如何使用C＃ASP.NET转发器控件处理3级层次结构 [英] How to deal with 3 levels hierarchy using C# ASP.NET repeater control

问题描述

我正在使用新闻文章显示，我想按年显示这些新闻==>月份==>天 。用户界面将显示如下屏幕：

I am working with News articles display, I would like to make those news display by Years ==> Months ==> Days . The UI will display like following screen:

News 2019
 >> January (2)
     >>01/02/2019 articles
     >>01/09/2019 articles
News 2018
  >> December (2)
     >>12/02/2019 articles
     >>12/09/2019 articles
News 2017
  >> January (3)
     >>01/02/2019 articles
     >>01/09/2019 articles
News 2016
  >> January (1)
     >>01/02/2019 articles
     >>01/09/2019 articles

但我只能让它显示如下。

But I only can make it display like following.

News 2019
 >> January (2)
 
News 2018
  >> December (2)
   
News 2017
  >> January (3)

我尝试过：

What I have tried:

protected void loadyears()
   {
       con.Open();
       BindMenu();
       try {
           //Create years for news view
           SqlCommand scmdY = new SqlCommand("select distinct year([NewsDate]) as Years from [WebSiteNewsMaint] order by Years desc ", con);
           SqlDataAdapter cmdY = new SqlDataAdapter(scmdY);

           DataSet ds = new DataSet();
           cmdY.Fill(ds, "WSNewsYears");

           //Create Months  for news view
           SqlCommand scmdM = new SqlCommand("select top(100) percent Datename(month,newsdate) as NMDate, MONTH(NewsDate) as MDate,  COUNT(Newsid) AS NArticle, year([NewsDate]) as Years from [WebSiteNewsMaint]  GROUP BY  Datename(month,newsdate) ,month(newsdate),year(newsdate) ORDER BY MONTH(NewsDate) DESC", con);
           SqlDataAdapter cmdM = new SqlDataAdapter(scmdM);
           cmdM.Fill(ds, "WSNewsMonths");

           //Create the relation between the years and months views

           ds.Relations.Add("YearMonthRelation", ds.Tables["WSNewsYears"].Columns["Years"], ds.Tables["WSNewsMonths"].Columns["Years"]);

           Years.DataSource = ds.Tables["WSNewsYears"];
           Page.DataBind();

       } catch (SqlException ex)
       {
           errormessage.Text = ex.Message.ToString();
       }
       finally
       {

       con.Close();
       }


   }

推荐答案

你已经有两个级别的工作。对于第三级，您只需要第三个表，第二个关系和另一个嵌套转发器。

You've already got two levels working. For a third level, you just need a third table, a second relationship, and another nested repeater.

const string Query = @"SELECT DISTINCT 
    Year(NewsDate) As Years 
FROM 
    WebSiteNewsMaint 
ORDER BY 
    Years DESC
;

SELECT 
    Year(NewsDate) As Years, 
    Month(NewsDate) As MDate, 
    DateName(month, NewsDate) As NMDatem, 
    Count(1) As NArticle 
FROM 
    WebSiteNewsMaint
GROUP BY
    Year(NewsDate) As Years, 
    Month(NewsDate) As MDate, 
    DateName(month, NewsDate) As NMDatem
ORDER BY
    Years DESC,
    MDate DESC
;

SELECT
    Year(NewsDate) As Years, 
    Month(NewsDate) As MDate, 
    NewsDate,
    NewsId
FROM
    WebSiteNewsMaint
ORDER BY
    Years DESC,
    MDate DESC,
    NewsDate DESC
;";

using (SqlCommand command = new SqlCommand(Query, con))
{
    SqlDataAdapter da = new SqlDataAdapter(command);
    
    // Map the three result sets to friendly names:
    // See: https://docs.microsoft.com/en-us/dotnet/framework/data/adonet/dataadapter-datatable-and-datacolumn-mappings#handling-multiple-result-sets
    da.TableMappings.Add("Table", "WSNewsYears");
    da.TableMappings.Add("Table1", "WSNewsMonths");
    da.TableMappings.Add("Table2", "WSNewsDays");
    
    DataSet ds = new DataSet();
    da.Fill(ds);
    
    // Relationship from years to months:
    ds.Relations.Add("YearMonthRelation", ds.Tables["WSNewsYears"].Columns["Years"], ds.Tables["WSNewsMonths"].Columns["Years"]);
    
    // Relationship from months to days:
    ds.Relations.Add("MonthDayRelation", 
        new[] { ds.Tables["WSNewsMonths"].Columns["Years"], ds.Tables["WSNewsMonths"].Columns["MDate"] }, 
        new[] { ds.Tables["WSNewsDays"].Columns["Years"], ds.Tables["WSNewsDays"].Columns["MDate"] });
    
    Years.DataSource = ds.Tables["WSNewsYears"];
    Page.DataBind();
}

在月嵌套转发器中放置天嵌套转发器，并绑定其<$​​ c $ c> DataSource 属性与你已经为月转发器做的一样。

Put a "days" nested repeater inside the "months" nested repeater, and bind its DataSource property in the same way that you're already doing for the "months" repeater.

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