When finding a control that caused the postback, <asp:ImageButton> & <asp:Button> are exceptions as they do not use __doPostBack function. This fact is also supported by this Article.
So, as the article pointed above uses a hiddenField, Javascript codes for workaround, Is there a more elegant way of doing this??
What I want is when using a Button/ImageButton control, i still want to use Request.Form["__EVENTTARGET"] to somehow get the control name. Is there any setting that i need to know??
OR
Any property of Button / ImageButton that will make it use the __doPostBack function ??
Below is code I was trying ::
EventTargets.aspx
<%# Page Title="" Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true"
CodeFile="EventTargets.aspx.cs" Inherits="EventTargets" %>
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" Runat="Server">
<asp:Button ID="btnAdd" runat="server" Text="Add"
ClientIDMode="Static"/>
</asp:Content>
And the complete code of my cs file:
EventTargets.aspx.cs
public partial class EventTargets: System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
string CtrlID = string.Empty;
// for Button Controls, this is always string.Empty
// and therefore it doesn't goes inside IF statement
if (Request.Form["__EVENTTARGET"] != null &&
Request.Form["__EVENTTARGET"] != string.Empty)
{
CtrlID = Request.Form["__EVENTTARGET"];
}
}
}
}
I don't know its ELEGANT WAY for you or not :) but it is easy..see..
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack)
{
Control c = GetPostBackControl(this.Page);
string ctrlId = c.ID;
}
}
private Control GetPostBackControl(Page page)
{
Control control = null;
string postBackControlName = Request.Params.Get("__EVENTTARGET");
string eventArgument = Request.Params.Get("__EVENTARGUMENT");
if (postBackControlName != null && postBackControlName.Length > 0)
{
control = Page.FindControl(postBackControlName);
}
else
{
foreach (string str in Request.Form)
{
Control c = Page.FindControl(str);
if (c is Button)
{
control = c;
break;
}
}
}
return control;
}
Related
I am a using ASP.NET controller to display user detail. When RadWindow is open & I tried to close with Close button. But the problem is that after page load and post back it opens again and again. I've multi-option on page: new, save, print etc. search.
<telerik:RadWindow ID="rwReport" runat="server" Behaviors="Close" KeepInScreenBounds="true"
AutoSize="true" VisibleOnPageLoad="false" Modal="true" Title="Report ACMI Advance Payment"
DestroyOnClose="true">
<ContentTemplate>
<ucRPV:ReportViewer id="ucReportViewer" runat="server" />
</ContentTemplate>
</telerik:RadWindow>
cs file code
private void Print()
{
try
{
// this.sADPs.DisplayReport();
Hashtable reportParameters = new Hashtable();
reportParameters.Add("DataSourceName", "dsACMIAdvancePayment");
reportParameters.Add("reportName", "rptACMIAdvancePayment.rdlc");
reportParameters.Add("Id", this.hfId.Value.ToString().ConvertTo<long>());
this.ucReportViewer.clearReport();
this.ucReportViewer.showReport(reportParameters);
this.rwReport.VisibleOnPageLoad = true;
//showReport(reportParameters);
}
catch(Exception e)
{
throw e;
}
}
ASPX code:
<%# Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="AjaxControlToolkit" %>
<%# Register Src="../Reports/rpvReportViewerPopup.ascx" TagName="ReportViewer" TagPrefix="ucRPV" %>
<%# Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %>
<%# Register Src="../Common/UserControls/ToolBarActions.ascx" TagName="ToolBarActions" TagPrefix="ucTBA" %>
</td>
Do not use the VisibleOnPageLoad property to show a RadWindow, register a script that will call its show() method. Thus, subsequent postbacks will not cause it to show up by itself: http://www.telerik.com/help/aspnet-ajax/window-troubleshooting-opening-from-server.html.
Of course, preventing the form from re-submitting as Felice suggested is another thing that may also be needed.
