Controls do not appear on dynamically created user control

Question

I have user control named DateTimeUC which has two textboxes on its markup:

<asp:TextBox ID="dateTextBox" runat="server"></asp:TextBox>
<asp:TextBox ID="timeTextBox" runat="server"></asp:TextBox>

I am dynamically creating this control in another user control:

Controls.Add(GenerateDateTime(parameter));
private DateTimeUC GenerateDateTime(SomeParameter parameter)
{
    DateTimeUC uc = new DateTimeUC();
    uc.ID = parameter.Name;
    return uc;
}

But when I render the page, DateTimeUC renders nothing. I checked it like this:

protected override void Render(HtmlTextWriter writer)
{
    base.Render(writer);

    StringBuilder builder = new StringBuilder();
    StringWriter swriter = new StringWriter(builder);
    HtmlTextWriter hwriter = new HtmlTextWriter(swriter);
    base.Render(hwriter);
    string s = builder.ToString();
}

s is empty and Controls.Count is 0. What am I doing wrong?

Radon

Answer 1

You must use the LoadControl( "your_user_control_app_relative_path.ascx" ) method instead of "DateTimeUC uc = new DateTimeUC();"

Boeke

Been looking for an answer to this all day. Thanks! – Riviera

How can I load a user control that is embedded in a dll? – Lorrinelorry

@Zolomon: You need the .ascx file. The *.ascx file contains the asp.net markup which is used for autogenerated class. The autogenerated class inherits from class in assembly (.dll). – Boeke

Answer 2

I ran into this problem myself a while back. You need to use the LoadControl() method. Check out this page on it.

Goran

Answer 3

I think you want to add your control to the page's form & not the form itself.

your code:

Controls.Add( GenerateDateTime(parameter) );

try:

Page.Form.Controls.Add( GenerateDateTime(parameter) );

Linet