ASP.Net Custom Server Control Not Firing Custom Event

Question

I have created a custom server control. It looks great and the rendered HTML is also as it should be. I initially had it extending the ControlContainer and now it extends the WebControl (both behave the same.) It has two properties, ImageUrl and Text. Essentially it will render a generic HTML tag with an and tags within it.

My problem is that the ServerClick event that is exposed (by NamingContainer I beleive) doesn't seem to fire. If I add any of the ASP buttons (Link, Image or regular) and associate to that Click event it fires but of course I have extra rendered content. It successfully runs the javascript and does the __dopostback call. But it must not see the given control ID or something because the event never gets fired.

using System;
using System.ComponentModel;
using System.Drawing.Design;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;

namespace PLSO.Info.Web.UI {

[DefaultEvent("Submit")]
[DefaultProperty("Text")]
[ToolboxData("<{0}:ComboButton runat=\"server\"> </{0}:ComboButton>")]
public class ComboButton : WebControl {

    private HtmlImage imageControl;
    private HtmlGenericControl spanControl;

    private static readonly object EventSubmitKey = new object();

    [Bindable(true)]
    [Category("Appearance")]
    [DefaultValue("")]
    [Description("The text to display on the button.")]
    public string Text {
        get { return ViewState["NewText"] as string; }
        set { ViewState["NewText"] = value; }
    }

    [DefaultValue("")]
    [Bindable(true)]
    [Category("Appearance")]
    [UrlProperty()]
    [Editor("System.Web.UI.Design.ImageUrlEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
    public string ImageUrl {
        get {
            EnsureChildControls();
            return this.imageControl.Src;
        }
        set {
            EnsureChildControls();
            this.imageControl.Src = value;
        }
    } // ImageUrl - Property

    public override string CssClass {
        get { return ViewState["CssClass"] as string; }
        set { ViewState["CssClass"] = value; }
    }

    [Category("Action")]
    [Description("Raised when the user clicks the button.")]
    public event EventHandler Submit {
        add { Events.AddHandler(EventSubmitKey, value); }
        remove { Events.RemoveHandler(EventSubmitKey, value); }
    }

    protected virtual void OnSubmit(EventArgs e) {
        EventHandler SubmitHandler = (EventHandler)Events[EventSubmitKey];

        if (SubmitHandler != null)
            SubmitHandler(this, e);
    }

    void ComboButton_Submit(object sender, EventArgs e) {
        OnSubmit(EventArgs.Empty);
    }

    protected override void CreateChildControls() {
        Controls.Clear();

        imageControl = new HtmlImage();
        imageControl.Src = this.ImageUrl;
        imageControl.Alt = this.Text;
        this.Controls.Add(imageControl);

        spanControl = new HtmlGenericControl("span");
        spanControl.InnerText = this.Text;
        this.Controls.Add(spanControl);

        this.Submit += new EventHandler(ComboButton_Submit);

        ChildControlsCreated = true;
    }

    protected override void Render(HtmlTextWriter writer) {
        PostBackOptions pbo = new PostBackOptions(this);

        AddAttributesToRender(writer);
        writer.AddAttribute(HtmlTextWriterAttribute.Class, this.CssClass);
        writer.AddAttribute("onclick", string.Format("javascript:{0}", Page.ClientScript.GetPostBackEventReference(pbo)));
        writer.RenderBeginTag(HtmlTextWriterTag.Button);
        imageControl.RenderControl(writer);
        spanControl.RenderControl(writer);
        writer.RenderEndTag();
    }
    }
}

Here is my markup. I put in this control and then a regular ASP:Button. That regular button's event gets hit! Not mine.

<ucs:ComboButton ID="btnT4" runat="server" Text="Please" CssClass="PButtonCombo" ImageUrl="~/Styles/icons/edit-find.png" OnSubmit="btnT4_Submit" />
<asp:Button ID="btnT5" runat="server" Text="TEST" onclick="btnT5_Click" UseSubmitBehavior="False" />

And here is the rendered HTML:

<button id="MainContent_btnT4" class="PButtonCombo" onclick="javascript:__doPostBack(&#39;ctl00$MainContent$btnT4&#39;,&#39;&#39;)"><img src="../Styles/icons/edit-find.png" alt="Please" /><span>Please</span></button>
<input type="button" name="ctl00$MainContent$btnT5" value="TEST" onclick="javascript:__doPostBack(&#39;ctl00$MainContent$btnT5&#39;,&#39;&#39;)" id="MainContent_btnT5" />

I have to believe I am close but just missing something. Been tweaking it for hours today, PLEASE HELP!