To translate this into code:
instead of:
this.rwReport.VisibleOnPageLoad = true;
use:
string script = "function f(){$find(\"" + rwReport.ClientID + "\").show(); Sys.Application.remove_load(f);}Sys.Application.add_load(f);";
ScriptManager.RegisterStartupScript(Page, Page.GetType(), "key", script, true);
You can try below code : this might help-
<telerik:RadScriptBlock runat="server" ID="scriptBlock">
<script type="text/javascript">
//<![CDATA[
function GetRadWindow() {
var oWindow = null;
if (window.radWindow) oWindow = window.radWindow;
else if (window.frameElement.radWindow) oWindow = window.frameElement.radWindow;
return oWindow;
}
function CloseWin() {
//Get the RadWindow
var oWindow = GetRadWindow();
//Call its Close() method
if (oWindow) {
oWindow.Close();
}
return false;
}
</script>
</telerik:RadScriptBlock>
And on Page: yourpage.aspx;... call the function onClientClick of button:
<asp:Button ID="btnClose" Text="Close" runat="server" CssClass="button" Enabled="true" OnClientClick="CloseWin();" />
I have experienced the same problem when you reload the page because the browser resend the information and the radwindow opens again. To avoid such behavior I have adopted the following solution:
Add a hidden filed to hold the client code:
<asp:HiddenField runat="server" ID="_repostcheckcode" />
Add the following code in the code page:
protected void Page_Load(object sender, EventArgs e)
{
CancelUnexpectedRePost();
}
private void CancelUnexpectedRePost()
{
string clientCode = _repostcheckcode.Value;
//Get Server Code from session (Or Empty if null)
string serverCode = Session["_repostcheckcode"] as string ?? "";
if (!IsPostBack || clientCode.Equals(serverCode))
{
//Codes are equals - The action was initiated by the user
//Save new code (Can use simple counter instead Guid)
string code = Guid.NewGuid().ToString();
_repostcheckcode.Value = code;
Session["_repostcheckcode"] = code;
}
else
{
//Unexpected action - caused by F5 (Refresh) button
Response.Redirect(Request.Url.AbsoluteUri);
}
}
The original article can be found here.
Add a Button with an OnClick handler with the following code:
protected void CloseRadWindow(object sender, EventArgs e)
{
rwReport.VisibleOnPageLoad = false;
}
I made a simple control with 1 text box.
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="sTextBox.ascx.cs" Inherits="TestingASPNET.Controls.sTextBox" className="sTextBox"%>
<asp:Textbox runat="server" ID="tbNothing"/>
<br />
I call this control as a reference in my default.aspx Here's the simple code.
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="default.aspx.cs" Inherits="TestingASPNET._default" %>
<%# Reference Control="~/Controls/sTextBox.ascx"%>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:PlaceHolder runat="server" id="PlaceHolder1" />
</div>
</form>
</body>
</html>
In my code behind in default.aspx.cs I have.
protected void Page_Load(object sender, EventArgs e)
{
PlaceHolder1.Controls.Add(LoadControl("~/Controls/sTextBox.ascx"));
PlaceHolder1.Controls.Add(LoadControl("~/Controls/sTextBox.ascx"));
}
This adds the 2 sTextBox onto my page.
The problem I'm having is how to I use the control like I would a normal textBox. For example.
TextBox tb = new TextBox();
tb.Text = "textbox";
PlaceHolder1.Controls.Add(tb);
This adds a text box on the page with the text "textbox" in it.
Can Someone give me a way to do EXACTLY this, but with the control sTextBox.
you can get that behavior by adding properties to your custom control.
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
var ctrl = (sTextBox) Page.LoadControl("~/sTextBox.ascx");
ctrl.Text = "something";
placeHolder1.Controls.Add(ctrl);
}
}
User Control :-
public partial class sTextBox : System.Web.UI.UserControl
{
public string Text { get; set; }
}
I couldn't get your code to work.
