I want to create a usercontrol for retrieving and filtering a dataset. The problem I'm having is that the controls to be populated are not in the usercontrol, but on the main page on which the usercontrol exists. The reason for this is that the controls that are to be populated are different on each page.
If I could get some help solving the following simplified problem, I will probably be on my way to solve the bigger problem:
<body>
<form id="form1" runat="server">
<div>
<uc1:uc1 ID="uc1" runat="server" />
<asp:Label ID="lbl" runat="server"></asp:Label>
</div>
</form>
</body>
What I want to do is set the label on the main page by clicking a button on the usercontrol. Problem I'm having is that the usercontrol postback happens after the main page.
Thanks!
I managed to solve it by calling Parent.Page. I also implemented an interface so that I can call different pages' methods from the user control. Not sure if it's a good solution, but it will do:
interface IFilter
{
void SetLabel(string text);
}
public partial class uc : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btn_Click(object sender, EventArgs e)
{
((IFilter)Parent.Page).SetLabel("changed");
}
}
public partial class _Default : System.Web.UI.Page , IFilter
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
}
}
public void SetLabel(string text)
{
lbl.Text = text;
}
}
create a custom event in user control
create a property in usercontrol
fire the event when the button is clicked & set the property value
access the property in the main page in user control's eventhandler
Related
As i am new to asp.net i need some help from you,
i am using a MasterPage and child pages.
In master page I have a Label in which it shows the items added to cart.
when i am adding a product in products page.aspx it is updated in master page as (1 item) and showing in the label but when i am coming to homepage.aspx it is not showing i am using same master page in home.aspx.
If i refresh the home.aspx, it is updated. I need to update it without refreshing.
Sample code look like this
MasterPage markup: Here's the label in your masterpage which you want to be update from childpage
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
MasterPage.cs:
public partial class MasterPage : System.Web.UI.MasterPage
{
public string labeltext
{
get
{
return Label1.Text;
}
set
{
Label1.Text = value;
}
}
protected void Page_Load(object sender, EventArgs e)
{
}
}
ChildPage.cs:
protected void Page_Load(object sender, EventArgs e)
{
this.Master.labeltext = "Your value"; // set your value
}
Mark Up:
<asp:Label ID="Status" runat="server" Visible="false" />
Code Behind:
public partial class Files : System.Web.UI.Page
{
protected System.Web.UI.WebControls.Label Status;
protected void Page_Load(object sender, EventArgs e)
{
Status.
}
}
Now whenever I tried to use the label Status in the Page_Load handler I was warned as this member is defined more than once. My question is why I was not warned while redifining it as an instance member ? and actually is it possible to proceed with the control ?
You do not need this line:
protected System.Web.UI.WebControls.Label Status;
because when you declare a control in ASP.net layout it is automatically created as a field of your page class.
You have already used the Label Object Status in Designer. Can you check the designer .cs class for it's declaration? A variable with the same name can not be declared twice.
Corrected code is below...
Mark Up:
<asp:Label ID="Status" runat="server" Visible="false" />
Code Behind:
public partial class Files : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//Pseudo Code
//Status.PropertyName....
}
}
I have two UserControls - UserControl1.ascx and UserControl2.ascx in PageDefault.aspx:
How I can call the method (GetLabelText() in UserControl1.ascx) from UserControl2.ascx using event bubbling?
This is my example code - When I click on the button (UserControl2Button1 in UserControl1.ascx) - I want to call the method GetLabelText() from UserControl2.ascx - using event bubbling.
