CODEWITHSUNDEEP
c#asp.net
Evgeny Sdvizhkov
Evgeny Sdvizhkov

Reputation: 61

Dynamically created textbox c#

I create textbox dynamically, but can't retrieve a value from created textbox. Anyone can explain to me what am I doing wrong?

HtmlGenericControl testes = new HtmlGenericControl("DIV");
    testes.ID = "Div_Cabos_Rede";
    testes.Attributes.Add("class", "col-md-12 letra");
    testes.InnerHtml = "Cabos de rede";
    TextBox Cabos_de_rede = new TextBox();
    Cabos_de_rede.ID = "Txt_Cabos_Rede";
    Cabos_de_rede.Attributes.Add("class", "col-md-12 form-control");
    testes.InnerHtml = "Cabos de rede";
    Body.Controls.Add(testes);
    Body.Controls.Add(Cabos_de_rede);

This works fine almost fine (minor unrelated css problems), but when later I try to retrieve data from dynamically created textbox I get NULL value.

Here is my code to retrieve value:

 TextBox testar = (TextBox)Body.FindControl("Txt_Cabos_Rede");
 ScriptManager.RegisterStartupScript(this, GetType(), "alert", "alert('" + testar + "');", true);

Upvotes: 1

Views: 175

Answers (1)

Win
Win

Reputation: 62260

The main problem dealing with dynamically created control is you need to reload them back in either Page Init or Page Load event.

FYI: We normally use either Panel or PlaceHolder to load controls instead of Body tag, so that we can style them easily.

ASPX

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="DemoWebForm.Default" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
        <asp:PlaceHolder runat="server" ID="PlaceHolder1" />
        <asp:Button runat="server" ID="SubmitButton" Text="Submit" OnClick="SubmitButton_Click" />
        <br />
        Posted Value:
        <asp:Label runat="server" ID="ResultLabel" />
    </form>
</body>
</html>

Code Behind

public partial class Default : System.Web.UI.Page
{
    protected void Page_Init(object sender, EventArgs e)
    {
        HtmlGenericControl testes = new HtmlGenericControl("DIV");
        testes.ID = "Div_Cabos_Rede";
        testes.Attributes.Add("class", "col-md-12 letra");
        testes.InnerHtml = "Cabos de rede";
        TextBox Cabos_de_rede = new TextBox();
        Cabos_de_rede.ID = "Txt_Cabos_Rede";
        Cabos_de_rede.Attributes.Add("class", "col-md-12 form-control");
        testes.InnerHtml = "Cabos de rede";
        PlaceHolder1.Controls.Add(testes);
        PlaceHolder1.Controls.Add(Cabos_de_rede);
    }

    protected void SubmitButton_Click(object sender, EventArgs e)
    {
        TextBox testar = FindControlRecursive(PlaceHolder1, "Txt_Cabos_Rede") as TextBox;
        ResultLabel.Text = testar.Text;
    }

    // Custom method to search a control recursively 
    // in case it is nested inside other control. 
    // You can create it as an extension method if you would like.
    public static Control FindControlRecursive(Control root, string id)
    {
        if (root.ID == id)
            return root;

        return root.Controls.Cast<Control>()
            .Select(c => FindControlRecursive(c, id))
            .FirstOrDefault(c => c != null);
    }
}

I know you have a lot of questions. Before commenting on this question, please create a new project, and make this very simple code to work.

Upvotes: 1

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