
小结
关于数据感应
数据感应也即数据捆绑,是一种动态的,Web控件与数据源之间的交互,本文将继续介绍以与数据库提取数据并捆绑控件为例,讲解 C# 创建适用于 BaseDataList 类(如DataGrid)的通用分页数据显示方法。
BaseDataList 类
BaseDataList 类是包括如 DataList 、DataGrid 服务器控件的基类,本文我们以 DataGrid 服务器控件控件,并结合 MS SQL SERVER 和 达梦数据库,以数据分页的形式,绑定 DataGrid进行显示。
更多 BaseDataList 类的介绍请参照如下链接:
https://learn.microsoft.com/ZH-CN/dotnet/api/system.web.ui.webcontrols.basedatalist?view=netframework-4.8.1&viewFallbackFrom=net-7.0
范例运行环境
操作系统: Windows Server 2019 DataCenter
.net版本: .netFramework4.7.1 或以上
开发工具:VS2019 C#
数据提取:在这里我们以能够支持 MS SQL Server 2016、国产达梦数据 8 的通用数据库内容提取方法为例, 生成数据源需要利用 ADO.NET 中的数据提供者对象包括IDbConnection、IDbCommand、IDbDataParameter等,如何使用这些对象请参考我的文章:
《C#实现 IDbConnection / IDbCommand 等相关通用数据接口》
pageview 方法
设计
pageview 方法内置了分页函数写法(目前支持 MS SQL Server 2016 和国产达梦 8 数据库 ),另外传递SQL关键命令及配置相关参数,将数据源分页感应到指定的 BaseDataList 类控件上,其参数说明如下表:
序号 | 参数名 | 类型 | 说明 |
---|---|---|---|
1 | DbServerType | string | 目前支持 "oracle"、 "dm8",其它字符串均视为 MS SQL Server |
2 | strConn | string | 对应数据库的连接字符串 |
3 | webctls | string[] | 对应的信息标签和选择框的ID集合,如果不指定则按默认值处理,即: webctls[0]="q_pageno"; //当前页 |
4 | navsender | string | 导航按钮的 CommandArgument, nav1 表示首页,nav2 表示上一页,nav3表示下一页,nav4表示最后一页 |
5 | dbgrid | System.Web.UI.WebControls. BaseDataList | 用于捆绑 BaseDataList 的控件,如DataGrid |
6 | DisplayFieldList | string | 用于捆绑到 BaseDataList 的控件上的字段列表,以逗号进行分隔 |
7 | SelectedFieldList | string | SQL 查询语句的 select 部分,即查询字段列表,DisplayFieldList 参数是它的子集 |
8 | OrderFieldList | string | SQL 查询语句的 order by 部分,字段以逗号进行分隔 |
9 | FromTableList | string | SQL 查询语句的 from 部分,表名以逗号进行分隔 |
10 | WhereStatements | string | SQL 查询语句的 where 条件部分, 字符串需要书写 where 字样 |
11 | paras | ArrayList | 查询条件中的参数对象集合 |
12 | keyfield | string | 查询结果集的唯一标识字段,用于统计总数 |
13 | OuterFromTableList | string | 是否有用于左、右连接的表名列表 |
14 | OuterWhereStatements | string | 用于左、右连接的查询条件 |
15 | movWhereToOuter | bool | 是否用左、右连接查询条件替代where查询条件(如果需要) |
16 | GroupFuncs | ArrayList | 一组需要特殊指定的统计变量值,其添加string[]对象,string[0] 存储字段名,string[1]存储变量名 |
实现
pageview 方法完整代码如下:
public string pageview(string DbServerType,string strConn,string[] webctls,string navsender,System.Web.UI.WebControls.BaseDataList dbgrid,string DisplayFieldList,string SelectedFieldList,string OrderFieldList,string FromTableList,string WhereStatements,ArrayList paras,string keyfield,string OuterFromTableList,string OuterWhereStatements,bool movWhereToOuter,ArrayList GroupFuncs)
{string[] defaultobj=new string[5];defaultobj[0]="q_pageno"; //当前页defaultobj[1]="q_pagecount"; //页总数defaultobj[2]="q_recordcount"; //总记录数defaultobj[3]="q_pagesize"; //可选择的每页记录数defaultobj[4]="q_pageno_label"; //可选择的每页记录数if(webctls==null){webctls=defaultobj;}if(webctls.GetLength(0)<4){webctls=defaultobj;}ObjectEx oe=new ObjectEx();oe.RunAt=RunAt;oe.FindContainer=FindContainer;int _npc=0;int _now=1;try{_now=int.Parse(oe.GetBaseClassText(webctls[0]));if(oe.GetBaseClassText(webctls[1])!