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Text property of a TextBox is empty when an async PostBack occurs

I've had a look at lots of posts and I feel like I'm going crazy as nothing I've tried seems to work. I simply want to click a button and retrieve the value of a textbox.
I'm using web forms with a site.master so not sure if this could be affecting the problem, but most of the solutions I've seen don't appear to be using a site.master.
I'm not binding the textbox, initially I just wanted to create a contact form.
<%# Page Title="About" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="About.aspx.cs" Inherits="Blackburn_Pulse.About" %>
<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
<script>$("#menuAbout").addClass("navi-active");</script>
<div class="contentBody">
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:TextBox ID="tb_Test" EnableViewState="true" CausesValidation="false" runat="server"></asp:TextBox>
<asp:LinkButton ID="btn_Test" runat="server" OnClick="btn_Test_Click" Text="send test" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btn_Test" EventName="click" />
</Triggers>
</asp:UpdatePanel>
</div>
</asp:Content>
public partial class About : Page
{
protected void Page_Load(object sender, EventArgs e)
{
this.Page.Master.EnableViewState = true;
if (IsPostBack)
{
var test_var = tb_Test.Text; //returning empty
}
}
protected void btn_Test_Click(object sender, EventArgs e)
{
var test_var = tb_Test.Text; //returning empty
}
}
UPDATE:
site.master.cs
public partial class SiteMaster : MasterPage
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
BindCategories();
}
}
protected void BindCategories()
{
Categories Categories = new Categories();
rpt_categories.DataSource = Categories.Get_Categories();
rpt_categories.DataBind();
}
protected void lb_newsCat_Command1(object sender, CommandEventArgs e)
{
switch (e.CommandName)
{
case "naviTo":
//Redirect user to selected category
Response.Redirect("~/" + e.CommandArgument.ToString());
break;
}
}
}

I'm converting a PHP website to an ASP.net website. Turns out I had another HTML form tag on a search box that I haven't started working on yet.
Unfortunately the debugger doesn't throw an error if you have another form tag so anybody else who's just spent hours of their lives searching, double check you don't have more than 1 form tag!
In my site.master.aspx file, I had a search box as follows:
<form method="post" action="?">
<input class="form-control mr-sm-2" type="search" placeholder="Search" aria-label="Search">
<button class="btn btn-outline-primary my-2 my-sm-0" type="submit">Search</button>
</form>
Once I took the extra form tag out, everything worked fine.

C# - Transfer the text of a hyperlink through a session inside a repeater

I want to transfer the text of a hyperlink through a session inside a repeater. But I can not think of the logic to do this. My repeater generates links within that dropdown menu and I want to get the text that appears in the link and pass it to another page Sectors.aspx. This is what I have done so far:
--- edit ---
I want that when the link is clicked, the text that is in the link is passed to the other page. For example, the menu has two links, APPLE and BANANA. When the user clicks APPLE, I want the next page Sectors.aspx to know that the user clicked APPLE and not the other options.
ASPX Page:
<asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server">
<div class="dropdown">
<button class="dropbtn">Setor</button>
<div class="dropdown_content">
<asp:Repeater ID="sectors_menu" runat="server">
<ItemTemplate>
<asp:HyperLink id="hyperlink1" NavigateUrl="Sectors.aspx" Text='<%#((System.Data.DataRowView)Container.DataItem)["sector"] %>' runat="server"></asp:HyperLink>
</ItemTemplate>
</asp:Repeater>
</div>
</div>
</asp:Content>
Code Behind
public partial class _Default : System.Web.UI.Page
{
MySqlConnection mysql_connection = new MySqlConnection(ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString);
string mysql_string;
MySqlDataAdapter mysql_data_adapter;
public void Page_Load(object sender, EventArgs e)
{
Sector_label();
}
public void Sector_label()
{
mysql_string = "SELECT * FROM employees GROUP BY sector";
mysql_data_adapter = new MySqlDataAdapter(mysql_string, mysql_connection);
DataTable data_table = new DataTable();
mysql_data_adapter.Fill(data_table);
DataView data_view = new DataView(data_table);
sectors_menu.DataSource = data_view;
sectors_menu.DataBind();
for (int count = 0; count < sectors_menu.Items.Count; count++)
{
var test = (HyperLink)sectors_menu.Items[count].FindControl("hyperlink1");
Session["session_hyperlink"] = test.Text;
// Debug.WriteLine(test.Text);
}
}
}

You could add the text as a parameter of the NavigateUrl:
<ItemTemplate>
<asp:HyperLink id="hyperlink1" NavigateUrl='<%# "Sectors.aspx?sector=" + Server.UrlEncode(((System.Data.DataRowView)Container.DataItem)["sector"]).ToString() %>' Text='<%#((System.Data.DataRowView)Container.DataItem)["sector"] %>' runat="server"></asp:HyperLink>
</ItemTemplate>
Then, Sectors.aspx can retrieve it through the "sector" parameter:
protected void Page_Load(object sender, EventArgs e)
{
string sector = Request.Params["sector"];
}
That id="hyperlink1" parameter looks fishy, though. You don't want all your hyperlinks to have the same ID.

