Create Dynamic Textbox and Get values

Question

Hello,
 
I want to create dynamic text box when user click on Add more link button.
For this I am using this code. And I have to mention that I am using master page.
 

protected void lnkAddMore_Click(object sender, EventArgs e)
    {
        if (Request.Cookies["value"] != null)
        {
            i = Convert.ToInt32(Request.Cookies["value"].Value) + 1 ;
        }
        for (int k = 1; k <= i; k++)
        {
            LiteralControl literal = new LiteralControl();
            literal.Text = "<br /><br />";
            Label newLabel = new Label();
            newLabel.Text = "Choice" + " " + k.ToString();
            newLabel.ID = "lblChoice_" + k.ToString();
            newLabel.Attributes.Add("runat", "Server");
            this.panelLabel.Controls.Add(newLabel);
            this.panelLabel.Controls.Add(literal);
       
            LiteralControl literal1 = new LiteralControl();
            literal1.Text = "<br /><br />";
            TextBox nexText = new TextBox();
            nexText.ID = "txtChoice_" + k.ToString();
            nexText.Attributes.Add("TextMode", "MultiLine");
            nexText.Attributes.Add("runat", "Server");
            panelTextbox.Controls.Add(nexText);
            this.panelTextbox.Controls.Add(literal1);
 
            Response.Cookies["value"].Value = i.ToString();
            Session["Panel"] = panelTextbox;
        }
    }
 
protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
          if (Session["Panel"] != null)
                {
                    ContentPlaceHolder content=new ContentPlaceHolder();
                    content.Controls.Add(Session["Panel"] as Panel);
                }
        }
    }
 
Now I am facing trouble how to retrieve the data of the these text boxes after the clicking on the submit button so that I can store the values of there text boxes to database.
 
What will be code written for the click event of btnSave
protected void btnSave_Click(object sender, EventArgs e)
    {
      if (Session["Panel"] != null)
        {
            ContentPlaceHolder content_new = new ContentPlaceHolder();
            for (int i = 1; i <= count; i++)
            {
                strControlName = "txtChoice_" + i.ToString();
 
                TextBox objTextBox = (TextBox)content_new.FindControl(strControlName);
 
                strTextBoxValues[i] = objTextBox.Text;


                string str3 = strTextBoxValues[2];
            }
        }
    }
 

This code is showing error for objTextBox
The error is NullReferenceException
 
And How to write stored procedure for saving data of above code.
 
The main problem is handling the parameter declaration
 
how to declare dynamic parameter for passing values so that value is saved for dynamic textbox
 

Main thing I need is the stored procedure to store the data in the database 

Thanks in advance
 
Deepak Pandey