=""){_npc=int.Parse(oe.GetBaseClassText(webctls[1]));} }catch(Exception){_now=1;_npc=1;oe.SetBaseClassText(webctls[0],"1");oe.SetBaseClassText(webctls[1],"1");}string navtype=oe.GetBaseClassArg(navsender);if(navtype=="nav1"){_now=1;}if(navtype=="nav2"){_now--;}if(navtype=="nav3"){_now++;}if(navtype=="nav4"){_now=_npc;}if(navtype=="nav5"){_now=int.Parse(oe.GetBaseClassText(webctls[0]));}if(_now>_npc){_now=_npc;}if(_now<1){_now=1;}_now--;IDbConnection Conn = GetConnection(DbServerType, strConn);IDataReader myDr;string _countf=keyfield;string _pagesize=oe.GetBaseClassList(webctls[3],"Value");_pagesize=(_pagesize==""?"50":_pagesize);if(movWhereToOuter==true){WhereStatements=WhereStatements.Replace("where 1=1","");if(OuterWhereStatements.IndexOf("{0}")==-1){OuterWhereStatements+=" "+WhereStatements;}else{OuterWhereStatements=string.Format(OuterWhereStatements,WhereStatements);}WhereStatements="";}string groupf="",resultf="",declare="",intolist= "RecordCount";if(GroupFuncs!=null){for(int i=0;i<GroupFuncs.Count;i++){string[] rv=(string[])GroupFuncs[i];if (DbServerType.ToLower() == "dm8"){intolist += "," + rv[1] ;groupf += "," + rv[0];resultf += "," + rv[1] + " " + rv[1];declare += " " + rv[1] + " " + rv[2] + " ";}else{groupf += ",@" + rv[1] + "=" + rv[0];resultf += ",@" + rv[1] + " " + rv[1];declare += " declare @" + rv[1] + " " + rv[2] + " ";}}}string CommandText = "DECLARE @PageIndex INT "+" DECLARE @PageSize INT "+" DECLARE @RecordCount INT "+" DECLARE @PageCount INT "+declare+"SET @PageIndex="+_now.ToString()+" "+"SET @PageSize="+_pagesize+" "+"SELECT @RecordCount =COUNT("+_countf+")"+groupf+" FROM "+FromTableList+" "+WhereStatements+" "+"SET @PageCount = CEILING(@RecordCount * 1.0 / @PageSize) "+" select @recordcount rc,@pagecount pc"+resultf+" SELECT "+DisplayFieldList+" FROM "+"(SELECT "+SelectedFieldList+","+"ROW_NUMBER() OVER (ORDER BY "+OrderFieldList+") AS sn "+"FROM "+FromTableList+" "+WhereStatements+") AS T "+OuterFromTableList+" WHERE T.sn > (@PageIndex * @PageSize) and T.sn <= ((@PageIndex+1) * @PageSize) "+OuterWhereStatements;if (DbServerType.ToLower() == "dm8"){CommandText = "declare PageIndex INT; " +" PageSize INT; " +" RecordCount INT; " +" PageCount INT; " + declare +"begin SET PageIndex=" + _now.ToString() + "; " +"SET PageSize=" + _pagesize + "; " +"SELECT COUNT(" + _countf + ") " + groupf +" into "+intolist+ " FROM " + FromTableList + " " + WhereStatements + " ;" +"SET PageCount = CEILING(RecordCount * 1.0 / PageSize) ;" +" select recordcount rc,pagecount pc" + resultf +";"+" SELECT " + DisplayFieldList + " FROM " +"(SELECT " + SelectedFieldList + "," +"ROW_NUMBER() OVER (ORDER BY " + OrderFieldList + ") AS sn " +"FROM " + FromTableList + " " + WhereStatements + ") AS T " + OuterFromTableList +" WHERE T.sn > (PageIndex * PageSize) and T.sn <= ((PageIndex+1) * PageSize) " + OuterWhereStatements+" ;"+" end;";}string _info="";try{ArrayList _paras = new ArrayList();if(paras!