how to create dynami controls on button click ?

gavriel ankri

12y1.6k.NET

hello

I created a form with 3 textbox and I want to add another dynamic text box when the user click the button;

Everything working fine, but when I try to read the data using FindControl it doesnt find anything.

If I create the dynamic buttons on Page_Init, its find them, but if I create then on the button click event it wont find them using FindControl.

what can I do ?

8 Replies

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Vulpes11y ago
Accepted answer
I see what you mean.

It appears that the ViewState variable is not refreshed until AFTER the page has loaded.

I'm cheating a bit but this is working OK for me without the need to click the MoreBtn twice:

protected void Page_Load(object sender, EventArgs e)
{

if (!IsPostBack)
{
ViewState["num"] = 1; // start at 1 rather than 0
Panel1.Style["Position"] = "Relative";
}
else
{
int num = int.Parse(ViewState["num"].ToString());
if (num > 0)
{
generateDynamicControls(num);
}
}

}
protected void MoreBtn_Click(object sender, EventArgs e)
{
int num = int.Parse(ViewState["num"].ToString());
num++; // this won't take effect until the postback after next
ViewState["num"] = num.ToString();
}

protected void generateDynamicControls(int num)
{
for (int i = 1; i <= num; i++)
{
TextBox newtxt = new TextBox();
newtxt.Style["Position"] = "Absolute";
newtxt.Style["Top"] = ((i -1) * 25).ToString() + "px";
newtxt.Style["Left"] = "10px";
newtxt.ID = "newtxt" + i;
newtxt.Text = newtxt.ID;
Panel1.Controls.Add(newtxt);
}
}
gavriel ankri11y ago
wow!
you did it!
Great. you are the best
gavriel ankri11y ago
void Page_Load(object sender, EventArgs e)
{
if (int.Parse(ViewState["num"].ToString()) > 0)
{

generateDynamicControls();
}
}

void MoreBtn_Click(object sender, EventArgs e)
{
num = int.Parse(ViewState["num"].ToString());
num += 1;
ViewState["num"] = num.ToString();
}

void generateDynamicControls()
{
TextBox newtxt = new TextBox();
newtxt.ID = "newtxt" + num;
panel2.Controls.Add(newtxt);

}
Vulpes11y ago
Can you post the code as you now have it, please.
gavriel ankri11y ago
thank you
but if I create them on page_load, its only fire on the second click, but not in the first click.
do you know how can it work on the first click ?
Vulpes11y ago
Dynamically created controls don't persist on a post-back which is why you can't find them.

You can't therefore create them on a button click.

You either need to create them in Page_Init or each time the page loads in Page_Load.
gavriel ankri11y ago
void MoreBtn_Click(object sender, EventArgs e)
{

for (int i = guestList.Count; i < guestList.Count; i++)
{

TextBox newtxt = new TextBox();
newtxt.ID = "lbName" + i;

panel2.controls.add (newtxt);
}

this work fine, but when i try to read the data:

el0.SetAttribute("fullName", ((TextBox)FindControl("lbName" + i)).Text;

I get an error that it cant find the specific textbox
Abhay Shanker11y ago
can you please share the code and point where you are getting error