Label Click
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I am new to asp and I want a clickable label within another control public class MyLabel : Label, IPostBackEventHandler{ public event EventHandler Click; protected virtual void onclick(EventArgs e){ if(this.Click != null){ this.Click(this, e); } } public void RaisePostBackEvent(string eventArgument){ onclick(new EventArgs()); } protected override void AddAttributesToRender(HtmlTextWriter writer) base.AddAttributesToRender (writer); writer.AddAttribute(HtmlTextWriterAttribute.onclick, Page.GetPostBackEventReference(this)); } } In my other control I have the following: protected override void Render(HtmlTextWriter output) { MyLabel ML=new MyLabel(); ML.Text = "TEST"; ML.Click += new System.EventHandler(this.ML_Click); base.Controls.Add(ML); base.Render(output); } private void ML_Click(object sender, EventArgs e) { Console.WriteLine(e.ToString()); } When I click on MyLabel in the main control it fires but it never gets into ML_Click and AddAttributesToRender but not anywhere else, what am I missing? any ideas?
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I am new to asp and I want a clickable label within another control public class MyLabel : Label, IPostBackEventHandler{ public event EventHandler Click; protected virtual void onclick(EventArgs e){ if(this.Click != null){ this.Click(this, e); } } public void RaisePostBackEvent(string eventArgument){ onclick(new EventArgs()); } protected override void AddAttributesToRender(HtmlTextWriter writer) base.AddAttributesToRender (writer); writer.AddAttribute(HtmlTextWriterAttribute.onclick, Page.GetPostBackEventReference(this)); } } In my other control I have the following: protected override void Render(HtmlTextWriter output) { MyLabel ML=new MyLabel(); ML.Text = "TEST"; ML.Click += new System.EventHandler(this.ML_Click); base.Controls.Add(ML); base.Render(output); } private void ML_Click(object sender, EventArgs e) { Console.WriteLine(e.ToString()); } When I click on MyLabel in the main control it fires but it never gets into ML_Click and AddAttributesToRender but not anywhere else, what am I missing? any ideas?
Hi there, What you are missing is the order of the events in the control life cycle[^]. Basically, the
"Render"phase occurs after the"Handle postback events", so when theClickevent gets fired you haven't registered the event handler for this event (the Render method still hasn't run yet), and as a result the event handler never gets called. In this case, instead of overriding theRendermethod, you should override theCreateChildControlsmethod where you'd normally use to create the child controls for a web custom control. The sample code looks something like:protected override void CreateChildControls()
{
MyLabel ML = new MyLabel();
ML.Text = "TEST";
ML.Click += new System.EventHandler(this.ML_Click);Controls.Add(ML);}
For more information, you can see Developing ASP.NET Server Controls[^]
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Hi there, What you are missing is the order of the events in the control life cycle[^]. Basically, the
"Render"phase occurs after the"Handle postback events", so when theClickevent gets fired you haven't registered the event handler for this event (the Render method still hasn't run yet), and as a result the event handler never gets called. In this case, instead of overriding theRendermethod, you should override theCreateChildControlsmethod where you'd normally use to create the child controls for a web custom control. The sample code looks something like:protected override void CreateChildControls()
{
MyLabel ML = new MyLabel();
ML.Text = "TEST";
ML.Click += new System.EventHandler(this.ML_Click);Controls.Add(ML);}
For more information, you can see Developing ASP.NET Server Controls[^]
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Hi there, What you are missing is the order of the events in the control life cycle[^]. Basically, the
"Render"phase occurs after the"Handle postback events", so when theClickevent gets fired you haven't registered the event handler for this event (the Render method still hasn't run yet), and as a result the event handler never gets called. In this case, instead of overriding theRendermethod, you should override theCreateChildControlsmethod where you'd normally use to create the child controls for a web custom control. The sample code looks something like:protected override void CreateChildControls()
{
MyLabel ML = new MyLabel();
ML.Text = "TEST";
ML.Click += new System.EventHandler(this.ML_Click);Controls.Add(ML);}
For more information, you can see Developing ASP.NET Server Controls[^]
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May be the answer is called INamingContainer...oof. But it still fires the main control from the begining. I would think that it would just call ML_Click.
Yes, you need to make sure that your parent custom control implement the
INamingContainerinterface so that it can route the postback event to the its child controlMyLabel. Also, you should remember that you'd nomally override theRendermethod when you want to control the interface of the custom control, that's not where you create a child control which needs to process a post back event. For more information, you can see Developing a Composite Control[^]