在我正在处理的项目中，我的一些动态复选框有问题。
我有一个表格，在每行一个单元格中，我有一个复选框。选中此复选框以“标记”该记录。在用户设置了一系列过滤器后，单击按钮即可填充表中的记录。因此，表内容在每次回发时都会完全改变。
我使用一个列表来保存哪些记录已被标记，这样如果出现以前检查过的记录，也会在该检索时检查它。
我正在对我的page_load函数中的列表执行此检查，我可以通过调试看到它设置正确。但是，当页面加载完成时，检查的状态通常是错误的。
我是否需要将复选框状态验证步骤移至页面生命周期的另一部分？
任何提示都会很棒。我发现了一些关于带有复选框的 asp.net 问题的问题，但它们似乎与我的问题无关。
这是代码，请随时批评任何/全部:)
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace ScienceAssessmentToolASP
{
public partial class createnewtest : System.Web.UI.Page
{
private int n;
private SqlConnection conn = null;
private List<int> flaggedQuestions = new List<int>();
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
var temp = (List<int>)Session["flaggedQuestions"];
if (temp != null)
flaggedQuestions = temp; ;//retrieve flags from session
try
{
GetConn();
ExecuteRetrieval();
n = 1;
}
catch (Exception ex) { n = 0; Response.Write("for debugging: " + ex); }
finally { if (conn != null) conn.Close(); }
if (n < 0)
//Label1.Text = "Connection Successful";
Label3.Text = "Failed to Connect to Database, please contact the administrator.";
}
}
protected void Button1_Click(object sender, EventArgs e)
{
}
private void GetConn()
{
string connString = @"laalalala";
conn = new SqlConnection(connString);
conn.Open();
}
private void ExecuteRetrieval()
{
SqlDataReader reader = null;
string query;
if (!IsPostBack)
{
query = "select * from [ScienceQA]";
flaggedQuestions = (List<int>)Session["flaggedQuestions"];//retrieve flags from session
}
else query = "select * from [ScienceQA] where [GradeLevel] = " + DropDownList1.Text +
" and [Topic] = '" + DropDownList2.Text + "';";
SqlCommand cmd = new SqlCommand(query, conn);
reader = cmd.ExecuteReader();
TableHeaderRow headerRow = new TableHeaderRow();
TableHeaderCell idH = new TableHeaderCell();
TableHeaderCell questionH = new TableHeaderCell();
TableHeaderCell answerH = new TableHeaderCell();
TableHeaderCell flagH = new TableHeaderCell();
idH.Text = "ID";
questionH.Text = "Question";
answerH.Text = "Answer";
flagH.Text = "Flag";
headerRow.Cells.Add(idH);
headerRow.Cells.Add(questionH);
headerRow.Cells.Add(answerH);
headerRow.Cells.Add(flagH);
resultTable.Controls.Add(headerRow);
while (reader.Read())
{
TableRow row = new TableRow();
TableCell idCell = new TableCell();
TableCell qCell = new TableCell();
TableCell aCell = new TableCell();
TableCell flag = new TableCell();
idCell.Text = reader[0].ToString();
qCell.Text = reader[1].ToString();
aCell.Text = reader[2].ToString();
CheckBox flagBox = new CheckBox();
int id = Convert.ToInt32(idCell.Text);
flagBox.AutoPostBack = true;
flagBox.CheckedChanged += new System.EventHandler(flagButton_Click);
flagBox.EnableViewState = true;
flagBox.ViewStateMode = ViewStateMode.Enabled;
if (flaggedQuestions.Contains(id) && flagBox.ID == "flag" + id)
flagBox.Checked = true;
else flagBox.Checked = false;
flagBox.Text = id.ToString();
flag.Controls.Add(flagBox);
row.Cells.Add(idCell);
row.Cells.Add(qCell);
row.Cells.Add(aCell);
row.Cells.Add(flag);
resultTable.Controls.Add(row);
}
Label4.Visible = true;
flagCounter.Visible = true;
resultTable.Visible = true;
}
protected void flagButton_Click(object sender, EventArgs e)
{
CheckBox lb = (CheckBox)sender;
int questionID = Convert.ToInt32(lb.ID.Substring(4));
if (lb.Checked && !flaggedQuestions.Contains(questionID))
{
//lb.Checked = false;
flaggedQuestions.Add(questionID);
flagCounter.Text = Convert.ToString(flaggedQuestions.Count);
}
else
{
//lb.Checked = true;
flaggedQuestions.Remove(questionID);
flagCounter.Text = Convert.ToString(flaggedQuestions.Count);
}
Session["flaggedQuestions"] = flaggedQuestions;//store questions to session
}
protected void createTestButton_Click(object sender, EventArgs e)
{
//create a test
bool sendQuery = true;
string author = Session["user"].ToString();
string accessLevel = accessDropdown.Text;
int gradeLevel = Convert.ToInt32(DropDownList1.Text);
int questionCount = flaggedQuestions.Count();
string testType = testTypeDropDown.Text;
string description = descriptionBox.Text;
string questionString = "";
for (int i = 0; i < flaggedQuestions.Count(); i++)
questionString += flaggedQuestions[i] + ",";
string query = @"Insert into Tests Values ('" + author + "','" + questionString
+ "','" + accessLevel + "','" + gradeLevel + "','" + questionCount + "','"
+ testType + "','" + description +"');";
//check parameters
if (accessLevel == "")
{
errorLabel.Text = "Please choose an access level.";
sendQuery = false;
}
if (questionCount == 0)
{
errorLabel.Text = "Please flag a set of questions before creating a test.";
sendQuery = false;
}
if (testType == "")
{
errorLabel.Text = "Please choose a test type";
sendQuery = false;
}
if (description == "")
{
errorLabel.Text = "Please describe your test";
sendQuery = false;
}
if (sendQuery)
{
try
{
GetConn();
SqlCommand cmd = new SqlCommand(query, conn);
cmd.Prepare();
int n;
n = cmd.ExecuteNonQuery();
}
catch (Exception e2) { n = 0; }
if (n == 1)
errorLabel.Text = "Test Created Successfully";
else errorLabel.Text = "Test Creation Failed, please check your parameters.";
}
}
}
}
这是对我有用的解决方案，将复选框状态检查移至 onprerender 函数。
protected override void OnPreRender(EventArgs e)
{
foreach (TableRow row in resultTable.Rows)
{
var cell = row.Cells[3];
foreach (Control control in cell.Controls)
{
var flagBox = control as CheckBox;
if (flagBox != null)
{
int id = Convert.ToInt32(flagBox.ID.Substring(4));
if (flaggedQuestions.Contains(id) && flagBox.ID == "flag" + id)
flagBox.Checked = true;
else flagBox.Checked = false;
}
}
}
}