I am creating an application for the asp.net class that I accept. One of the pages of the application should allow the user to search for a specific student using the user name or identifier. When a student is found, the page should display student data and class schedules.
I got everything to work, except for the class schedule. The approach I took (as we learned in the class) was to get the query results through SqlDataReader and associate it with the GridView. This is done in showStudentSchedule ().
The query in this function returns the correct results when I check it for the database I created, but the grid view that displays the students' schedule does not appear on the page.
//StudentInformation.aspx
<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="StudentInformation.aspx.cs" Inherits="StudentInformation" %> <asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"> </asp:Content> <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"> <p> <asp:Label ID="Label6" runat="server" Text="Search by Last Name: "></asp:Label> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox> <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" /> <asp:DropDownList ID="DropDownList1" runat="server" onselectedindexchanged="DropDownList1_SelectedIndexChanged" AutoPostBack="True"> </asp:DropDownList> </p> <asp:Label ID="Label1" runat="server"></asp:Label> <br /> <asp:Label ID="Label2" runat="server"></asp:Label> <br /> <asp:Label ID="Label3" runat="server"></asp:Label> <br /> <asp:Label ID="Label4" runat="server"></asp:Label> <br /> <asp:Label ID="Label5" runat="server"></asp:Label> <asp:Panel ID="Panel1" runat="server"> <asp:GridView ID="GridView1" runat="server"> </asp:GridView> </asp:Panel> </asp:Content>
//StudentInformation.aspx.cs
using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Data.SqlClient; public partial class StudentInformation : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void Button1_Click(object sender, EventArgs e) { string userStr = TextBox1.Text; int userInt; bool isNum = int.TryParse(userStr, out userInt); string sqlSelectFindUserByName; if (isNum) sqlSelectFindUserByName = string.Format("SELECT LastName FROM Personal_Info JOIN Students ON Personal_Info.ID = Students.Student_ID WHERE Personal_Info.ID = '{0}'", userInt); else sqlSelectFindUserByName = string.Format("SELECT LastName FROM Personal_Info JOIN Students ON Personal_Info.ID = Students.Student_ID WHERE Personal_Info.LastName LIKE '%{0}%'", userStr); SqlConnection connection = new SqlConnection(); connection.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; SqlCommand commandFindUserByName = new SqlCommand(sqlSelectFindUserByName, connection); connection.Open(); SqlDataReader readerFindUserByName = commandFindUserByName.ExecuteReader(); DropDownList1.Items.Clear(); DropDownList1.Items.Add("Please make a selection"); while (readerFindUserByName.Read()) DropDownList1.Items.Add(readerFindUserByName["LastName"].ToString()); if (DropDownList1.Items.Count == 2) DropDownList1.SelectedIndex = 1; DropDownList1_SelectedIndexChanged(null, null); connection.Close(); } protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e) { string nameLast = DropDownList1.SelectedItem.Value; displayStudent(nameLast); } private void displayStudent(String nameLast) { clearStudentLabel(); int userInt; bool isNum = int.TryParse(nameLast, out userInt); SqlConnection connection = new SqlConnection(); connection.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; string sqlSelectFindUserInfoByName; sqlSelectFindUserInfoByName = string.Format("SELECT ID, FirstName, LastName, City, Phone FROM Personal_Info WHERE LastName LIKE '%{0}%'", nameLast); SqlCommand commandFindUserInfo = new SqlCommand(sqlSelectFindUserInfoByName, connection); connection.Open(); SqlDataReader readerFindUserInfo = commandFindUserInfo.ExecuteReader(); int i = 0; while (readerFindUserInfo.Read()) { Label1.Text = "Student ID: " + readerFindUserInfo["ID"].ToString(); Label2.Text = "First name: " + readerFindUserInfo["FirstName"].ToString(); Label3.Text = "Last name: " + readerFindUserInfo["LastName"].ToString(); Label4.Text = "City: " + readerFindUserInfo["City"].ToString(); Label5.Text = "Phone: " + readerFindUserInfo["Phone"].ToString(); } connection.Close(); showStudentSchedule(userInt); } private void showStudentSchedule(int id) { SqlConnection connection = new SqlConnection(); connection.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; string sqlSelectFindUserInfoByName = string.Format("SELECT Class_Schedule.Section_ID, Class_Schedule.Course_ID, Class_Schedule.Days, Class_Schedule.Time, CASE WHEN Personal_Info.FirstName IS NULL THEN 'Staff' ELSE (Personal_Info.LastName + Personal_Info.FirstName) END AS Name FROM Class_Schedule JOIN Student_Enrollment ON Class_Schedule.Section_ID = Student_Enrollment.Section_ID JOIN Personal_Info ON Class_Schedule.Instructor_ID = Personal_Info.ID WHERE Student_Enrollment.Student_ID = {0}", id); SqlCommand commandFindUserInfo = new SqlCommand(sqlSelectFindUserInfoByName, connection); connection.Open(); SqlDataReader readerFindUserInfo = commandFindUserInfo.ExecuteReader(); GridView1.DataSource = readerFindUserInfo; GridView1.DataBind(); } private void clearStudentLabel() { Label1.Text = ""; Label2.Text = ""; Label3.Text = ""; Label4.Text = ""; Label5.Text = ""; } }