I can't update my database when my checkbox is checked and click the Validate Button. Note:(I use Session to my pass my Data page by page)
In this another code behind page, I add a column checkbox to my gridview.
//Add a colum check row
SubjectlistTable.Columns.Add("Check", Type.GetType("System.Boolean"));
Session["ValidateSubject"] = SubjectlistTable;
Response.Redirect("ValidateSubjectTeacher.aspx");
In the ValidateSubjectTeacherPage:
This is the program Aspx:
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="ValidateSubjectTeacher.aspx.cs" Inherits="SoftwareAnalysisAndDesign.SAD.ValidateSubjectTeacher" %>
<!DOCTYPE html>
<html xmlns="http://ift.tt/lH0Osb">
<head runat="server">
<title>Student Assessment Form</title>
<meta charset="utf-8"/>
<meta name="viewport" content="width=device-width, initial-scale=1"/>
<link rel="stylesheet" href="Bootstrap/css/bootstrap-theme.css" />
<link rel="stylesheet" href="Bootstrap/css/bootstrap.min.css"/>
<link rel="stylesheet" type="text/css" href="Stylesheets/ValidateSubjectTeacherStyle.css"/>
<!--Side bar link-->
<link rel="stylesheet" href="SidebarBootstrap/css/bootstrap.min.css" />
<link rel="stylesheet" href="SidebarBootstrap/css/simple-sidebar.css" />
</head>
<body>
<form id="form1" runat="server">
<div class="headerwrapper">
<div id="headercontent" class="jumbotron">
<img id="img1" src="usjrlogo.png" />
<h1 id="title">Online AppSess System</h1>
</div>
</div>
<div class="container" style="text-align: center; margin: 0 auto;">
<br />
<h1>Validation of Subjects</h1>
<br />
<asp:GridView runat="server" CssClass="table table-hover table-bordered" ID="ValidateSubject" Style="text-align: center"></asp:GridView>
</div>
<div style="float: right; padding-right: 75px;">
<button type="button" runat="server" class="btn btn-primary" onserverclick="ValidateSubject_Click">Validate</button>
<button type="button" runat="server" class="btn btn-success" onserverclick="GoBackTeacher_Click">Go Back</button>
</div>
</form>
<script src="jquery/jquery.min.js"></script>
<script src="Bootstrap/js/bootstrap.min.js"></script>
</body>
</html>
Aspx Code Behind:
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;
using System.Data;
namespace SoftwareAnalysisAndDesign.SAD
{
public partial class ValidateSubjectTeacher : System.Web.UI.Page
{
CheckBox check = new CheckBox();
protected void Page_Load(object sender, EventArgs e)
{
if (Session["ValidateSubject"] == null)
{
Response.Redirect("TeacherPage.aspx", true);
}
if (!IsPostBack)
{
ValidateSubject.DataSource = Session["ValidateSubject"];
ValidateSubject.DataBind();
}
//Add a checkbox in the last row of GridView Progmatically
foreach (GridViewRow row in ValidateSubject.Rows)
{
check = row.Cells[row.Cells.Count - 1].Controls[0] as CheckBox; //position Check column on last row in gridview
check.Enabled = true;
check.CheckedChanged += ValidateSubject_Click; //Bind the event on the button
check.AutoPostBack = true; //Set the AutoPostBack property to true
}
}
protected void ValidateSubject_Click(object sender, EventArgs e)
{
CheckBox chk = (CheckBox)sender;
GridViewRow grvRow = (GridViewRow)chk.NamingContainer;//This will give row
string validated = "Validated";
string notyetvalidated = "Not yet validated";
string studid = grvRow.Cells[0].Text;
string coursenum = grvRow.Cells[1].Text;
if (chk.Checked)
{
grvRow.Cells[10].Text = validated;
//Open Connection
using (SqlConnection conn = new SqlConnection("Data Source=Keith;Initial Catalog=SAD;Integrated Security=True"))
{
//Open Connection to database
try
{
conn.Open();
}
catch (Exception E)
{
Console.WriteLine(E.ToString());
}
using (SqlCommand cmd = new SqlCommand("Update AssessmentForm set Status = @Validated where StudentID = @studentID and CourseNo = @Coursenumber" ,conn))
{
cmd.Parameters.AddWithValue("@Validated", validated);
cmd.Parameters.AddWithValue("@studentID", studid);
cmd.Parameters.AddWithValue("@Coursenumber", coursenum);
cmd.ExecuteNonQuery();
}
//Close Connection to database
try
{
conn.Close();
}
catch (Exception E)
{
Console.WriteLine(E.ToString());
}
}
}
else
{
grvRow.Cells[10].Text = notyetvalidated;
}
}
protected void GoBackTeacher_Click(object sender, EventArgs e)
{
Response.Redirect("TeacherPage.aspx");
}
}
}
The code is working but when I click the submit button, the system prompts me with an error and I can't update my database:
Error message:
An exception of type 'System.InvalidCastException' occurred in SoftwareAnalysisAndDesign.dll but was not handled in user code Additional information: Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlButton' to type 'System.Web.UI.WebControls.CheckBox'.
There's something wrong with my checkbox event here:
CheckBox chk = (CheckBox)sender;
It seems that checkbox event and button event can't be simultaneously handled. Please help, this is the only problem I want to fix so that my System is fully working.
Related link Get specific data and update database
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