EDIT:

Thanks to @James answer, all I did was add the following to the top of the above example. It did the trick but now fires twice. Not sure why? So that is my current question:

public class ComboButton : WebControl, IPostBackEventHandler {

    public void RaisePostBackEvent(string eventArgument) {
        OnClick(new EventArgs());
    }

    [Category("Action")]
    [Description("Raised when the user clicks the button.")]
    public event EventHandler Click;

    protected virtual void OnClick(EventArgs e) {
        if (Click != null)
            Click(this, e);
    }

EDIT 2 == SOLUTION

using System.ComponentModel;
using System.Drawing.Design;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;

namespace PLSO.Info.Web.UI {

[DefaultEvent("Submit")]
[DefaultProperty("Text")]
[ToolboxData("<{0}:ComboButton runat=\"server\"> </{0}:ComboButton>")]
public class ComboButton : Button {

    private HtmlImage imageControl;
    private HtmlGenericControl spanControl;

    [DefaultValue("")]
    [Bindable(true)]
    [Category("Appearance")]
    [UrlProperty()]
    [Editor("System.Web.UI.Design.ImageUrlEditor, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", typeof(UITypeEditor))]
    public string ImageUrl {
        get {
            EnsureChildControls();
            return this.imageControl.Src;
        }
        set {
            EnsureChildControls();
            this.imageControl.Src = value;
        }
    } // ImageUrl - Property

    protected override void CreateChildControls() {
        Controls.Clear();

        imageControl = new HtmlImage();
        imageControl.Src = this.ImageUrl;
        imageControl.Alt = this.Text;
        this.Controls.Add(imageControl);

        spanControl = new HtmlGenericControl("span");
        spanControl.InnerText = this.Text;
        this.Controls.Add(spanControl);

        ChildControlsCreated = true;
    } // CreateChildControls - Method - Override

    protected override void Render(HtmlTextWriter writer) {
        PostBackOptions pbo = new PostBackOptions(this);

        AddAttributesToRender(writer);
        writer.RenderBeginTag(HtmlTextWriterTag.Button);
        imageControl.RenderControl(writer);
        spanControl.RenderControl(writer);
        writer.RenderEndTag();
    } // Render - Event - Override
  }
}

James Johnson · Accepted Answer · 2011-10-12 20:16:07Z

3

Try implementing the IPostBackEventHandler interface:

public class ComboButton : WebControl, IPostBackEventHandler  
{
    public void RaisePostBackEvent(string eventArgument)
    {
        OnSubmit(EventArgs.Empty); 
    }
}

Here's an article that explains the implementation of the IPostBackEventHandler interface:
http://msdn.microsoft.com/en-us/library/system.web.ui.ipostbackeventhandler.aspx

EDIT

If your events are in some way dependent on data, you need to implement the IPostBackDataHandler interface. For example, you would use the IPostBackDataHandler interface to fire the OnTextChanged event of a TextBox:

public class ComboButton : WebControl, IPostBackDataHandler  
{
    public virtual bool LoadPostData(string postDataKey, NameValueCollection postCollection)
    {
        return true;
    }

    public virtual void RaisePostDataChangedEvent()
    {

    }
}

Here's an article that explains the implementation of the IPostBackDataHandler interface:
http://msdn.microsoft.com/en-us/library/system.web.ui.ipostbackdatahandler.aspx

edited Oct 12, 2011 at 20:16

answered Oct 12, 2011 at 19:40

James Johnson

46.1k8 gold badges75 silver badges111 bronze badges

Sign up to request clarification or add additional context in comments.

11 Comments

James Johnson Over a year ago

Sorry, I meant IPostBackEventHandler

Grandizer Over a year ago

That did it (MOSTLY) - Now the event fires twice. See my answer below so I can post code.

James Johnson Over a year ago

You probably just need to rework your event handler logic a little bit. What answer are you referring to?

Grandizer Over a year ago

I tried to put the code in these comments but it treats it like a paragraph and thus is painfull to read. So I figured if I could answer it (since I do not see a reply) that would help, but that was not the answer either. So I just EDITED the initial post - see after the EDIT statement.

James Johnson Over a year ago

Try just moving the OnSubmit(EventArgs.Empty) to the RaisePostBackEvent method, and remove the OnClick event handler from the CreateChildControls method.

|

Arturo Martinez · Accepted Answer · 2011-10-12 19:41:26Z

2

You need to look into IPostBackEventHandler

If you dont implement this interface in your control ASP.net engine wont forward the events to your control.

answered Oct 12, 2011 at 19:41

Arturo Martinez

2,5831 gold badge23 silver badges37 bronze badges

Collectives™ on Stack Overflow

ASP.Net Custom Server Control Not Firing Custom Event

2 Answers 2

11 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

11 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related