I either had to
var ctrl = (ProjectName.Controls.sTextBox) Page.LoadControl("~/Controls/sTextBox.ascx");
or import the control
using ProjectName.Controls;
When I did this, it worked.
Also your get set property wasn't work either, I had to change it to.
public string Text {
get
{
return tbNothing.Text;
}
set
{
tbNothing.Text = value;
}
}
Afterwards I added 1 more textbox into the control totaling 2. I changed the ID to tb1Text and tb2Text. I then had to get 2 methods for my get sets, which was
public string tb1Text {
get
{
return tb1.Text;
}
set
{
tb1.Text = value;
}
}
public string tb2Text
{
get
{
return tb2.Text;
}
set
{
tb2.Text = value;
}
}
inside my default code behind, I had to use
sTextBox ctrl = (sTextBox)Page.LoadControl("~/Controls/sTextBox.ascx");
ctrl.tb1Text = "something";
ctrl.tb2Text = "something 2";
PlaceHolder1.Controls.Add(ctrl);
This worked, now I know how to use 2 textboxes on 1 control :) . Hopefully it's the same with other controls that I have to make :S
My code generates an TextBox on the fly in C# (page_load function). Can I access it in the code later? It does give me compilation error and does not seem to work. Can someone verify ?
Code for additonal problem
aContent += "<table>";
aContent += "<tr><td>lablel </td><td style='bla blah'><input type='textbox' id='col-1' name='col-1'/></td></tr> ... 10 such rows here
</table>"
spanMap.InnerHtml = aContent;
The contents are rendered OK but recusrive iteration does not return the textbox. I am calling it like this
TextBox txt = (TextBox)this.FindControlRecursive(spanMap, "col-1");
// txt = (TextBox) spanMapping.FindControl("col-1"); this does not work too
if (txt != null)
{
txt.Text = "A";
}
Assuming that you're persisting it correctly, you should be able to access it in code-behind using the FindControl method. Depending on where the control is, you may have to search recursively through the control hierarchy:
private Control FindControlRecursive(Control root, string id)
{
if (root.ID == id)
{
return root;
}
foreach (Control c in root.Controls)
{
Control t = FindControlRecursive(c, id);
if (t != null)
{
return t;
}
}
return null;
}
Using FindControlRecursive:
TextBox txt = this.FindControlRecursive(Page.Form, "TextBox1") as TextBox;
if (txt != null)
{
string text = txt.Text;
}
If you still can't find it using the above method, make sure that you're creating the control during after every postback, somwhere before Page_Load, like OnInit.
EDIT
I think you need to change the way you're adding content to the container. Instead of using a <span>, I would use a Panel, and instead of building markup, simply add controls to the panel in code-behind:
TextBox txt = new TextBox();
txt.ID = String.Format("txt_{0}", Panel1.Controls.Count);
Panel1.Controls.Add(txt);
Here's an example:
<%# Page Language="C#" %>
<script type="text/C#" runat="server">
protected void Page_Load(object sender, EventArgs e)
{
var textBox = new TextBox();
textBox.ID = "myTextBox";
textBox.Text = "hello";
Form1.Controls.Add(textBox);
}
protected void BtnTestClick(object sender, EventArgs e)
{
var textBox = (TextBox)Form1.FindControl("myTextBox");
lblTest.Text = textBox.Text;
}
</script>
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<form id="Form1" runat="server">
<asp:LinkButton ID="btnTest" runat="server" Text="Click me" OnClick="BtnTestClick" />
<asp:Label ID="lblTest" runat="server" />
</form>
</body>
</html>
Basically, in a nutshell, the problem is that dynamically generated triggers for an UpdatePanel can no longer be found (by ASP.NET) as soon as I add them as children of a custom control.
Since the amount of code I'm working on is quite substantial I've recreated the problem on a smaller scale, which will make it easier to debug.
The error thrown in my face is:
A control with ID 'theTrigger' could not be found for the trigger in UpdatePanel 'updatePanel'.