Just replace hyperlink tag with this code ,
<asp:HyperLink runat="server" Navigateurl='<%#"Sectors.aspx?mySector="+ Eval("sector") %>'
Text='<%#((System.Data.DataRowView)Container.DataItem)["sector"] %>' />

Retrieving ascx control value from a callback registered on master page. Control added to Repeater's PlaceHolder during OnItemCreated

This is my best attempt to simplify the code to ask the question well. Hopefully it helps.
The short: I need to get the value of a dynamically created Control whose path is loaded from the database and added to a Repeater that contains a PlaceHolder. The value needs to be retrieved from a function on the child page that is called from the master page.
The long:
I have a master page that has a lot of settings on it, and an area where a child page can add its own configuration options. Let's say the master page is as follows:
<%# Master Language="C#" MasterPageFile="~/MainTemplate.master" CodeBehind="ConfigureChoices.master.cs" Inherits="Demo.ConfigureChoices"
AutoEventWireup="true" %>
<asp:Content ID="Content1" ContentPlaceHolderID="RenderArea" runat="Server">
<asp:Panel runat="server" ID="PanelConfiguration">
<asp:TextBox ID="TextBoxForSomething" runat="Server"/>
<asp:DropDownList ID="AnotherConfigurableThing" runat="server" OnSelectedIndexChanged="DropDownConfiguration_Click" AutoPostBack="true">
<asp:ListItem Text="Option 1" Selected="True" Value="1"></asp:ListItem>
<asp:ListItem Text="Option 2" Value="2"></asp:ListItem>
<asp:ListItem Text="Option 3" Value="3"></asp:ListItem>
</asp:DropDownList>
<!--etc-->
<asp:ContentPlaceHolder ID="CustomSettings" runat="server">
</asp:ContentPlaceHolder>
<asp:Button ID="ButtonSubmit" runat="Server" Text="Submit" OnClick="ButtonSubmit_Click" />
</asp:Panel>
</asp:Content>
In codebehind, I need to persist the settings to the database, including custom settings from the user page. The child pages need some of the data created from the master page in order to persist its data. To accomplish this, I have an event that gets populated on child page load and called prior to redirect. It looks like this:
public delegate void BeforeSubmitEventHandler(int configInfoID);
public event BeforeSubmitEventHandler BeforeSubmit;
protected void ButtonSubmit_Click(object sender, EventArgs e)
{
ConfigInfo config = new ConfigInfo;
config.EnteredText = TextBoxForSomething.Text;
config.SelectedValue = AnotherConfigurableThing.SelectedValue;
int configID = AddToDatabase(config);
if (BeforeSubmit != null)
BeforeSubmit(configID);
Response.Redirect("RedirectURL.aspx");
}
The custom section of the user page has a Repeater, a DropDownList, and an "Add" Button. The Repeater has the name of the option, a short description, a delete image, and a PlaceHolder for loading custom controls from the database. More on that after the code:
<%# Page Title="" Language="C#" MasterPageFile="~/ConfigureChoices.master" ValidateRequest="false"
AutoEventWireup="true" Inherits="Demo.CustomChoicePage1" Codebehind="CustomChoicePage1.aspx.cs"
MaintainScrollPositionOnPostback="true" %>
<asp:Content ID="MyContent" ContentPlaceHolderID="CustomSettings" runat="server">
<asp:Repeater ID="RepeaterSelectedOptions" OnItemCreated="OnOptionAdded" runat="server">
<HeaderTemplate>
<table id="SelectedOptionsTable">
<thead>
<tr>
<th>Name</th>
<th>Description</th>
<th>Remove</th>
</tr>
</thead>
<tbody>
</HeaderTemplate>
<ItemTemplate>
<tr>
<td>
<%# Server.HtmlEncode(Eval("Name").ToString()) %>
</td>
<td>
<%# Server.HtmlEncode(Eval("Description").ToString()) %>
</td>
<td>
<asp:ImageButton ImageUrl="delete.png" ID="ImgDeleteOption" runat="server" OnCommand="DeleteOption_Click"
CommandArgument='<%# Eval("OptionID") %>' />
</td>
</tr>
<asp:PlaceHolder runat="server" ID="optionConfiguration" />
</ItemTemplate>
<FooterTemplate>
</tbody>
</table>
</FooterTemplate>
</asp:Repeater>
<br />
<asp:DropDownList ID="DropDownListAvailableOptions" runat="server" />
<asp:Button ID="ButtonAddOption" runat="server" Text="Add Option" OnCommand="AddOption_Click" />
</asp:Content>
In codebehind, the Repeater is populated the first time on Page_Load using the following code (combination of C# and pseudocode to shorten this already-long question):
protected void Page_Load(object sender, EventArgs e)
{
((ConfigureChoices)Master).BeforeSubmit += OnSubmit;
if (!Page.IsPostBack)
{
RefreshOptions();
}
}
protected void RefreshOptions()
{
List<Option> fullList = GetOptionsFromDB();
List<Option> availableList = new List<Option>();
List<Option> selectedList = new List<Option>();
List<int> selectedOptions = GetSelectedOptions();
