When you press the TAB key on an ASP.NET Web Server control, the Web page is posted back to the Web server. After the operation is complete, the focus is not set to any control. You expect the focus to be set to the next control.
This problem occurs because the AutoPostBack property of the control is set to True.
This behavior is by design.
If the AutoPostBack property is set to True, postback occurs when you press ENTER or when the control loses the focus after the contents are modified.
To work around this behavior:
In the HTML view of DEFAULT.ASPX, replace the existing code with the following:
Visual C# .NET Code
For additional information,
visit the following Microsoft Developer Network (MSDN) Web site:
This problem occurs because the AutoPostBack property of the control is set to True.
This behavior is by design.
If the AutoPostBack property is set to True, postback occurs when you press ENTER or when the control loses the focus after the contents are modified.
To work around this behavior:
- In the HTML view of WebForm1.aspx, replace the existing code with the following:
Visual C# .NET CodeVisual Basic .NET Code
<%@ Page Language="C#" AutoEventWireup="false" Codebehind="WebForm1.aspx.cs" Inherits="WebApplication11.WebForm1"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <body> <form id="Form1" method="post" runat="server"> <asp:Label id="Label1" runat="server" style="LEFT: 10px; POSITION: absolute; TOP: 20px">Label</asp:Label> <asp:textbox id="TextBox1" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 23px"></asp:textbox> <asp:Label id="Label2" runat="server" style="LEFT: 11px; POSITION: absolute; TOP: 54px">Label</asp:Label><asp:textbox id="TextBox2" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 58px"></asp:textbox> <asp:Label id="Label3" runat="server" style="LEFT: 12px; POSITION: absolute; TOP: 95px">Label</asp:Label><asp:textbox id="TextBox3" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 96px"></asp:textbox> <asp:Button id="Button1" runat="server" Text="Button" style="LEFT: 85px; POSITION: absolute; TOP: 136px"></asp:Button> <script language="javascript"> document.all["<%= Focus %>"].focus(); if("<%= ControlType %>" == "TextArea") document.all["<%= Focus %>"].select(); </script> </form> </body> </HTML>
<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm1.aspx.vb" Inherits="WebApplication11.WebForm1"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <body> <form id="Form1" method="post" runat="server"> <asp:Label id="Label1" runat="server" style="LEFT: 10px; POSITION: absolute; TOP: 20px">Label</asp:Label> <asp:textbox id="TextBox1" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 23px"></asp:textbox> <asp:Label id="Label2" runat="server" style="LEFT: 11px; POSITION: absolute; TOP: 54px">Label</asp:Label><asp:textbox id="TextBox2" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 58px"></asp:textbox> <asp:Label id="Label3" runat="server" style="LEFT: 12px; POSITION: absolute; TOP: 95px">Label</asp:Label><asp:textbox id="TextBox3" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 96px"></asp:textbox> <asp:Button id="Button1" runat="server" Text="Button" style="LEFT: 85px; POSITION: absolute; TOP: 136px"></asp:Button> <script language="javascript"> document.all["<%= Focus %>"].focus(); if("<%= ControlType %>" == "TextArea") document.all["<%= Focus %>"].select(); </script> </form> </body> </HTML> - In Solution Explorer, right-click WebForm1.aspx, and then click View Code.
