Asp.net 错误：找不到表0

在访问数据集内容之前，您没有填充数据集，因此数据集中自然没有数据

 con.Open();
 SqlDataAdapter da4 = new SqlDataAdapter("select * from tblbooking where bookid =(select max(bookid) from tblbooking)", con);
 DataSet ds4 = new DataSet();
 pay = ds4.Tables[0].Rows[0]["costoftickets"].ToString();
 Label4.Text = "Amount to Pay : " + pay + " INR.";
 da4.Fill(ds4);
 DetailsView1.DataSource = ds4;
 DetailsView1.DataBind();
 con.Close();

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请注意，若查询未返回任何数据，则仍可能会出现错误。

很抱歉，表中有7行。正确插入是否可以调试ds4.Tables[0].Rows.Count？

con.Open(); 
SqlDataAdapter da4 = new SqlDataAdapter("select * from tblbooking where bookid =(select max(bookid) from tblbooking)", con); 
DataSet ds4 = new DataSet(); 
da4.Fill(ds4); // this needs to go before accessing the data
pay = ds4.Tables[0].Rows[0]["costoftickets"].ToString(); 
Label4.Text = "Amount to Pay : " + pay + " INR."; 
DetailsView1.DataSource = ds4; 
DetailsView1.DataBind(); 
con.Close();