Question

Event handling in asp.net

Asked by: TheCommunicator

Being a VB  programmer, event handling  had been straight forward. Open the code file and you can see all the controls in the left dropdown and all the related events on the right dropdown.

ASP.Net with C# is something different. For example, I have raised Button_click event on "onclick"
HTML event of a button. Now,I go to my aspx.cs file  then do I have to write the whole function definition code by my self?

I mean to ask is that does everything have to be handwritten? No automation like selection of the controls and selection of related events?

This Question has been solved and asker verified All Experts Exchange premium technology solutions are available to subscription members.

Subscribe now for full access to Experts Exchange and get

Instant Access to this Solution

  • Plus...
  • 30 Day FREE access, no risk, no obligation
  • Collaborate with the world's top tech experts
  • Unlimited access to our exclusive solution database
  • Never be left without tech help again

Subscribe Now

Asked On
2009-10-14 at 12:18:44ID24812546
Topics

C# Programming Language

,

Programming for ASP.NET

Participating Experts
2
Points
500
Comments
11

Trusted by hundreds of thousands everyday for fast, accurate and reliable tech support.

  • "The time we save is the biggest benefit of Experts Exchange to Warner Bros. What could take multiple guys 2 hours or more each to find is accessed in around 15 minutes on Experts Exchange." Mike Kapnisakis, Warner Bros.
  • "Our team likes having a resource that is more secure than just using Google and most experts using this service really know their stuff. It's nice to look here first versus using Google." Dayna Sellner, Lockheed Martin
  • "Anytime that I've been stumped with a problem, 9 out of 10 times Experts Exchange has either the accepted solution or an open discussion of the potential solution to the problem." Kenny Red, eBay Inc.

See what Experts Exchange can do for you.

Got a question?

We've got the answer.

Experts Exchange has been collecting answers to technology questions since 1996…3 million and counting! If you have a question, chances are we already have your answer.

Screenshot of Experts Exchange Knowledgebase

Need individual assistance?

Our experts are ready to help.

If you can't find the exact answer you're looking for, ask our exclusive community of 50,000 experts. You’ll get a personalized answer from a trusted professional.

Screenshot of Experts Exchange Knowledgebase

Want to learn from the best?

Read articles from industry experts.

Thousands of free tech tips, tricks, how-to’s and tutorials are available in our peer reviewed articles section. See for yourself how smart our experts are, no login required.

Screenshot of an Article

Working on a long term project?

Store your work and research.

Save solutions to your questions, answers you’ve discovered through searching plus helpful articles in your personal knowledgebase for easy future access.

Screenshot of Experts Exchange Knowledgebase

Access the answers to your technology questions today.

Subscribe Now

30-day free trial. Register in 60 seconds.

What Makes Experts Exchange Unique?

Members of the expert community talk about why the experience at Experts Exchange is different than what you will find anywhere else.

Trusted by the world's most respected brands.

image of each brand's logo

Faithfully serving IT professionals since 1996.

Experts Exchange Logo

Try it out and discover for yourself.

Subscribe Now

30-day free trial. Register in 60 seconds.

Related Solutions

  1. OnClick and onClick ?
    I put an "OnClick" attribute into my asp.net WebControl, to call a process: <asp:button id="Button1" runat="server" Text="Button" OnClick="myButtonModule"></asp:button></td> So, what is the difference betwe...
  2. ASP.Net and Javascript OnClick Event Postback problems
    I have an ASP.NET webpage which has a radio button list list with three options None First Second I then added code in my Page Load to add an onClick javascript Attribute to each of the radio buttons so When "None" is clicked, all table rows dissapear When "F...
  3. ASP.NET Dropdown control refresh
    Codebase: ASP.NET, VB Synopsois: i am creating a contact input screen in which i have a dropdown control called "Contact_Type" if the type the user wants to use is not available in the dropdown control they can push an "Edit" button next to the control to...
  4. CSS Button onclick event  href="#" onclick="
    Ok this is really bugging me. How do you correctly call a procedure from the href="#" onclick=" eg I want to call Protected Sub ABC() from the onclick event of a css button I have tried <a class="button" href="#" onclick="ABC();&...