=null){for(int i=0;i<paras.Count;i++){if (DbServerType.ToLower() == "dm8") {_paras.Add(paras[i] as DmParameter);}else{_paras.Add((SqlParameter)paras[i]);}}}IDbCommand Cmd = GetCommand(DbServerType, CommandText, _paras, Conn);Conn.Open();if (DbServerType.ToLower() == "dm8"){myDr = Cmd.ExecuteReader() as DmDataReader;}else{myDr = Cmd.ExecuteReader() as SqlDataReader;}if (myDr.Read()){ int pc=int.Parse(myDr["pc"].ToString());int rc=int.Parse(myDr["rc"].ToString());oe.SetBaseClassText(webctls[1],pc.ToString());oe.SetBaseClassText(webctls[2],rc.ToString());oe.SetBaseClassText(webctls[0],(_now+1).ToString());if(webctls.Length>4){oe.SetBaseClassText(webctls[4],(_now+1).ToString());}if(GroupFuncs!=null){for(int i=0;i<GroupFuncs.Count;i++){string[] rv=(string[])GroupFuncs[i];oe.SetBaseClassText(rv[3],myDr[rv[1]].ToString());}}}if(myDr.NextResult()){dbgrid.DataSource=myDr;dbgrid.DataBind();}myDr.Close();}catch (Exception ex){_info=ex.Message;}finally{Conn.Close();Conn.Dispose();}return _info;
}//pageview
pageview方法中涉及对控件ID在Page页面的查找 ,及对基类的一些属性如Text进行设置,因此设计了一个 ObjectEx 类,实现一些控件的查找和设置方法,该类设计如下:
序号 | 成员 | 类型 | 说明 |
---|---|---|---|
1 | public System.Web.UI.HtmlControls.HtmlForm RunAt=null; | 属性 | 运行的Form平台,Asp.net中一般只设置一个Form |
2 | public System.Web.UI.Control FindContainer=null; | 属性 | 要查找的容器,一般设置为Page |
3 | public string GetBaseClassArg(string webctl) | 方法 | 得到指定ID控件的 CommandArgument |
4 | public string GetBaseClassList(string webctl,string gettype) | 方法 | 得到指定 ID 的 ListControl 控件的Text或Value值,gettype 参数值可以设置 Text 或 Value |
5 | public string GetBaseClassText(string webctl) | 方法 | 得到指定ID控件的 Text 属性 |
6 | public void SetBaseClassText(string webctl,string values) | 方法 | 设置指定ID控件的 Text 属性 |
类代码如下:
public class ObjectEx
{public System.Web.UI.HtmlControls.HtmlForm RunAt=null;public System.Web.UI.Control FindContainer=null;public string GetBaseClassArg(string webctl){System.Web.UI.Control btnctl;btnctl=RunAt.FindControl(webctl);if(FindContainer!=null){btnctl=FindContainer.FindControl(webctl);}if(btnctl==null){return "";}if(btnctl.GetType()==typeof(System.Web.UI.HtmlControls.HtmlInputButton)){if(((System.Web.UI.HtmlControls.HtmlInputButton)btnctl).Attributes["CommandArgument"]!=null)return ((System.Web.UI.HtmlControls.HtmlInputButton)btnctl).Attributes["CommandArgument"].ToString();}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.Button)){return ((System.Web.UI.WebControls.Button)btnctl).CommandArgument;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.ImageButton)){return ((System.Web.UI.WebControls.ImageButton)btnctl).CommandArgument;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.LinkButton)){return ((System.Web.UI.WebControls.LinkButton)btnctl).CommandArgument;}return "";}public string GetBaseClassText(string webctl){System.Web.UI.Control btnctl;btnctl=RunAt.FindControl(webctl);if(FindContainer!