无法找到控件（DropDownlist）
问题描述：
<table class="auto-style1" id="table1" runat="server" visible="false">
<tr id="row1" visible="false">
<td id="grade1" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs1" runat="server"><asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row2" visible="false">
<td id="grade2" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList3" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs2" runat="server"><asp:DropDownList ID="DropDownList4" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row3" visible="false">
<td id="grade3" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList5" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs3" runat="server"><asp:DropDownList ID="DropDownList6" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row4" visible="false">
<td id="grade4" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList7" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs4" runat="server"><asp:DropDownList ID="DropDownList8" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row5" visible="false">
<td id="grade5" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList9" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs5" runat="server"><asp:DropDownList ID="DropDownList10" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row6" visible="false">
<td id="grade6" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList11" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs6" runat="server"><asp:DropDownList ID="DropDownList12" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row7" visible="false">
<td id="grade7" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList13" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs7" runat="server"><asp:DropDownList ID="DropDownList14" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row8" visible="false">
<td id="grade8" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList15" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs8" runat="server"><asp:DropDownList ID="DropDownList16" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row9" visible="false">
<td id="grade9" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList17" runat="server" DataSourceID="SqlDataSource1" DataTextField="grade" DataValueField="grade"></asp:DropDownList></td>
<td id="hrs9" runat="server"><asp:DropDownList ID="DropDownList18" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="row10" visible="false">
<td id="grade10" runat="server" class="auto-style3"><asp:DropDownList ID="DropDownList19" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
<td id="hrs10" runat="server"><asp:DropDownList ID="DropDownList20" runat="server" DataSourceID="SqlDataSource2" DataTextField="hours" DataValueField="hours"></asp:DropDownList></td>
</tr>
<tr id="submitrow" runat="server">
<td class="auto-style3"><asp:Button CssClass="submit" ID="Button2" runat="server" Text="Submit" OnClick="Button2_Click" /></td>
</tr>
</table>//to calculate the average of marks
protected void Button2_Click(object sender, EventArgs e)
{
int num=Convert.ToInt32(Session["courses"]);
for (int i = 1; i <=num ; i++)
{
DropDownList dd = (DropDownList)Page.FindControl("DropDownList" + i);
string drpDLstVal = dd.SelectedValue.ToString();
if (i % 2 == 0)
{
hrs += Convert.ToDouble(drpDLstVal);
}
else
{
grade += value(drpDLstVal);
}
}
double avg = grade / hrs;
Label1.Visible = true;
Label1.Text = avg.ToString();
}
public double value(string grade)
{
switch (grade)
{
case "A":
mark = 4;
break;
case "B+":
mark = 3.5;
break;
case "B":
mark = 3;
break;
case "C+":
mark = 2.5;
break;
case "C":
mark = 2;
break;
case "D+":
mark = 1.5;
break;
case "D":
mark = 1;
break;
case "F":
mark = .5;
break;
}
return mark;
}
I can’’t get the drop down list to send it
答
I hope this help:
I hope this help:
DropDownList dd = this.Master.FindControl("DropDownList" + i) as DropDownList;
Update:
This is a simple project that works without any problem:
Update:
This is a simple project that works without any problem:
<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site.master.cs" Inherits="WebApplication1.SiteMaster" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head runat="server">
<title></title>
</head>
<body>
<form runat="server">
<asp:DropDownList ID="DropDownList1" runat="server">
<asp:ListItem Text="1" Value="1" />
<asp:ListItem Text="2" Value="2" />
<asp:ListItem Text="3" Value="3" />
<asp:ListItem Text="4" Value="4" />
</asp:DropDownList>
<asp:Button ID="Button1" runat="server"
Text="Button" OnClick="Button1_Click1" />
<asp:Label ID="Label1" runat="server" Text="MasterLabel"></asp:Label>
<asp:ContentPlaceHolder ID="MainContent" runat="server">
</asp:ContentPlaceHolder>
</form>
</body>
</html>using System;
using System.Web;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class SiteMaster : System.Web.UI.MasterPage
{
protected void Button1_Click1(object sender, EventArgs e)
{
DropDownList dd = (DropDownList)FindControl("DropDownList"+1);
string drpDLstVal = dd.SelectedValue.ToString();
Label1.Visible = true;
Label1.Text = drpDLstVal;
}
}
}<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click1" />
<asp:Label ID="Label2" runat="server" Text="PageLabel"></asp:Label>
</asp:Content>using System;
using System.Web;
using System.Web.UI.WebControls;
namespace WebApplication1
{
public partial class _Default : System.Web.UI.Page
{
protected void Button1_Click1(object sender, EventArgs e)
{
DropDownList dd = (DropDownList)Master.FindControl("DropDownList"+1);
string drpDLstVal = dd.SelectedValue.ToString();
Label2.Visible = true;
Label2.Text = drpDLstVal;
}
}
}content = (ContentPlaceHolder)Master.FindControl("ContentPlaceHolder1");
if (content != null)
{
dd = (DropDownList)content.FindControl("DropDownList" + i);