数据查询后如果结果为空，应该怎么判断呢？

[u013538133]

 dbconn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=d:\我的文档\Visual Studio 2005\Visualizers\WebSites\WebSite3\成绩单.mdb");
        dbconn.Open();

        da = new OleDbDataAdapter(@"SELECT xuesheng.Num_xuesheng, xuesheng.Name_xuesheng, kecheng.Name_kecheng, banji.Name_banji, xuanke.Chengji_xuanke, xuanke.Date_xuanke FROM (banji INNER JOIN ((xuesheng INNER JOIN xuanke ON xuesheng.Num_xuesheng = xuanke.XueshengNum_xuanke) INNER JOIN kecheng ON xuanke.KechengNum_xuanke = kecheng.Num_kecheng) ON banji.Num_banji = xuanke.BanjiNum_xuanke) " + tiaojian, dbconn);
        DataSet di = new DataSet();
        da.Fill(di);
  
        GridView1.DataSource = di;
        GridView1.DataBind();
        dbconn.Close();

应该判断哪个值？

[yyl8781697]

if(di.Tables[0].Rows.Count>0)//判断dataset数据集中的第一个datatable是否有行数据
{
   //有数据
}

[漫天雪飞]

if(di != null && di.Tables[0].Rows.Count>0)

[zhu0816]

判断dataset是否为空吧

[iilrain]

引用 2 楼 xue529290400 的回复:

if(di != null && di.Tables[0].Rows.Count>0)

这样可以

[what是个穷孩纸]

引用 4 楼 iilrain 的回复:

[quote=引用 2 楼 xue529290400 的回复:] if(di != null && di.Tables[0].Rows.Count>0)

这样可以[/quote] 正解

[zj25810]

你的da执行完了da = new OleDbDataAdapter(@"SELECT xuesheng.Num_xuesheng, xuesheng.Name_xuesheng, kecheng.Name_kecheng, banji.Name_banji, xuanke.Chengji_xuanke, xuanke.Date_xuanke FROM (banji INNER JOIN ((xuesheng INNER JOIN xuanke ON xuesheng.Num_xuesheng = xuanke.XueshengNum_xuanke) INNER JOIN kecheng ON xuanke.KechengNum_xuanke = kecheng.Num_kecheng) ON banji.Num_banji = xuanke.BanjiNum_xuanke) " + tiaojian, dbconn); 后是个什么样的值？如果能判断da有错，那就 DataSet di = new DataSet(); da.Fill(di); GridView1.DataSource = di; GridView1.DataBind(); 这几步全省了。

[taozi_5188]

引用 2 楼 xue529290400 的回复:

if(di != null && di.Tables[0].Rows.Count>0)

正解