I'm not sure whether this implementation of a "custom control" is the right way to go about it, but I did not write the original implementation: I'm working with code written by a previous developer to which I cannot make large modifications. It looks a little unusual to me, but, alas, this is what I've been given.
Default.aspx
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="TestWeb.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></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:Panel runat="server" ID="panel">
</asp:Panel>
<asp:ScriptManager ID="scriptManager" runat="server"></asp:ScriptManager>
<asp:UpdatePanel runat="server" ID="updatePanel" UpdateMode="Conditional">
<ContentTemplate>
<asp:Label ID="lblSomething" runat="server"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>
</body>
</html>
Default.aspx.cs
using System;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace TestWeb
{
public partial class Default : Page
{
protected void Page_Load(object sender, EventArgs e)
{
UselessTableWrapper table = new UselessTableWrapper();
TableRow tr = new TableRow();
TableCell td = new TableCell();
LinkButton button1 = new LinkButton { ID = "theTrigger", Text = "Click Me" };
button1.Click += button1_Click;
td.Controls.Add(button1);
tr.Controls.Add(td);
table.AddRow(tr);
panel.Controls.Add(table);
// ### uncomment these lines (and comment the one above) to see it working
// ### without the custom control
/*
Table realTable = new Table();
realTable.Controls.Add(tr);
panel.Controls.Add(realTable);
*/
updatePanel.Triggers.Add(new AsyncPostBackTrigger { ControlID = "theTrigger", EventName = "Click" });
scriptManager.RegisterAsyncPostBackControl(button1);
}
protected void button1_Click(object sender, EventArgs e)
{
lblSomething.Text = "Random number: " + new Random().Next(100);
updatePanel.Update();
}
}
}
MyControl.cs
using System;
using System.Web.UI.WebControls;
namespace TestWeb
{
public class UselessTableWrapper : WebControl
{
private Table table = new Table();
protected override void OnPreRender(EventArgs e)
{
Controls.Add(table);
}
public void AddRow(TableRow row)
{
table.Controls.Add(row);
}
}
}
Any ideas would be greatly appreciated.
Edit
I've tried switching the OnPreRender event for this (found in a tutorial):
protected override void RenderContents(HtmlTextWriter writer)
{
writer.BeginRender();
table.RenderControl(writer);
writer.EndRender();
base.RenderContents(writer);
}
... hoping that it would fix it, but it does not.
this is the approach that I've taken with loading a ascx web control inside an aspx control from the code behind.
In the control:
namespace dk_admin_site.Calculations
{
public partial class AssignedFieldCalculation : System.Web.UI.UserControl
{
public static AssignedFieldCalculation LoadControl(Calculation initialData)
{
var myControl = (AssignedFieldCalculation) ((Page) HttpContext.Current.Handler).LoadControl(#"~\\Calculations\AssignedFieldCalculation.ascx");
myControl._initialData = initialData;
return myControl;
}
private Calculation _initialData;
public Calculation Data { get { return _initialData; } }
protected void Page_Load(object sender, EventArgs e) {}
}
}
in the web form code behind:
protected void Page_Load(object sender, EventArgs e)
{
if (this.IsPostBack)
{
if (ScriptManager1.AsyncPostBackSourceElementID.StartsWith("ctl00$MainContent$calc") && ScriptManager1.AsyncPostBackSourceElementID.EndsWith("$btnRemoveCalculationFromField"))
{
//do something on the postback
}
else if (ScriptManager1.AsyncPostBackSourceElementID.StartsWith("ctl00$MainContent$calc") && (ScriptManager1.AsyncPostBackSourceElementID.EndsWith("$btnMoveCalculationUp") || ScriptManager1.AsyncPostBackSourceElementID.EndsWith("$btnMoveCalculationDown")))
{
//do something on the postback
}
}
foreach (Calculation calc in calculationCollection)
{
AssignedFieldCalculation asCalc = AssignedFieldCalculation.LoadControl(calc);
asCalc.ID = "calc" + calc.UniqueXKey;
pnlFieldCalculations.Controls.Add(asCalc);
foreach (Control ct in asCalc.Controls)
{
if (ct.ID == "btnMoveCalculationDown" || ct.ID == "btnMoveCalculationUp" || ct.ID == "btnRemoveCalculationFromField")
{
ScriptManager1.RegisterAsyncPostBackControl(ct);
}
}
}
}
A few things to note:
You need to make each control ID unique when adding it to the asp:Panel (called pnlFieldCalculations).
