Can not access text of dynamically created textbox after button click

Question

I have a problem. I have an aspx page with one ContentPlaceHolder. In that ContentPlaceHolder i have one div and one button, like following:

<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">    
    <div id="divCustomCustomers" runat="server" >
    </div>
    <asp:Button runat="server" ID="btnInsert" Text="Insert" OnClick="btnInsert_OnClick" />    
</asp:Content>

On the PageLoad i am dynamically adding a textbox control to the divCustomCustomers like following:

private void AddControls(string currentCustomer)
{
    var customTable = new Table();
    customTable.ID = "tableCustomCustomer_" + currentCustomer;

    var customTrHeaders = new TableRow();
    customTrHeaders.Cells.Add(new TableCell() { Text = "TextId" });

    customTable.Controls.Add(customTrHeaders);

    var customTableCells = new TableRow();

    var tableCellTextId = new TableCell();
    var textBoxTextId = new TextBox() { ID = "tbTextId_" + currentCustomer };
    tableCellTextId.Controls.Add(textBoxTextId);

    customTableCells.Cells.Add(tableCellTextId);

    customTable.Controls.Add(customTableCells);

    divCustomCustomers.Controls.Add(customTable);
}

Then i enter some random text in that textbox (var textBoxTextId = new TextBox() { ID = "tbTextId_" + currentCustomer };).

When i then click my button and call the funtcion btnInsert_OnClick, i can not seem to get the text of the textbox. And after the postback the textbox has dissappeared. I have tried to fetch the textbox in following ways:

    protected void btnInsert_OnClick(object sender, EventArgs e)
    {
        string currentCustomer = "sameCustomerAsWhenCreated";

        var control = divCustomCustomers.FindControl("tbTextId_" + currentCustomer) as TextBox;
        var control2 = divCustomCustomers.FindControl("ContentPlaceHolder1_tbTextId_" + currentCustomer) as TextBox;
        var control3 = this.FindControl("tbTextId_" + currentCustomer) as TextBox;
        var control4 = this.FindControl("ContentPlaceHolder1_tbTextId_" + currentCustomer) as TextBox;
    }

I have also tried to use a FindControl method i read about:

    protected void btnInsert_OnClick(object sender, EventArgs e)
    {
        string currentCustomer = "sameCustomerAsWhenCreated";

        var control = FindControl(this.Controls, "tbTextId_" + currentCustomer);
    }

    private Control FindControl(ControlCollection controlCollection, string name)
    {
        foreach (Control control in controlCollection)
        {
            if (control.ID.ToLower() == name.ToLower() || control.ClientID.ToLower() == name.ToLower())
            {
                return control;
            }

            if (control.Controls.Count > 0)
            {
                Control result = FindControl(control.Controls, name);
                if (result != null)
                {
                    return result;
                }
            }
        }

        return null;
    }

But nothing works, i can not get the control and use the text. Can you guys help me? Please!

Answer 1

Have you run AddControls() if not post back?

Always run AddControls() in page load, And you should get the text from textbox.

I add a Literal in aspx, and following is the code in my aspx.cs

<div id="divCustomCustomers" runat="server" >
</div>
<asp:Button runat="server" ID="btnInsert" Text="Insert" OnClick="btnInsert_Click" />   
<hr />
<asp:Literal ID="ltResult" runat="server"></asp:Literal>


protected void Page_Load(object sender, EventArgs e)
{
    //Don't run AddControls only in first load.
    //if (this.IsPostBack)
    //{
    //    AddControls("sameCustomerAsWhenCreated");
    //}

    AddControls("sameCustomerAsWhenCreated");
}

protected void btnInsert_Click(object sender, EventArgs e)
{
    string currentCustomer = "sameCustomerAsWhenCreated";
    var control = divCustomCustomers.FindControl("tbTextId_" + currentCustomer) as TextBox;

    this.ltResult.Text = "control: " + control.Text + "<br>";
}

Here is my test result