PageDefault.aspx:
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="PageDefault.aspx.cs" Inherits="TelerikAjaxEvents.PageDefault" %>
<%# Register TagPrefix="uc" TagName="UserControl1" Src="~/UserControl1.ascx" %>
<%# Register TagPrefix="uc" TagName="UserControl2" Src="~/UserControl2.ascx" %>
<!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>Page Default</title>
</head>
<body>
<form id="form1" runat="server">
UserControl1:
<uc:UserControl1 ID="UserControl1" runat="server" />
UserControl2:
<uc:UserControl2 ID="UserControl2" runat="server" />
</form>
</body>
</html>
UserControl1.ascx
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="UserControl1.ascx.cs" Inherits="TelerikAjaxEvents.UserControl1" %>
<asp:Label ID="UserControl1Label1" runat="server"></asp:Label>
UserControl1.ascx.cs
public partial class UserControl1 : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
public void GetLabelText()
{
UserControl1Label1.Text = "Text is Visible";
}
}
UserControl2.ascx
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="UserControl2.ascx.cs" Inherits="TelerikAjaxEvents.UserControl2" %>
<asp:Button ID="UserControl2Button1" runat="server" Text="Send"
onclick="UserControl2Button1_Click" />
UserControl2.ascx.cs
public partial class UserControl2 : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void UserControl2Button1_Click(object sender, EventArgs e)
{
//Call method from UserControl1 (GetLabelText()) - Show Label text - USING BUBBLE EVENT
}
}
There are many ways to go about this. Mark's answer hints at what was classically known as event bubbling using a built in functionality part of System.Web.UI.Control base control. However, it's a simple exercise to expose your own event, bind to it, and bubble up events through a control hierarchy. For more details on using BubbleEvent in ASP.NET read the following. Please keep in mind that both of these MSDN articles were written for .NET 1.1
Bubbling an Event
Event Bubbling Control Sample
K. Scott Allen does a good job at demonstrating exactly what an "event bubbling" implementation looks like in his post: Event Bubbling From Web User Controls in ASP.NET (C#) . See the following modification to your example for inspiration.
UserControl1 with GetLabelText()
public partial class UserControl1 : System.Web.UI.UserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
public void GetLabelText()
{
UserControl1Label1.Text = "Text is Visible";
}
}
UserControl2 with exposed BubbleClick event handler that callers can subscribe to.
public partial class UserControl2 : System.Web.UI.UserControl
{
protected Button UserControl2Button1;
protected void Page_Load(object sender, EventArgs e)
{
}
public event EventHandler BubbleClick;
protected void OnBubbleClick(EventArgs e)
{
if(BubbleClick != null)
{
BubbleClick(this, e);
}
}
protected void UserControl2Button1_Click(object sender, EventArgs e)
{
// do some stuff
OnBubbleClick(e);
}
}
PageDefault subscribes to UserControl2's BubbleClick event handler and executes UserControl1.GetLabelText()
public partial class PageDefault : WebPage
{
UserControl1 userControl1;
UserControl2 userControl2;
protected void Page_Load(object sender, EventArgs e)
{
UserControl2.BubbleClick += RootBubbleClickHandler;
}
protected void RootBubbleClickHandler(object sender, EventArgs e)
{
if (sender is UserControl2)
{
// subscribe UserControl1 to UserControl2 click event and do something
userControl1.GetLabelText();
}
// check for other controls with "BubbleClicks"
}
}
Event Bubbling is a poorly understood concept in ASP.NET WebForms. It does exist (and is used by most of the databound controls), but is often mistaken for the simpler concept of "implement an event in a user control" (as K Scott Allen does).
The core of event bubbling is that the event travels up through the control hierarchy until it is handled or hits the root. This allows some centralization of handler code. It is implemented using the Control.RaiseBubbleEvent and Control.OnBubbleEvent methods. The main use case is controls with a lot of child controls (think Repeaters, ListViews, etc.). Instead of subscribing to each individual control, the Repeater catches them all in it's OnBubbleEvent and raises a single ItemCommandEvent for them.
If you really wanted to use event bubbling (as opposed to K. Scott's example), it'd look something like:
class Page {
override bool OnBubbleEvent(object sender, EventArgs e) {
var btn = sender as Button;
if (btn == null) return false;
// You may want to do further checking that the source is what you want
// You could use CommandEventArgs to do this
this.uc1.GetLabelText();
return true;
}
}
The sequence of events goes like this:
- Button Clicked
- Button RaiseBubbleEvent
- UserControl OnBubbleEvent returns false (default, since you didn't override)
- Page OnBubbleEvent
Can you try declaring the UserControl1 as public property(e.g. "UserControl1") on the PageDefault.aspx and then in the UserControl2, use Parent.Page.UserControl1.GetLabelText()?
I created a textbox and a submit button in header(User Control) included in a master page
and I want to use that textbox value after clicking submit in my .aspx.vb page.
How can i access that, as the vb page is loaded first and then master page is loading ?
TextBox Val = (TextBox)this.Master.FindControl("TextBoxID");
The best way to communicate from UserControl to Page/MasterPage is using events
The best way to communicate from MasterPage to Page is using events
On this way you don't hardlink UserControls with their Pages/MasterPages and the Page with it's Master.