- In the code-behind class, replace the existing code with the following:
Visual C# .NET CodeVisual Basic .NET Code
using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; namespace WebApplication22 { public class WebForm1 : System.Web.UI.Page { protected System.Web.UI.WebControls.Label Label1; protected System.Web.UI.WebControls.TextBox TextBox1; protected System.Web.UI.WebControls.Label Label2; protected System.Web.UI.WebControls.TextBox TextBox2; protected System.Web.UI.WebControls.Label Label3; protected System.Web.UI.WebControls.TextBox TextBox3; protected System.Web.UI.WebControls.Button Button1; protected string Focus; protected string ControlType; private void Page_Load(object sender, System.EventArgs e) { Focus = "TextBox1"; ControlType = "TextArea"; } #region Web Form Designer generated code override protected void OnInit(EventArgs e) { InitializeComponent(); base.OnInit(e); } private void InitializeComponent() { this.TextBox1.TextChanged += new System.EventHandler(this.TextBox1_TextChanged); this.TextBox2.TextChanged += new System.EventHandler(this.TextBox2_TextChanged); this.TextBox3.TextChanged += new System.EventHandler(this.TextBox3_TextChanged); this.Load += new System.EventHandler(this.Page_Load); } #endregion private void TextBox1_TextChanged(object sender, System.EventArgs e) { Focus = "TextBox2"; ControlType = "TextArea"; } private void TextBox2_TextChanged(object sender, System.EventArgs e) { Focus = "TextBox3"; ControlType = "TextArea"; } private void TextBox3_TextChanged(object sender, System.EventArgs e) { Focus = "Button1"; ControlType = "Button"; } } }
Public Class WebForm1 Inherits System.Web.UI.Page Protected WithEvents Label1 As System.Web.UI.WebControls.Label Protected WithEvents TextBox1 As System.Web.UI.WebControls.TextBox Protected WithEvents Label2 As System.Web.UI.WebControls.Label Protected WithEvents TextBox2 As System.Web.UI.WebControls.TextBox Protected WithEvents Label3 As System.Web.UI.WebControls.Label Protected WithEvents TextBox3 As System.Web.UI.WebControls.TextBox Protected WithEvents Button1 As System.Web.UI.WebControls.Button Protected Focus As String Protected ControlType As String #Region " Web Form Designer Generated Code " 'This call is required by the Web Form Designer. <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent() End Sub Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init 'CODEGEN: This method call is required by the Web Form Designer 'Do not modify it using the code editor. InitializeComponent() End Sub #End Region Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load Focus = "TextBox1" ControlType = "TextArea" End Sub Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged Focus = "TextBox2" ControlType = "TextArea" End Sub Private Sub TextBox2_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox2.TextChanged Focus = "TextBox3" ControlType = "TextArea" End Sub Private Sub TextBox3_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox3.TextChanged Focus = "Button1" ControlType = "Button" End Sub End Class - On the Build menu, click Start to view WebForm1.aspx in the browser.
- Type text in the text box, and then press the TAB key. The focus is set to the next control after the post back operation.
Back to the topSteps to Reproduce the Behavior
- Create a new ASP.NET Web Application project. By default, WebForm1.aspx is created.
- In the HTML view of WebForm1.aspx, replace the existing code with the following code:
Visual C# .NET CodeVisual Basic .NET Code
<%@ Page Language="C#" AutoEventWireup="false" Codebehind="WebForm1.aspx.cs" Inherits="WebApplication11.WebForm1"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <body> <form id="Form1" method="post" runat="server"> <asp:Label id="Label1" runat="server" style="LEFT: 10px; POSITION: absolute; TOP: 20px">Label</asp:Label> <asp:textbox id="TextBox1" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 23px"></asp:textbox> <asp:Label id="Label2" runat="server" style="LEFT: 11px; POSITION: absolute; TOP: 54px">Label</asp:Label><asp:textbox id="TextBox2" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 58px"></asp:textbox> <asp:Label id="Label3" runat="server" style="LEFT: 12px; POSITION: absolute; TOP: 95px">Label</asp:Label><asp:textbox id="TextBox3" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 96px"></asp:textbox> <asp:Button id="Button1" runat="server" Text="Button" style="LEFT: 85px; POSITION: absolute; TOP: 136px"></asp:Button> </form> </body> </HTML>
<%@ Page Language="vb" AutoEventWireup="false" Codebehind="WebForm1.aspx.vb" Inherits="WebApplication11.WebForm1"%> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <body> <form id="Form1" method="post" runat="server"> <asp:Label id="Label1" runat="server" style="LEFT: 10px; POSITION: absolute; TOP: 20px">Label</asp:Label> <asp:textbox id="TextBox1" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 23px"></asp:textbox> <asp:Label id="Label2" runat="server" style="LEFT: 11px; POSITION: absolute; TOP: 54px">Label</asp:Label><asp:textbox id="TextBox2" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 58px"></asp:textbox> <asp:Label id="Label3" runat="server" style="LEFT: 12px; POSITION: absolute; TOP: 95px">Label</asp:Label><asp:textbox id="TextBox3" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 96px"></asp:textbox> <asp:Button id="Button1" runat="server" Text="Button" style="LEFT: 85px; POSITION: absolute; TOP: 136px"></asp:Button> </form> </body> </HTML> - On the Debug menu, click Start to run the project.