The LoadControl method allows you to pass initial arguments
This question already has answers here:
Better way to find control in ASP.NET
(9 answers)
Closed 4 years ago.
I'm sorry, but I can't understand why this doesn't work. After compile, I receive a "Null reference exception". Please help.
public partial class labs_test : System.Web.UI.Page
{
protected void Button1_Click(object sender, EventArgs e)
{
if (TextBox1.Text != "")
{
Label Label1 = (Label)Master.FindControl("Label1");
Label1.Text = "<b>The text you entered was: " + TextBox1.Text + ".</b>";
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Label Label1 = (Label)Master.FindControl("Label1");
Label1.Text = "<b>You chose <u>" + DropDownList1.SelectedValue + "</u> from the dropdown menu.</b>";
}
}
and UI:
<%# Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="test.aspx.cs" Inherits="labs_test" Title="Untitled Page" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
Type in text and then click button to display text in a Label that is in the MasterPage.<br />
This is done using FindControl.<br />
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Submit" /><br />
<br />
Choose an item from the below list and it will be displayed in the Label that is
in the MasterPage.<br />
This is done using FindControl.<br />
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" OnSelectedIndexChanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem>Item 1</asp:ListItem>
<asp:ListItem>Item 2</asp:ListItem>
<asp:ListItem>Item 3</asp:ListItem>
</asp:DropDownList>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
</asp:Content>
Courtesy of Mr. Atwood himself, here's a recursive version of the method. I would also recommend testing for null on the control and I included how you can change the code to do that as well.
protected void Button1_Click(object sender, EventArgs e)
{
if (TextBox1.Text != "")
{
Label Label1 = FindControlRecursive(Page, "Label1") as Label;
if(Label1 != null)
Label1.Text = "<b>The text you entered was: " + TextBox1.Text + ".</b>";
}
}
protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
{
Label Label1 = FindControlRecursive(Page, "Label1") as Label;
if (Label1 != null)
Label1.Text = "<b>You chose <u>" + DropDownList1.SelectedValue + "</u> from the dropdown menu.</b>";
}
private Control FindControlRecursive(Control root, string id)
{
if (root.ID == id) return root;
foreach (Control c in root.Controls)
{
Control t = FindControlRecursive(c, id);
if (t != null) return t;
}
return null;
}
When Label1 exists on the master page:
How about telling the content page where your master page is
<%# MasterType VirtualPath="~/MasterPages/PublicUI.Master" %>
Then making a method in the master like
public void SetMessage(string message)
{
Label1.Text = message;
}
And call it in page's code behind.
Master.SetMessage("<b>You chose <u>" + DropDownList1.SelectedValue + "</u> from the dropdown menu.</b>");
When Label1 exists on the content page
If it is simply on the same page, just call Label1.Text = someString;
or if you for some reason need to use FindControl, change your Master.FindControl to FindControl
FindControl only searches in the immediate children (technically to the next NamingContainer), not the entire control tree. Since Label1 is not an immediate child of Master, Master.FindControl won't locate it. Instead, you either need to do FindControl on the immediate parent control, or do a recursive control search:
private Control FindControlRecursive(Control ctrl, string id)
{
if(ctrl.ID == id)
{
return ctrl;
}
foreach (Control child in ctrl.Controls)
{
Control t = FindControlRecursive(child, id);
if (t != null)
{
return t;
}
}
return null;
}
(Note this is convenient as an extension method).