Free Tech Articles

  1. WARNING: 5 Reasons why you should NEVER fix a computer for free.
    It is in our nature to love the puzzle. We are obsessed. The lot of us. We love puzzles. We love the challenge. We thrive on finding the answer. We hate disarray. It bothers us deep in our soul. W...
  2. SCCM OSD Basic troubleshooting
    SCCM 2007 OSD is a fantastic way to deploy operating systems, however, like most things SCCM issues can sometimes be difficult to resolve due to the sheer volume of logs to sift through and the dispe...
  3. Migrate Small Business Server 2003 to Exchange 2010 and Windows 2008 R2
    This guide is intended to provide step by step instructions on how to migrate from Small Business Server 2003 to Windows 2008 R2 with Exchange 2010. For this migration to work you will need the fo...
  4. Create a Win7 Gadget
    This article shows you how to create a simple "Gadget" -- a sort of mini-application supported by Windows 7 and Vista. Gadgets can be dropped anywhere on the desktop to provide instant information, ...
  5. Outlook continually prompting for username and password
    There have been a lot of questions recently regarding Outlook prompting for a username and password whilst using Exchange 2007. There are a few reasons why this would happen and I will try to cover t...
  6. Backup Exchange 2010 Information Store using Windows Backup
    There seems to be quite a lot of confusion around the ability to backup Exchange 2010 using the built in Windows Backup feature. This stems from the omission of this feature prior to Exchange 2007 s...

Cloud Class Webinars

  1. Avoiding Bugs in Microsoft Access
    Alison Balter takes and in-depth look at avoiding bugs in Access. In this webinar you will learn about using the immediate window to debug your applications, invoking the debugger, using breakpoints to troubleshoot, stepping through code, setting the next statement to execute, ...
  2. Top 10 Best New Features in Visio 2010
    Scott Helmers gives live demonstrations of the top 10 new features in Visio 2010. This webinar will teach you how to create compelling diagrams by adding shapes to the page with a single click, linking the shapes in a diagram to data in Excel (or SQL Server, or SharePoint), ...
  3. IT Consultant Business Secrets Revealed
    Michael Munger, Experts Exchange tech pro and IT consultant, pulls back the curtain on his very successful businesses and answers question on every IT consultant and business owner should know about. He shares secrets on what he did to solve the 5 most common problems in IT, ...
  4. Disaster Recovery and Business Continuity
    Quest CTO, Mike Billon, gives an overview of the steps involved in building a dunamic disaster recovery plan. Through case studies and an examination of software/hardware tooles for monitoring and testing, you'll gain a better understandin of where you are, where you want ...
  5. Organize Your Visio Diagrams with Containers and Lists
    Scott Helmers uses cross functional flowcharts, wireframe diagrams, data graphic legends and seating charts to teach you: how to ustilize all three new structured diagram components in Visio 2010, the best practices for organizeing shapes in previous version of Visio, how to organize ...
  6. How to Us Objects, Properties, Events and Methods in Microsoft Access
    Alison Dalter gives an in-depbth look at objects, properties, events and methods in Microsoft Access. In this webinar you will learn about using the object browser, referring to objects, working with properties and methods, working with object variables, understanding the ...

Join the Community

Give a Little. Get a Lot.

Join the community of experts here and help other tech pros by answering question in your area of expertise. You can earn FREE access to all Experts Exchange's premium features and resources.

Join the Community

Answers

 

by: sammy1971Posted on 2009-10-14 at 12:30:39ID: 25574177

You can either double click the control to generate the default event
or if you find the event name in the property window ", Right click on the control, click on properties,the property window will appear on the right,  You will see a thunder icon" click the event to create it

 

by: Omego2KPosted on 2009-10-14 at 12:36:19ID: 25574233

Yes and no. You can actually hook events in the code behind. Use visual studio you get a little help creating the handlers. So on page load to hook the click event to the button you would do:

ButtonObject.Click+=new EventHandler(Button2_Click);

Now where the help comes in is after you type "+=" you press tab twice which auto generates the event handler.
Now the event handler is generated without an access modifier it's just:

void Button2_Click(object sender, EventArgs e)
    {
        throw new NotImplementedException();
    }

no modifier means that it's private

You can keep it as is and remove the onclick part from the aspx page because the event handler hooks in the .cs file OR do what I do. Delete the line that hooks the event which is: "ButtonObject.Click+=new EventHandler(Button2_Click);" and add the protected modifier to the handler so it looks like this:

protected void Button2_Click(object sender, EventArgs e)
    {
        throw new NotImplementedException();
    }

and on the aspx have onclick="Button2_Click"

Yes it is more work in C# but there is some help. In a windows application this is even easier as you can look in the control's properties in the designer and double click the event you want.

 

by: TheCommunicatorPosted on 2009-10-14 at 12:36:32ID: 25574235

If I double click, it opens aspx  source file,where I can say that "onclick= Button1_click. But I define Button1_click in aspx.cs file, right? So is there any way to generate Button1_click definition body ?

something like this:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles

end sub()

and I write my code in between?