SOLUTION IN ASP.NET 3.5 SP1
--------------------------------In the HTML view of DEFAULT.ASPX, replace the existing code with the following:
Visual C# .NET Code
<%@ Page Language="C#" AutoEventWireup="false" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>Untitled Page</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Label id="Label1" runat="server" style="LEFT: 10px; POSITION: absolute; TOP: 20px">Label</asp:Label>
<asp:textbox id="TextBox1" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 23px"></asp:textbox>
<asp:Label id="Label2" runat="server" style="LEFT: 11px; POSITION: absolute; TOP: 54px">Label</asp:Label>
<asp:textbox id="TextBox2" runat="server" AutoPostBack="True"
style="LEFT: 85px; POSITION: absolute; TOP: 58px"
ontextchanged="TextBox2_TextChanged1"></asp:textbox>
<asp:Label id="Label3" runat="server" style="LEFT: 12px; POSITION: absolute; TOP: 95px">Label</asp:Label><asp:textbox id="TextBox3" runat="server" AutoPostBack="True" style="LEFT: 85px; POSITION: absolute; TOP: 96px"></asp:textbox>
<asp:Button id="Button1" runat="server" Text="Button" style="LEFT: 85px; POSITION: absolute; TOP: 136px"></asp:Button>
<script language="javascript">
document.all["<%= Focus %>"].focus();
if("<%= ControlType %>" == "TextArea")
document.all["<%= Focus %>"].select();
</script>
</div>
</form>
</body>
</html>- In Solution Explorer, right-click DEFAULT.ASPX and then click View Code.
- In the code-behind class, replace the existing code with the following:
Visual C# .NET Code - using System;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
public partial class _Default : System.Web.UI.Page
{
//protected System.Web.UI.WebControls.Label Label1;
//protected System.Web.UI.WebControls.TextBox TextBox1;
//protected System.Web.UI.WebControls.Label Label2;
//protected System.Web.UI.WebControls.TextBox TextBox2;
//protected System.Web.UI.WebControls.Label Label3;
//protected System.Web.UI.WebControls.TextBox TextBox3;
//protected System.Web.UI.WebControls.Button Button1;
protected string Focus;
protected string ControlType;
private void Page_Load(object sender, System.EventArgs e)
{
// if (!IsPostBack)
// {
Focus = "TextBox1";
ControlType = "TextArea";
//}
}
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
InitializeComponent();
base.OnInit(e);
}
private void InitializeComponent()
{
this.TextBox1.TextChanged += new System.EventHandler(this.TextBox1_TextChanged);
this.TextBox2.TextChanged += new System.EventHandler(this.TextBox2_TextChanged);
this.TextBox3.TextChanged += new System.EventHandler(this.TextBox3_TextChanged);
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
private void TextBox1_TextChanged(object sender, System.EventArgs e)
{
Response.Write("abc.d.");
Focus = "TextBox2";
ControlType = "TextArea";
TextBox2.Focus();
Response.Write("abc..");
}
private void TextBox2_TextChanged(object sender, System.EventArgs e)
{
Focus = "TextBox3";
ControlType = "TextArea";
TextBox3.Focus();
}
private void TextBox3_TextChanged(object sender, System.EventArgs e)
{
Focus = "Button1";
ControlType = "Button";
Button1.Focus();
}
protected void TextBox2_TextChanged1(object sender, EventArgs e)
{
}
}
- On the Build menu, click Start to view WebForm1.aspx in the browser.
- Type text in the text box, and then press the TAB key. The focus is set to the next control after the post back operation.
visit the following Microsoft Developer Network (MSDN) Web site:
TextBox.AutoPostBack Property
http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.textbox.autopostback(vs.71).aspx (http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.textbox.autopostback(vs.71).aspx)
http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.textbox.autopostback(vs.71).aspx (http://msdn2.microsoft.com/en-us/library/system.web.ui.webcontrols.textbox.autopostback(vs.71).aspx)
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