Read textBox from dynamically created

Question

I am trying to create a textbox dynamically using a string. and then trying to read on a buttton click.

 <%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="textboxtest.aspx.cs" Inherits="test2.textboxtest" %>
 <asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server">
 </asp:Content>
 <asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
 <div id="TextBoxDiv" runat="server" class="asid box">
 </div>
<asp:Button ID="Button1" runat="server" Text="CreateTextBox" onclick="Button1_Click" />
<asp:Button ID="Button2" runat="server" Text="ReadTextBox" onclick="Button2_Click" />
</asp:Content>

Here is the code behind.

    protected void Button1_Click(object sender, EventArgs e)
    {           
        string finalText = @"<input type=""text"" ID=""T1"" runat=""server"">
                             <asp:TextBox ID=""TB1"" runat=""server""></asp:TextBox>";            
        TextBoxDiv.InnerHtml = finalText;
    }

    protected void Button2_Click(object sender, EventArgs e)
    {          
        TextBox txtAddress2 = (TextBox)Page.FindControl("TB1");  
        foreach (Control c in TextBoxDiv.Controls)
        {
            if (c is TextBox)
            {
                TextBox txt = (TextBox)c;
                string str = txt.Text;
            }
        }
    }

As you can see from the code i have tried to access the textbox using find control and also looping through. but both are failing.

Answer 1

I managed to get it to work, but by only having to create dynamic textboxes in Page_Init event. So every time there is a post back you need to re-create your dynamic controls. You can check online, they say the same thing.

So here is the client side:

     <asp:PlaceHolder runat="server" id="TextBoxesHere" />
            <asp:Button ID="Button1" CssClass="btn btn-primary btn-outline" runat="server" 
                        Text="CreateTextBox" OnClick="Button1_Click" />
            <asp:Button ID="Button2" CssClass="btn btn-primary btn-outline" runat="server" 
                        Text="ReadTextBox" OnClick="Button2_Click" />

Server Side:

  protected void Page_Init(object sender, EventArgs e)
    {
        TextBox txt = new TextBox();
        txt.ID = "T1";
        txt.CssClass = "form-control";
        TextBoxesHere.Controls.Add(txt);
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        TextBox txt = new TextBox();
        txt.ID = "T1";
        txt.CssClass = "form-control";
        TextBoxesHere.Controls.Add(txt);
    }

    protected void Button2_Click(object sender, EventArgs e)
    {
        TextBox txt = (TextBox)TextBoxesHere.FindControl("T1");
        ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "", "alert('" + txt.Text + "');", true);

    }

Answer 2

use a Placeholder instead of a div (it will generate a div) and then add controls in the placeholder instead of using InnerHtml.

So this can be achieved like this:

<%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="textboxtest.aspx.cs" Inherits="test2.textboxtest" %>
<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="server"></asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">
    <asp:PlaceHolder runat="server" ID="TextBoxPlaceHolder"></asp:PlaceHolder>
    <asp:Button ID="Button1" runat="server" Text="CreateTextBox" onclick="Button1_Click" />
    <asp:Button ID="Button2" runat="server" Text="ReadTextBox" onclick="Button2_Click" />
</asp:Content>

Code-behind:

protected void Button1_Click(object sender, EventArgs e)
{           
    string finalText = @"<input type=""text"" ID=""T1"" runat=""server"">"; 
    var textbox = new TextBox();
    textbox.ID = "TB1";
    this.TextBoxPlaceHolder.Controls.Add(new LiteralControl(finalText));
    this.TextBoxPlaceHolder.Controls.Add(textbox);
}

protected void Button2_Click(object sender, EventArgs e)
{          
    TextBox txtAddress2 = (TextBox)Page.FindControl("TB1");  
    foreach (Control c in TextBoxDiv.Controls)
    {
        if (c is TextBox)
        {
            TextBox txt = (TextBox)c;
            string str = txt.Text;
        }
    }
}