Question

<%@ Page Title="Log In" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeBehind="Login.aspx.cs" Inherits="EQ.Account.Login" %>
<asp:Content ID="HeaderContent" runat="server" ContentPlaceHolderID="HeadContent">
</asp:Content>
<asp:Content ID="BodyContent" runat="server" ContentPlaceHolderID="MainContent">
<h2>
    Log In
</h2>
<p>
    Please enter your Employee Code and password.
    If you don't have an account Please Contact your Manager.
</p>
<asp:Login ID="LoginUser" runat="server" EnableViewState="false" RenderOuterTable="false">
    <LayoutTemplate>
        <span class="failureNotification">
            <asp:Literal ID="FailureText" runat="server"></asp:Literal>
        </span>
        <asp:ValidationSummary ID="LoginUserValidationSummary" runat="server" CssClass="failureNotification" 
             ValidationGroup="LoginUserValidationGroup"/>
        <div class="accountInfo">
            <fieldset class="login">
                <legend>Account Information</legend>
                <p>
                    <asp:Label ID="UserNameLabel" runat="server" AssociatedControlID="UserName">Username:</asp:Label>
                    <asp:TextBox ID="txtUserName" runat="server" CssClass="textEntry"></asp:TextBox>
                    <asp:RequiredFieldValidator ID="UserNameRequired" runat="server" ControlToValidate="UserName" 
                         CssClass="failureNotification" ErrorMessage="User Name is required." ToolTip="User Name is required." 
                         ValidationGroup="LoginUserValidationGroup">*</asp:RequiredFieldValidator>
                </p>
                <p>
                    <asp:Label ID="PasswordLabel" runat="server" AssociatedControlID="Password">Password:</asp:Label>
                    <asp:TextBox ID="txtPassword" runat="server" CssClass="passwordEntry" TextMode="Password"></asp:TextBox>
                    <asp:RequiredFieldValidator ID="PasswordRequired" runat="server" ControlToValidate="Password" 
                         CssClass="failureNotification" ErrorMessage="Password is required." ToolTip="Password is required." 
                         ValidationGroup="LoginUserValidationGroup">*</asp:RequiredFieldValidator>
                </p>
                <p>
                    <asp:CheckBox ID="RememberMe" runat="server"/>
                    <asp:Label ID="RememberMeLabel" runat="server" AssociatedControlID="RememberMe" CssClass="inline">Keep me logged in</asp:Label>
                </p>
                <p>
                <asp:Label ID="lblErrorMessage" runat="server" CssClass="failureNotification" Visible="false" />
                </p>
            </fieldset>
            <p class="submitButton">
                <asp:Button ID="LoginButton" runat="server" CommandName="Login" Text="Log In" ValidationGroup="LoginUserValidationGroup" OnClick="LoginButton_Click"/>
            </p>
        </div>
    </LayoutTemplate>
</asp:Login>

This is my ASP page but in the CodeBehind page i.e. Login.aspx.cs, when i m trying to get the values of the controls like lblErrorMessage,txtuserName and txtPassword , i m getting error that “Error 1 The name ‘txtUserName’ does not exist in the current context C:\Users\dsingh\Documents\Visual Studio 2010\Projects\EQ\EQ\Account\Login.aspx.cs 64 46 EQ
“.
Waiting if some one will solve this problem and guide me that why it is not recognizing the controls from the code behind.

Answer 1

To access the UserName text box you will have traverse the object tree using the FindControl method. E.G.,

string myValue = (LoginUser.FindControl("UserName") as TextBox).Text;

To make life a bit easier and the code more readable you can add an extension method to return strongly typed controls.

// usage
var myControlUsingExtensionMethod = LoginUser.FindControl<TextBox>("UserName").Text;

public static class ControlExtensions
{
    public static T FindControl<T>(this Control control, string id) where T : Control
    {
        return control.FindControl(id) as T;
    }
}