Add an event to your UserControl that is raised when the user clicks the button, for example:
In UserControl of type MyControl:
public delegate void SubmittedHandler(MyControl ctrl);
public event SubmittedHandler Submitted;
protected void BtnCLick(object sender, EventArgs e) {
Submitted(this);
}
Then add an handler to this event in your MasterPage, handle it and raise the Master's event again:
In Master's codebehind:
public delegate void MyControlSubmittedHandler(MyControl ctrl);
public event MyControlSubmittedHandler ControlSubmitted;
protected void Page_Init(Object sender, EventArgs e) {
this.MyControl1.Submitted += MyControlSubmitted;
}
protected void MyControlSubmitted(MyControl sender) {
ControlSubmitted(sender);
}
Then add an handler to this event to your page:
In your Page:
protected void Page_Init(object sender, EventArgs e) {
((SiteMaster)Master).ControlSubmitted += MasterControlSubmitted;
}
protected void MasterControlSubmitted(MyControl sender){
// do whatever you need to do
}
If you only need to access the TextBox from the page and you don't need to handle the click-event, you could also use properties to achieve this:
add a public property f.e. MyControlText in your UserControl that get/set the TextBox.Text property
add a public property f.e. MyControlText in your Master that get/set your UserControl's MyControlText property
Now you can get/set this property from your page in this way:
((SiteMaster)Master).MyControlText = "Hello World";
I want to have a user control containing a save button.
I want the click event attached to the save button to be handled by the containing page not the user control
Is this possible?
EDIT MORE SPECIFIC
Say I have a page called "Editor Page" and a user control called "Editor Buttons".
On the "Editor Buttons" user control I have a save button (which is a web control). I want the Click event of the save button to be handled by the "Editor Page" rather than the user control.
The reason for this is because I want to specify base pages that implement common behaviour.
This technique is commonly referred to as “event bubbling”.
Here is an exmple:
public partial class Test : System.Web.UI.UserControl
{
public event EventHandler buttonClick;
protected void Button1_Click(object sender, EventArgs e)
{
buttonClick(sender, e);
}
}
Then you can subscribe the event buttonClick at webpage to display the different information .
public partial class Test: System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
UserControlID.buttonClick+=new EventHandler(UserControlID_buttonClick);
}
protected void UserControlID_buttonClick(object sender, EventArgs e)
{
Response.Write("hello,I am jack.");
}
}
I will assume that you have the code for the UserControl. If that is the case, you can define a Save event in your user control and have it expose the Click event of the save button, either directly, or by internally setting up an event handler and raise the Save event when the button is clicked. That could look something like this in the UserControl:
public event EventHandler Save;
private void SaveButton_Click(object sender, EventArgs e)
{
OnSave(e);
}
protected void OnSave(EventArgs e)
{
// raise the Save event
EventHandler save = Save;
if (save != null)
{
save(this, e);
}
}
UserControl1.ascx
UserControl1.ascx.cs
public partial class UserControl1 : System.Web.UI.UserControl
{
public event EventHandler UserControl1Click;
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btn1_Click(object sender, EventArgs e)
{
UserControl1Click(sender, e);
}
}
UserControl2.ascx
UserControl1.ascx.cs
public partial class UserControl2 : System.Web.UI.UserControl
{
public event EventHandler UserControl2Click;
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btn2_Click(object sender, EventArgs e)
{
UserControl2Click(sender, e);
}
}
Then add one Asp.Net Text box(to display user control id) and above two user controls to Aspx page as shown below.
<title>Untitled Page</title>
<form id="form1" runat="server">
<div>
<asp:TextBox ID="txt1" runat="server"></asp:TextBox> <br />
<UC1:UC ID="uc1" runat="server" />
<UC1:UC ID="uc2" runat="server" />
</div>
</form>
Now add event handler for each user control to handle button click event of two controls as shown below.
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
uc1.UserControl1Click += new EventHandler(uc1_UserControl1Click);
uc2.UserControl2Click += new EventHandler(uc2_UserControl2Click);
}
protected void uc1_UserControl1Click(object sender, EventArgs e)
{
txt1.Text = "User Control 1 Clicked";
}
protected void uc2_UserControl2Click(object sender, EventArgs e)
{
txt1.Text = "User Control 2 Clicked";
}
}
If we click User Control1, text box displays “User Control 1 Clicked” or if we click on User Control2, text box displays “User Control 2 Clicked”.