=null){btnctl=FindContainer.FindControl(webctl);}if(btnctl==null){return "";}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.TextBox)){return ((System.Web.UI.WebControls.TextBox)btnctl).Text;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.Label)){return ((System.Web.UI.WebControls.Label)btnctl).Text;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.Button)){return ((System.Web.UI.WebControls.Button)btnctl).Text;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.LinkButton)){return ((System.Web.UI.WebControls.LinkButton)btnctl).Text;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.HyperLink)){return ((System.Web.UI.WebControls.HyperLink)btnctl).Text;}return "";}public void SetBaseClassText(string webctl,string values){System.Web.UI.Control btnctl;btnctl=RunAt.FindControl(webctl);if(FindContainer!=null){btnctl=FindContainer.FindControl(webctl);}if(btnctl==null){return;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.TextBox)){((System.Web.UI.WebControls.TextBox)btnctl).Text=values;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.Label)){((System.Web.UI.WebControls.Label)btnctl).Text=values;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.Button)){((System.Web.UI.WebControls.Button)btnctl).Text=values;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.LinkButton)){((System.Web.UI.WebControls.LinkButton)btnctl).Text=values;}if(btnctl.GetType()==typeof(System.Web.UI.WebControls.HyperLink)){((System.Web.UI.WebControls.HyperLink)btnctl).Text=values;}}public string GetBaseClassList(string webctl,string gettype){System.Web.UI.Control btnctl;btnctl=RunAt.FindControl(webctl);if(FindContainer!=null){btnctl=FindContainer.FindControl(webctl);}if(btnctl==null){return "";}return (gettype.ToLower()=="text"?((System.Web.UI.WebControls.ListControl)btnctl).SelectedItem.Text:((System.Web.UI.WebControls.ListControl)btnctl).SelectedItem.Value);}}//ObjectEx Class
调用示例
数据源
我们以 MS SQL SERVER 为例,提取信息发布系统列表信息,如下图数据显示:
表(wp_infos)设计基本情况如下表:
序号 | 字段名 | 类型 | 说明 |
---|---|---|---|
1 | title | nvarchar(200) | 信息标题 |
2 | pub_time | datetime | 发布时间 |
调用
在页面放置一个ID为 dbgrid 的 DataGrid 控件和一系列的导航按钮等控件,前端示例代码如下:
<div align="center" id="panel">
<table border="0" cellpadding="0" cellspacing="0" width="100%" style="border:1px solid #CFE2FF; border-top:2px solid #1A5FC9; background-color:#F7F9FF;" id="table310">
<tr><td align="center"><asp:DataGrid ID=dbgrid ShowHeader="True"
ShowFooter="False" CellPadding="0" Border="0" forecolor="black" Runat=server EnableViewState=True /> </td>
</tr>
<tr><td align="right"><table border="0" width="100%" cellspacing="0" cellpadding="0" id="table314" bgcolor="#EEF4FF"><tr><td align="right" valign="middle" style="display:none;"> <asp:ImageButton ID=ntop CommandArgument=nav1 OnClick=navpage ImageUrl="images/nav1.jpg" Visible="false" Runat=server/> <asp:ImageButton ID=nbtm CommandArgument=nav4 OnClick=navpage ImageUrl="images/nav4.jpg" Visible="false" Runat=server/><asp:dropdownlist id="x_pagesize" runat="server" style="font-size:9pt;font-family:宋体" Visible="false">
