Remove From My Forums

Not able to fire the event on dynamically created checkbox in webforms

Question

User-534047397 posted

Hi ,

I have dynamically created the checkbox using Literal from code behind. It's not triggering any event / function.

I tried onclick , onserverchange methods. But these also not working. Please suggest any idea to resolve this problem.

Here is my code

public void CreateDynamicCheckbox()
{
   StringBuilder stbuilder= new StringBuilder();
   for (int i = 1; i < 6; i++) 
   {
      stbuilder.Append("<li><input type = 'checkbox' id= 'chk" + i.ToString() + "' class='side-checkbox' runat='server' onserverchange ='callfunction' value='" + i.ToString() + "'/></li>");
      DivTagASPControl.Controls.Add(new Literal { Text = stbuilder.ToString() }); 
   }
}
public void callfunction()        
{ 
      //some code        
}

Wednesday, July 18, 2018 11:38 AM

Answers

User-1171043462 posted

You cannot build Server Side controls using String concatenation.

You can create a dynamic CheckBoxList as shown below

HTML

<form id="form1" runat="server">
<asp:Panel ID = "Panel1" runat="server">
</asp:Panel>
</form>

Code

    protected void Page_Load(object sender, EventArgs e)
    {

        CheckBoxList checkBoxList = new CheckBoxList();
        for (int i = 1; i < 6; i++)
        {
            checkBoxList.Items.Add(new ListItem
            {
                Value = i.ToString(),
                Text = i.ToString()
            });
        }
        checkBoxList.AutoPostBack = true;
        checkBoxList.SelectedIndexChanged += new EventHandler(CheckBoxList_SelectedIndexChanged);
        Panel1.Controls.Add(checkBoxList);
    }

    protected void CheckBoxList_SelectedIndexChanged(object sender, EventArgs e)
    {
        foreach (ListItem item in (sender as CheckBoxList).Items)
        {
            if (item.Selected)
            {
                string text = item.Text;
                string value = item.Value;
            }
        }
    }

Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM

Wednesday, July 18, 2018 1:06 PM

User-369506445 posted

your code is not correct,

if you want to call a code behind <g data-gr-id="260" id="260" class="gr_ gr_260 gr-alert gr_gramm Grammar only-ins replaceWithoutSep">method</g>, you have to use an asp control like <g class="gr_ gr_14 gr-alert gr_spell gr_inline_cards gr_disable_anim_appear ContextualSpelling" id="14" data-gr-id="14"><g class="gr_ gr_142 gr-alert gr_gramm gr_inline_cards gr_run_anim Grammar only-ins doubleReplace replaceWithoutSep" id="142" data-gr-id="142">mudassarkhan</g></g> sample

if you want to call a <g class="gr_ gr_16 gr-alert gr_spell gr_inline_cards gr_disable_anim_appear ContextualSpelling ins-del" id="16" data-gr-id="16">java script</g> function use below like :

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server"> 
    <script>
        function callfunction(parameters) {
           
            alert(parameters);
        }
    </script>
    
</head>
<body>
 <form runat="server">
   <ul>
       <div id="DivTagASPControl" runat="server" ></div>
   </ul>
      
 </form>
</body>
</html>

code behind

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                CreateDynamicCheckbox();
            }
             
        }

        public void CreateDynamicCheckbox()
        {
            StringBuilder stbuilder = new StringBuilder();
            for (int i = 1; i < 6; i++)
            {
                stbuilder.Append("<li><input type = 'checkbox' id= 'chk" + i.ToString() + "' class='side-checkbox' runat='server' onclick ='callfunction("+i+");' value='" + i.ToString() + "'/></li>");
                
            }
            DivTagASPControl.Controls.Add(new Literal { Text = stbuilder.ToString() });
        }

Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM

Wednesday, July 18, 2018 1:41 PM

All replies

0

Sign in to vote

User475983607 posted

Correct, you cannot string build a server control as you've experienced. You must add the control to the markup or add the control in the code behind.

The recommended approach in web forms is to use a data binding control like a repeater to create dynamic controls as that's what data bound controls are for. The Getting Started tutorials on this site explain Web Forms fundamentals and common programming patterns.

https://www.asp.net/web-forms/overview/getting-started

Data bound controls.

https://www.asp.net/web-forms/overview/aspnet-data-controls

Wednesday, July 18, 2018 11:50 AM