问题：事件处理程序quantity_TextChanged不会更改会话变量"list"以反映当前状态。事件处理程序附加到addItemRowToTable生成的所有文本框，并通过分配的id将它们区分开来。
我肯定有什么东西不见了，但我不确定。
附加信息：我需要这样做，即对多个文本框所做的更改都保存到一个Session变量中，以便以后在会话中进一步使用，顺序与表中显示的顺序相同。然后，每个文本框中的值将用于其旁边的标签(每个文本框1个标签(。
期望结果：
Header Header2
[TextBox with value of 42] [Label displaying 42]
[TextBox with value of 76] [Label displaying 76]
[TextBox with value of 105] [Label displaying 105]
WebForm1.aspx.cs
protected void Page_LoadComplete(object sender, EventArgs e)
{
if (Session["list"] != null)
{
List<int> numbers = Session["list"] as List<int>;
int index = 0;
foreach (int item in numbers)
{
tblItems.Rows.AddAt(index + 1, addItemRowToTable(item, index));
// For debugging purposes
Response.Write("<script>console.log("" + item.ToString() + "");</script>");
index++;
}
}
}
private TableRow addItemRowToTable(int item, int index)
{
TableCell[] cells = { new TableCell(), new TableCell() };
TableRow row = new TableRow();
TextBox box = new TextBox();
box.ID = String.Format("{0}_q", index);
box.Attributes["type"] = "number";
box.Attributes["min"] = "1";
box.Attributes["width"] = "60px";
box.TextChanged += new EventHandler(quantity_TextChanged);
box.AutoPostBack = true;
cells[0].Controls.Add(box);
Label lbl = new Label();
lbl.ID = String.Format("{0}_l", index);
lbl.Text = item.ToString();
cells[1].Controls.Add(lbl);
foreach (TableCell cell in cells)
row.Cells.Add(cell);
return row;
}
protected void Button1_Click(object sender, EventArgs e)
{
if (Session["list"] != null)
{
List<int> numbers = Session["list"] as List<int>;
numbers.Add(0);
Session["list"] = numbers;
}
else
{
List<int> numbers = new List<int>();
numbers.Add(0);
Session["list"] = numbers;
}
}
private void quantity_TextChanged(object sender, EventArgs e)
{
if (Session["list"] != null)
{
TextBox item = sender as TextBox;
int position = Convert.ToInt32(item.ID.Split('_')[0]);
List<int> numbers = Session["list"] as List<int>;
numbers[position] = Convert.ToInt32(item.Text);
Session["list"] = numbers;
}
}
WebForm1.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Assignment2.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
<br />
<br />
<asp:Table ID="tblItems" runat="server">
<asp:TableHeaderRow>
<asp:TableHeaderCell>Header</asp:TableHeaderCell>
<asp:TableHeaderCell>Header2</asp:TableHeaderCell>
</asp:TableHeaderRow>
</asp:Table>
</div>
</form>
</body>
</html>
首先，您不需要在Page_LoadComplete中。我认为，这可能是你试图在点击按钮后添加正确数量的文本框。但是单击按钮应该只添加一个新的TextBox，仅此而已。在Page_Load中，您需要添加存储在会话中的文本框。请参阅下面的示例，以获取具有TextChanged事件的有效解决方案，该事件之所以有效，是因为所有正确的控件都在回发时重新创建。
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack == false)
{
//do not add or manipulate dynamic controls inside an ispostback check
}
//check if the session exists
if (Session["list"] != null)
{
//add the correct number of textboxes from session
for (int i = 1; i <= Convert.ToInt32(Session["list"]); i++)
{
addTextBox(i);
}
}
}
private void addTextBox(int index)
{
//create a new textbox
TextBox tb = new TextBox();
tb.ID = "DynamicTextBox" + index;
tb.AutoPostBack = true;
//add an event to the textbox
tb.TextChanged += new EventHandler(quantity_TextChanged);
//add the textbox to the page
PlaceHolder1.Controls.Add(tb);
}
protected void Button1_Click(object sender, EventArgs e)
{
int index = 1;
//get the current textbox count if it exists
if (Session["list"] != null)
{
index = Convert.ToInt32(Session["list"]) + 1;
}
//add a new textbox
addTextBox(index);
//upate the session with the new value
Session["list"] = index;
}
private void quantity_TextChanged(object sender, EventArgs e)
{
//display the textbox value in a label for testing
Label1.Text = ((TextBox)sender).Text;
}