<asp:ListItem Text="10" Value="10" />
<asp:ListItem Text="20" Value="20" selected="true"/>
<asp:ListItem Text="30" Value="30" />
<asp:ListItem Text="40" Value="40" />
<asp:ListItem Text="50" Value="50" />
<asp:ListItem Text="100" Value="100" />
</asp:dropdownlist><asp:ImageButton Text="go" id="gotopage" Visible="false" OnClick=navpage CommandArgument=nav5 ImageUrl="images/nav5.jpg" Runat=server/></td><td width="515" height="30"></td><td valign="middle" width="100" align="right">共计<asp:Label ID=nrc Runat=server/>条记录</td><td valign="middle" width="4"><img src="../images/2012/inner/inner_dg_l.jpg"></td><td valign="middle" width="46" align="center"><asp:Label ID=ngo Text="1" Runat=server/>/<asp:Label ID=npc Runat=server/></td><td valign="middle" align="left" width="135"><asp:ImageButton ID=nprv CommandArgument=nav2 OnClick=navpage ImageUrl="../images/2012/inner/inner_dg_btn_p.jpg" Runat=server/> <asp:ImageButton ID=nnxt CommandArgument=nav3 OnClick=navpage ImageUrl="../images/2012/inner/inner_dg_btn_n.jpg" Runat=server/></td></tr></table></td></tr></table>
</div>
后端调用示例代码如下:
void navpage(Object sender,EventArgs e)
{string _sql=" title,pub_time";string _wherecon="";String arg ="";try{arg=((ImageButton)sender).CommandArgument;}catch(Exception xe){arg=((LinkButton)sender).CommandArgument;}string DisplayFieldList="sn 序号,title 标题名称,pub_time 发布时间";string SelectedFieldList=_sql;string OrderFieldList="pub_time desc";string FromTableList="wp_infos";string WhereStatements="";object[] rv=GetWhere();WhereStatements=rv[0].ToString(); string[] webctls=new string[4];webctls[0]="ngo";webctls[1]="npc";webctls[2]="nrc";webctls[3]="x_pagesize";pageview("sqlserver","您的数据连接串",webctls,((Control)sender).ID,dbgrid,DisplayFieldList,SelectedFieldList,OrderFieldList,FromTableList,WhereStatements,(ArrayList)rv[1],"id");
}
object[] GetWhere(){object[] rv=new object[2];string WhereStatements=" where 1=1 ";ArrayList paras = new ArrayList();if(q_title.Text!=""){SqlParameter para2=new SqlParameter("@title",SqlDbType.NVarChar,200);para2.Value=q_title.Text;paras.Add(para2);WhereStatements+=" and title like @title ";}if(q_pub_time1.Text!=""){SqlParameter para4=new SqlParameter("@pub_time1",SqlDbType.DateTime);para4.Value=q_pub_time1.Text;paras.Add(para4);WhereStatements+=" and pub_time>=@pub_time1 ";}if(q_pub_time2.Text!=""){SqlParameter para5=new SqlParameter("@pub_time2",SqlDbType.DateTime);para5.Value=q_pub_time2.Text;paras.Add(para5);WhereStatements+=" and pub_time<=@pub_time2 ";}rv[0]=WhereStatements;rv[1]=paras;return rv;}
小结
本方法同时适用于达梦8数据库的数据分页技术,我们可以根据自己的实际需要扩充兼容的数据库功能,范例中所需数据库驱动链接库,请下载我的资源:
https://download.csdn.net/download/michaelline/89235824
感谢您的阅读,希望本文能够对您有所帮助。