CODEWITHSUNDEEP
c#.netasp.net
Aaron
Aaron

Reputation: 464

GetElementsByTagName functionality from .net code-behind page?

I am writing a webpage in C# .NET. In javascript there is a function called GetElementsByTagName... this is nice for javascript invoked from the .aspx page. My question is, is there any way I can have this kind of functionality from my C# code-behind?

--

The scenario for those curious: I used an asp:repeater to generate a lot of buttons, and now I'm essentially trying to make a button that clicks them all. I tried storing all the buttons in a list as I created them, but the list is getting cleared during every postback, so I thought I could try the above method.

Upvotes: 1

Views: 2971

Answers (7)

StingyJack
StingyJack

Reputation: 19489

FindControl(), or iterate through the controls on the page...

For each ctl as Control in Me.Controls
  If ctl.Name = whatYouWant Then
    do stuff
Next 'ctl

--If you are creating the controls, you should be setting their ID's 

Dim ctl as New Control()
ctl.ID = "blah1"

etc...

Upvotes: 2

cllpse
cllpse

Reputation: 21727

Or a variation of my own code, only changing the ASPX.CS:

using System;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Collections.Generic;


public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(Object sender, EventArgs e)
    {
        #region Fill Repeater1 with some dummy data
        DataTable dt = new DataTable();

        dt.Columns.Add(new DataColumn("column"));

        DataRow dr = null;

        for (Int32 i = 0; i < 10; i++)
        {
            dr = dt.NewRow();

            dr["column"] = "";

            dt.Rows.Add(dr);
        }

        this.Repeater1.DataSource = dt;
        this.Repeater1.DataBind();
        #endregion


        foreach (Button b in this.FindButtonsInRepeater(ref this.Repeater1))
        {
            b.Text = "I was found and changed";
        }
    }


    private List<Button> FindButtonsInRepeater(ref Repeater repeater)
    {
        List<Button> buttonsFound = new List<Button>();


        foreach (RepeaterItem ri in repeater.Controls)
        {
            foreach (Control c in ri.Controls)
            {
                try
                {
                    buttonsFound.Add((Button)c);
                }

                catch (Exception exc)
                {
                }
            }
        }


        return buttonsFound;
    }
}

Upvotes: 0

cllpse
cllpse

Reputation: 21727

ASPX:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
    <head runat="server">
        <title>Untitled Page</title>
    </head>

    <body>
        <form id="form1" runat="server">
            <asp:Repeater runat="server" ID="Repeater1">
                <ItemTemplate>
                    <asp:Button runat="server" ID="Button1" Text="I was NOT changed" />
                </ItemTemplate>
            </asp:Repeater>
        </form>
    </body>
</html>

ASPX.CS:

using System;
using System.Data;
using System.Web.UI;
using System.Web.UI.WebControls;


public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(Object sender, EventArgs e)
    {
        DataTable dt = new DataTable();

        dt.Columns.Add(new DataColumn("column"));

        DataRow dr = null;

        for (Int32 i = 0; i < 10; i++)
        {
            dr = dt.NewRow();

            dr["column"] = "";

            dt.Rows.Add(dr);
        }

        this.Repeater1.DataSource = dt;
        this.Repeater1.DataBind();


        foreach (RepeaterItem ri in this.Repeater1.Controls)
        {
            foreach (Control c in ri.Controls)
            {
                Button b = new Button();


                try
                {
                    b = (Button)c;
                }

                catch (Exception exc)
                {
                }


                b.Text = "I was found and changed";
            }
        }
    }
}

Upvotes: 0

Joel Coehoorn
Joel Coehoorn

Reputation: 416149

Whenever you do any postback, everything is recreated, including your databound controls.

If your list is gone, so are the button controls. Unless, of course, you've recreated them, and in that case you should have recreated the list as well.

Upvotes: 0

stephenbayer
stephenbayer

Reputation: 12431

I don't know exactly what you mean by clicks them all. But how would this following code work for you? I don't know, I haven't tested... 

protected void Page_Load(object sender, EventArgs e)
{

    foreach (Control control in GetControlsByType(this, typeof(TextBox)))
    { 
        //Do something?
    }

}
public static System.Collections.Generic.List<Control> GetControlsByType(Control ctrl, Type t)
{
    System.Collections.Generic.List<Control> cntrls = new System.Collections.Generic.List<Control>();


    foreach (Control child in ctrl.Controls)
    {
        if (t == child.GetType())
            cntrls.Add(child);
        cntrls.AddRange(GetControlsByType(child, t));
    }
    return cntrls;
}

Upvotes: 0

devlord
devlord

Reputation: 4164

Try this:

foreach (Control ctl in myRepeater.Controls)
{ 
  if (ctl is Button)
  {
    ((Button)ctl).Click();
  }
}

HTH...

Upvotes: 3

Dana
Dana

Reputation: 32997

Well, you can find controls with the page's FindControl method, but Repeater elements have names generated by .net.

As an aside, if you really want to, you could store the list of buttons in your page's ViewState (or perhaps a list of their names).

Upvotes: 1

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