Get Rendered HTML from User Control

Question

User800858375 posted

Hi everyone,

It is possible to grab the HTML output from a custom control by doing the following:

StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
HtmlTextWriter htmlTw = new HtmlTextWriter(sw);

myCustomControl.RenderControl(htmlTw);

string controlsHTML = sb.ToString(); 

I was wondering how you could do the same of a User control and its entire contents. Take an example that a user control contains some standard HTML markup as well as a GridView control and a Button control. The GridView would normally be data bound in the Page_Load event.

If you use LoadControl("target.ascx") and grab the rendered contents:

A > Only the standard HTML markup is retrieved
B > The GridView does not get data bound

How can you bind the grid view, and then retrieve the entire contents of the user control?

 Thanks again,
Ad 

Answer 1

User800858375 posted

Hi again,

I answered my own question. the solution is actually pretty obvious. You have to simply override the Rendercontrol method within the user control:

public override void RenderControl(HtmlTextWriter writer)
{
    GridView.DataSource = myDataSource;
    GridView.DataBind();

    base.RenderControl(writer);
}

 

Answer 2

User1508857181 posted

When I try with following code in load event of page

======== 

Dim uc As Control = Page.LoadControl("dg.ascx")
PlaceHolder1.Controls.Add(uc)Dim sb As New StringBuilder
Dim sw As New IO.StringWriter(sb)
Dim hw As New HtmlTextWriter(sw)

uc.RenderControl(hw)

Dim controlsHTML As String = sb.ToString()

 ==========

I get error : Control 'ctl02_GridView1' of type 'GridView' must be placed inside a form tag with runat=server.

where GridView1 is a gridview control placed in dg.ascx.

Any ideas?

-Pinal Bhatt