// Logic here to set the available/selected Lists
DropDownListAvailableOptions.DataSource = availableList;
DropDownListAvailableOptions.DataBind();
RepeaterSelectedOptions.DataSource = selectedList;
RepeaterSelectedOptions.DataBind();
}
public List<short> GetSelectedOptions()
{
List<int> selectedOptions = this.ViewState["SelectedOptions"];
if (selectedOptions == null)
{
selectedOptions = new List<int>();
foreach (Option option in GetOptionsFromDB())
{
selectedOptions.Add(option.OptionID);
}
}
return selectedOptions;
}
If the add or remove buttons are clicked, the following methods are used:
public void AddOption_Click(object sender, CommandEventArgs e)
{
List<int> selectedOptions = GetSelectedOptions();
selectedOptions.Add(Convert.ToInt32(DropDownListAvailableOptions.SelectedValue));
this.ViewState["SelectedOptions"] = selectedTests;
RefreshOptions();
}
public void DeleteOption_Click(object sender, CommandEventArgs e)
{
List<int> selectedOptions = GetSelectedOptions();
selectedOptions.Remove(Convert.ToInt32(e.CommandArgument));
this.ViewState["SelectedOptions"] = selectedOptions;
RefreshOptions();
}
Finally, the meat of where I think the issue might be, and some explanation of what I've tried. When an option is added to the control, a different table is queried to see if there's an additional ascx that must be loaded into the placeholder. This happens in the method pointed to by OnItemCreated in the Repeater:
protected void OnOptionAdded(Object sender, RepeaterItemEventArgs e)
{
if (e.Item == null || e.Item.DataItem == null)
return;
short optionID = ((Option)e.Item.DataItem).OptionID;
OptionControl optionControl = GetControlForOptionFromDB(optionID);
if (optionControl == null)
return;
CustomOptionControl control = (CustomOptionControl)this.LoadControl(optionControl.Path);
control.ID = "CustomControl" + optionID.ToString();
TableRow tableRow = new TableRow();
tableRow.ID = "CustomControlTR" + optionID.ToString();
tableRow.CssClass = "TestConfiguration";
TableCell tableCell = new TableCell();
tableCell.ID = "CustomControlTC" + optionID.ToString();
tableCell.ColumnSpan = 3;
e.Item.FindControl("optionConfiguration").Controls.Add(tableRow);
tableRow.Cells.Add(tableCell);
tableCell.Controls.Add(control);
}
So all of the above "works" in that I see the control on the page, the lists work correctly, and stuff like that. When I click the "Submit" button, I see the configuration (for the sake of this example, let's just say it's a single checkbox) in the Request form variable. However, setting a breakpoint in my callback method on the child page, the CustomOptionControl does not appear to be in the RepeaterSelectedOptions. Only the Option is present.
I have tried at least the following, and more (but I honestly can't recall every step I've tried):
adding a call to RefreshOptions to an overridden LoadViewState
after the call to load the base
doing my initial Repeater binding
in Page_Init instead of Page_Load
different orders of adding the table row, cell, and custom controls to each other and the main
page
How should I be structuring this page and its necessary databinding events so that I can make something like the commented lines in the following code work? When I break at the start of the method and look through the RepeaterOptions.Controls, the CustomOptionControls are gone.
protected void OnSubmit(int configID)
{
//List<CustomOptionControl> optionsToInsert = find CustomOptionControls in RepeaterOptions (probably an iterative search through the Controls);
//foreach (CustomOptionControl control in optionsToInsert)
//{
// control.AddOptionToDatabase(configID);
//}
}

I'm not sure what changed, maybe it was taking the break to rubber duck debug using all of the above. I've gone back and tried tweaking some of the things I had before (order of insertion, which call to use, etc) to see if they make a difference, but either way, the Control is now being persisted in the ViewState properly with the above code. It is available on postback from the master page call so long as the following is added (bullet #1 of what I tried before):
protected override void LoadViewState(object savedState)
{
base.LoadViewState(savedState);
RefreshOptions();
}
Earlier, savedState was only showing the List<int> added to it to maintain selected options. At some point in tweaking and debugging, I saw that the controls I created were now in the viewstate, and adding a RefreshOptions call worked. This means on postback for add/remove there are two calls to RefreshOptions, but I can either work around that or ignore it, since behavior is still correct. Thanks for looking!

