Question

I am creating some dyanamic textbox on a button click event and on another button click i want to fetch data of that textbox using findcontrol method

 public void addDepartmentBtn_Click(object sender, EventArgs e)
    {

        int count = Convert.ToInt32(countTxtBx.Text);
        lblErrorMsg.Text = "";
        if (Convert.ToInt32(countTxtBx.Text) <= 5)
        {

            for (int i = 0; i < count; i++)
            {
                Label lb = new Label();
                TextBox tb = new TextBox();

                tb.ID = "Textbox_" + i;
                lb.ID = "Label_" + i;
                lb.Text = "Enter Departnment Name: " + Convert.ToInt32(i + 1);
                pnlMain.Controls.Add(new LiteralControl("<br>"));
                pnlMain.Controls.Add(lb);
                pnlMain.Controls.Add(new LiteralControl("&nbsp&nbsp"));
                pnlMain.Controls.Add(tb);
                pnlMain.Controls.Add(new LiteralControl("<br><br>"));
                lblErrorMsg.Text = Convert.ToInt32(i + 1) + "  Departments Created Successfully";
                //string str = string.Empty;
                //TextBox myTB = (TextBox)pnlMain.FindControl("Textbox_" + i);
                //str = myTB.Text;
                //Response.Write(str);

            }

        }
        else
        {
            lblErrorMsg.Text = "You cannot create more than 5 Departments at once:";
        }
    }

On button2 click:

   protected void Button2_Click(object sender, EventArgs e)
        {
            string alltextdata = null;
            for (int i = 0; i < 5; i++)
            {
                Control controltxt = FindControl("Textbox_"+i);
                if (controltxt != null)
                {
                    TextBox txttemp = (TextBox)controltxt;
                    alltextdata = txttemp.Text;

                }
            }

        }

but my find control method alway show me null i check my html page view source which show me every thing correct my textbox name and id is “Textbox_0”,Textbox_1 etc

am i doing some mistake ? please help

Answer 1

When you add the control dynamically, it is not added to the control tree after a postback (the button2 postback). You need to add it again in the Page_Load event in any postback after addDepartmentBtn was clicked.

Save that button was clicked in the ViewState and check it in Page_Load:

public void addDepartmentBtn_Click(object sender, EventArgs e)
    {
        ViewState["addDepartmentBtn_Clicked"] = true;
        AddTextBoxes();
    }

protected void Page_Load(object sender, EventArgs e)
{
    if (Convert.ToBoolean(ViewState["addDepartmentBtn_Clicked"]) == true)
        AddTextBoxes();
}

public void AddTextBoxes()
{
int count = Convert.ToInt32(countTxtBx.Text);
        lblErrorMsg.Text = "";
        if (Convert.ToInt32(countTxtBx.Text) <= 5)
        {

            for (int i = 0; i < count; i++)
            {
                Label lb = new Label();
                TextBox tb = new TextBox();

                tb.ID = "Textbox_" + i;
                lb.ID = "Label_" + i;
                lb.Text = "Enter Departnment Name: " + Convert.ToInt32(i + 1);
                pnlMain.Controls.Add(new LiteralControl("<br>"));
                pnlMain.Controls.Add(lb);
                pnlMain.Controls.Add(new LiteralControl("&nbsp&nbsp"));
                pnlMain.Controls.Add(tb);
                pnlMain.Controls.Add(new LiteralControl("<br><br>"));
                lblErrorMsg.Text = Convert.ToInt32(i + 1) + "  Departments Created Successfully";
                //string str = string.Empty;
                //TextBox myTB = (TextBox)pnlMain.FindControl("Textbox_" + i);
                //str = myTB.Text;
                //Response.Write(str);

            }

        }
        else
        {
            lblErrorMsg.Text = "You cannot create more than 5 Departments at once:";
        }
}