Question

foreach (ListItem li in ListBox1.Items)
{
   SqlConnection con = new SqlConnection(@"Data Source=localhost\SQLEXPRESS;Initial Catalog=PSeminar;Integrated Security=true;Trusted_Connection=Yes;MultipleActiveResultSets=true");
   const string SQL = "SELECT EventName FROM Event)";//the result of this statement to be stored in a string
   if (li.Selected = //the string)//compare here
   {
      Response.Redirect("asd.aspx?name=" + a);//at here i want to use the compared value
   }
}

我想将上述SQL语句中的详细信息存储到字符串中并与之进行比较在列表框中选择的项目。通过比较，如果它们相等，我想response.redirect比较另一页中的标签。

Answer 1

所以你需要执行那个SQL并得到结果：

const string SQL = "SELECT EventName FROM Event";   //the result of this statement to be stored in a string
List<string> eventNames = new List<string>();

// set up SQL connection and command
using(SqlConnection con = new SqlConnection(@"Data Source=localhost\SQLEXPRESS;Initial Catalog=PSeminar;Integrated Security=true;Trusted_Connection=Yes;MultipleActiveResultSets=true"))
using(SqlCommand cmd = new SqlCommand(SQL, con))
{
    con.Open();

    // get a SqlDataReader to read multiple rows
    using(SqlDataReader rdr = cmd.ExecuteReader())
    {
       // while there are more result rows.....
       while(rdr.Read())
       {
           // grab the 0-index value from the result row
           eventNames.Add(rdr.GetString(0));
       }
    }

    con.Close();
}

foreach (ListItem li in ListBox1.Items)
{
   // for each of the selected items in the ListBox - check if their .Text
   // is contained in the list of event names retrieved from the database table
   if (li.Selected && eventNames.Contains(li.Text))
   {
        Response.Redirect("asd.aspx?name=" + resultFromSQL);
   }
}

此外，由于您执行的连接和SQL似乎都不依赖于循环中的任何内容 - 不要一遍又一遍地不必要地执行此SQL语句！在循环之前执行一次并存储结果...

将sql语句的结果存储到字符串中，并将其与列表框中选择的项进行比较

1 个答案: