How to get Controls ID from code behind on page load

Question

5.00/5 (1 vote)

See more:

VB

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
      Dim lbl_Date As New Label
      Dim i as int16
      i = 20
      While (i < i + 1)
         lbl_Date = TryCast(Page.FindControl("lbl_Date" + i.ToString), Label)
         lbl_Date = "Value"
     i = i + 1
     End While
  End Sub

This is returning Nothing in `lbl_Date` variable. If i don't use this in `Page_Load`, it works just fine. Only in `Page_Load` it doesn't work.

Explanation :::: Well what i am trying to do here is . i have 100 label name are lable1 to lable100. I can do like label1 =Value and label2 =Value and so on but i am trying to put in loop so i have less code. just for the Info... This code work but not in Page_Load , I am thinking this has to do with page life cycle

Posted 18-Apr-12 8:20am

anjumnavid

Updated 18-Apr-12 9:35am

v4

Add a Solution

Comments

R. Giskard Reventlov 18-Apr-12 14:46pm

Are you getting an exception? If so, what is it? Why are you appending 1 to the control names in that manner? I see you've asked the same question elsewhere.

anjumnavid 18-Apr-12 15:06pm

Yes i asked this question elsewhere too.

Well what i am trying to do here is . i have 100 label name are lable1 to lable100. I can do like label1 =1 and label2 =2 and so on but i am trying to put in loop so i have less code. just for the Info... This code work but not in Page_Load , I am thinking every one looking to the code but this has to do with page life cycle

4 solutions

Solution 1

When the control is rendered to html, it might have a diferent ID, the property is named ClientID, but if you want just to change all controls, just place them inside a container and check for them.

on the asp.net would be like this:

XML

<div id="mycontainer" runat="server">
        <asp:Label runat="server" ID="label1" Text="label 1"></asp:Label>
        <asp:Label runat="server" ID="label2" Text="label 2"></asp:Label>
        <asp:Label runat="server" ID="label3" Text="label 3"></asp:Label>
        <asp:Label runat="server" ID="label4" Text="label 4"></asp:Label>
        <asp:Label runat="server" ID="label5" Text="label 5"></asp:Label>
        <asp:Label runat="server" ID="label6" Text="label 6"></asp:Label>
        <asp:Label runat="server" ID="label7" Text="label 7"></asp:Label>
        <asp:Label runat="server" ID="label8" Text="label 8"></asp:Label>
    </div>

and the code behind (c# in this case) is like this:

C#

protected void Page_Load(object sender, EventArgs e)
    {
        foreach (var control in mycontainer.Controls)
        {
            Label label = control as Label;
            if (label != null) label.Text = "Found it!";
        }
    }

That should work.
Please notice that if you attach any other logic to your page, you might want to do that in the PreRender event, instead of the Page_Load.

Hope it helps.

Posted 18-Apr-12 11:56am

Leonardo Paneque

Comments

anjumnavid 19-Apr-12 8:49am

Thanks For the response . I found the Solution .

<asp:Content runat="server" id="leftcontent" ContentPlaceHolderID="LeftSidePanel">
<div id="mydiv" runat="server" >
<asp:LinkButton id="Lnk_Heading1" runat="server">
<asp:Label id="lbl_Date1" runat="server" >
<asp:Label id="lbl_Detail1" runat="server" >

<asp:Button ID="Button1" runat="server" Text="Button" />
</div>

Vb.net *******

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim lbl_Date As New Label
Dim i as int16
i = 20
While (i < i + 1)
lbl_Date = TryCast(Mydiv.FindControl("lbl_Date" + i.ToString), Label)
lbl_Date = "Value"
i = i + 1
End While
End Sub

Problem was , I didn't Used DIV in my aspx page . When i put my code in div and use the reference of the div then it work.

Solution 4

XML

<asp:content runat="server" id="leftcontent" contentplaceholderid="LeftSidePanel" xmlns:asp="#unknown">
    <div id="mydiv"  runat="server">
    <asp:linkbutton id="Lnk_Heading1" runat="server"> </asp:linkbutton>
    <asp:label id="lbl_Date1" runat="server"> </asp:label>
    <asp:label id="lbl_Detail1" runat="server"> </asp:label>
    <asp:button id="Button1" runat="server" text="Button" />
    </div>
    </asp:content>

VB

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
   Dim lbl_Date As New Label
   Dim i as int16 i = 20
   While (i < i + 1) lbl_Date = TryCast(Mydiv.FindControl("lbl_Date" + i.ToString), Label)
   lbl_Date = "Value"
   i = i + 1
   End While
   End Sub

Problem was , I didn't Used DIV in my aspx page . When i put my code in div and use the reference of the div in codebehind then it work.

Posted 19-Apr-12 4:26am

anjumnavid

Solution 3

Is it web application or not

if yes
try to put
On formload event
if(!ispostback)
{
put your code
}

Posted 19-Apr-12 3:11am

Pradhan Gagan

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

anjumnavid · Accepted Answer · 2012-04-19T02:52:00

Thanks For the response . I found the Solution .

ASP.NET

<asp:content runat="server" id="leftcontent" contentplaceholderid="LeftSidePanel" xmlns:asp="#unknown"> 
    <div id="mydiv"  runat="server"> 
    <asp:linkbutton id="Lnk_Heading1" runat="server"> </asp:linkbutton>
    <asp:label id="lbl_Date1" runat="server"> </asp:label>
    <asp:label id="lbl_Detail1" runat="server"> </asp:label>
    <asp:button id="Button1" runat="server" text="Button" /> 
    </div> 
    </asp:content>

Vb.net *******

VB

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load 
   Dim lbl_Date As New Label 
   Dim i as int16 i = 20 
   While (i < i + 1) lbl_Date = TryCast(Mydiv.FindControl("lbl_Date" + i.ToString), Label) 
   lbl_Date = "Value" 
   i = i + 1 
   End While 
   End Sub