ASP.NET Button OnClick within Repeater and LoginView

I'm developing a ASP.NET website with a C# backend. I'm having a problem with how to set an onclick event for buttons that are nested inside of both a loginview and a repeater. The code works fine for displaying all of the other data (anonymous view displays only an error message) but right now the buttons just redirect to the same page and remove the repeater and all contents, whereas they're supposed to run a specific delete function. The repeater, as it is right now, uses an alternatingitem template. If I remove the buttons from the nested controls, they work. I've tried this with buttons, linkbuttons, and imagebuttons. I'd rather use the latter, if possible. Is it possible to assign an Onclick to these buttons if they're nested like this? If not, what approach should I use?
<asp:LoginView ID="LoginLinksView" runat="server" EnableViewState="false">
<AnonymousTemplate>
<asp:Label ID="errorlabel" runat="server"></asp:Label>
</AnonymousTemplate>
<LoggedInTemplate>
<asp:Repeater id="Repeater" runat="server" >
<HeaderTemplate>
<table cellspacing="0" cellpadding="0">
<thead></thead>
</HeaderTemplate>
<ItemTemplate>
<tr class="Repeaterrow">
<!--Additional code here-->
<asp:ImageButton ID="delbutton" runat="server" ImageUrl=
"~/Images/delete.png" Onclick="DeleteOnClick"/>
</tr>
</ItemTemplate>
<AlternatingItemTemplate>
<tr class="Repeaterrow">
<!--Additional code here-->
<asp:ImageButton ID="delbutton" runat="server" ImageUrl=
"~/Images/delete.png" Onclick="DeleteOnClick"/>
</tr>
</AlternatingItemTemplate>
<FooterTemplate>
</table>
</FooterTemplate>
</asp:Repeater>
</LoggedInTemplate>
</asp:LoginView>

Here are the problems with your approach
1- The button issues postback as it should. But you need to put some CommandArgument with to identify "key" or which row you are processing it for.
2- Re Bind your Repeater with source. Below is the sample code for you.
protected void Page_Load(object sender, EventArgs e)
{
BindRepeater();
}
private void BindRepeater()
{
List<int> items = new List<int>();
for (int i = 0; i < 10; i++)
{
items.Add(i);
}
Repeater.DataSource = items;
Repeater.DataBind();
}
protected void DeleteOnClick(object sender, EventArgs e)
{
ImageButton delbutton = (sender as ImageButton);
//1- call your method with passing in delbutton.CommandArgument - it will give you key/ whatever you like
//2- Rebind the Repeater here and that will bind controls again...
BindRepeater();
}
protected void Repeater_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
ImageButton delbutton = (sender as RepeaterItem).FindControl("delbutton") as ImageButton;
if (delbutton != null)
{
delbutton.CommandArgument = (sender as RepeaterItem).ItemIndex.ToString();
}
}
and ASPX Repeater definition would change to
Thanks,
Riz

ASP.NET Panel FindControl within DataList to change property C#

I'm new to this ASP.NET stuff. In my page I have a Datalist with a FooterTemplate. In the footer I have a couple panels that will be visible depending on the QueryString. The problem I am having is trying to find these panels on Page_Load to change the Visible Property. Is there a way to find this control in the Page_Load? For example this is part of the aspx page:
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<asp:DataList ID="dlRecords" runat="server">
<FooterTemplate>
<asp:Panel ID="pnlArticleHeader" runat="server" Visible="false" >
</asp:Panel>
</FooterTemplate>
</asp:Datalist>
</asp:Content>
Here is something in the codebehind:
protected void Page_Load(object sender, EventArgs e)
{
location = Request.QueryString["location"];
if (location == "HERE")
{
Panel pnlAH = *Need to find control here*;
pnlAH.Visible=true;
}
}
Like I said I am new at this. Everything I have found doesn't seem to work so I decided to post a specific question. Thanks in advance

DataList has event OnItemCreated, overriding allows select type of row:
Panel _pnlArticleHeader;
void Item_Created(Object sender, DataListItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Footer)
{
_pnlArticleHeader =(Panel)e.Item.FindControl("pnlArticleHeader");
}
}
After event invocation in the field: _pnlArticleHeader you will get desired panel. This way is safe since created only once. NOTE! same way for common DataList's row would return only last one.