 

by: TheCommunicatorPosted on 2009-10-14 at 13:11:47ID: 25574608

Wow that was a great explanation omega. Thank you very much. SO I  think that is more of a Vb and C# difference rather than a desktop application and web application difference. I  have one more question related to previous post:

1.  where do I write "ButtonObject.Click+=new EventHandler(Button2_Click);" and "void Button2_Click(object sender, EventArgs e)" in my aspx.cs file EXACTLY?
   

 

by: Omego2KPosted on 2009-10-14 at 13:16:45ID: 25574659

page load event

 

by: Omego2KPosted on 2009-10-14 at 13:17:31ID: 25574666

But I tested sammy197's solution and it does work, I never knew that. It seems it would be easier to go with his.

 

by: TheCommunicatorPosted on 2009-10-14 at 13:39:17ID: 25574914

Ok I have done somehing like this:

aspx:

asp:Button ID="Button1" runat="server"
        style="z-index: 1; left: 277px; top: 277px; position: absolute"
        Text="Button" onclick="Button1_Click" />

aspc.cs:

namespace MyFirstWebApplication
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            Button1.Click += new EventHandler(Button1_Click);
        }
        private void Button_click(object sender, EventArgs e) {
            Button1.Text = " hello";  
        }

    }

It tells me that Button1_click  Does nto exist in current context. Hows that?

 

by: Omego2KPosted on 2009-10-14 at 13:46:02ID: 25575018

you do not need the onclick part in the
<asp:Button ID="Button1" runat="server"
        style="z-index: 1; left: 277px; top: 277px; position: absolute"
        Text="Button" onclick="Button1_Click" />

so change it to:
<asp:Button ID="Button1" runat="server"
        style="z-index: 1; left: 277px; top: 277px; position: absolute"
        Text="Button" onclick="Button1_Click" />

if you would like to use the declarative event hooking and have the onclick you would need to change your code behind to look like this:

namespace MyFirstWebApplication
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
 
        }
        protected void Button_click(object sender, EventArgs e) {
            Button1.Text = " hello";  
        }

    }
}

 

by: Omego2KPosted on 2009-10-14 at 13:46:47ID: 25575033

oh I'm sorry where I say
"so change it to:
<asp:Button ID="Button1" runat="server"
        style="z-index: 1; left: 277px; top: 277px; position: absolute"
        Text="Button" onclick="Button1_Click" /> "

I meant
so change it to:
<asp:Button ID="Button1" runat="server"
        style="z-index: 1; left: 277px; top: 277px; position: absolute"
        Text="Button" />

 

by: TheCommunicatorPosted on 2009-10-14 at 14:04:47ID: 25575256

Okie I did exactly as you said in scenario 1:

aspx:

<asp:Button ID="Button1" runat="server"
        style="z-index: 1; left: 277px; top: 277px; position: absolute"
        Text="Button" />  
</div>

aspx.cs

namespace MyFirstWebApplication
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        { Button1.Click += new EventHandler(Button1_Click); }


        protected void Button1_Click(object sender, EventArgs e)
        {
            Button1.Text = " hello";  
        }
    }      
}  


Good news : No error
Bad news: Text property of the button is not changed when I click it on runtime

 

by: TheCommunicatorPosted on 2009-10-14 at 14:58:26ID: 25575650

I think this is time to distribute the. I will  initiate a new question for this  section of the problem. Thank you very much for your help guys.

20120131-EE-VQP-002

3 Ways to Join

30-Day Free Trial

The Experts

98% positive feedback on 31,087 answers since March 2000. angeliii is a Microsoft Most Valuable Professional for his work with MS SQL Server & Develoment.

He has also proven his knowledge of Visual Basic Programming, PHP Scripting and Oracle Databases.

The Experts

97% positive feedback on 10,752 answers since July 2000. lrmoore has more than 18 years experience in the networking industry.

The six-time Mircosoft MVPs specialties include firewalls, virtual private networking, and network management.

Testimonials

"...and excellent source for support... Kind of like having your very own IT dept." Electriciansnet

Testimonials

"I was apprehensive at signing up at first. However... it has already made my life as an IT administrator much easier." JaCrews

Testimonials

"WOW! You guys have great, active, and knowledgeable people on here." moore50

Business Clients

Business Clients

In the Press

"If you’ve got a question... Experts Exchange can supply an answer.”

In the Press

"...an invaluable aid for both IT professionals and those who require tech support."

In the Press

"where IT professionals provide quick answers on just about any topic"

Business Account Plans

Loading Advertisement...