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Hi.

I`m building a small CMS, and want to add the possibility to include server
side code inside static html-strings that is stored in a database.

For e.g. in the string "<div><b>News></b><br>[Controls/News.ascx]</div>",
[Controls/News.ascx] should be replaced by the rendered html-outpu from a
usercontrol that prints out database content. I use regex to get the content
of the []-tags, and load the control and get the output-html with the
following code:

/// <param name="html">Static html from database whith [] tags containg
usercontrols to render</param>
private string renderIncludes(string html )
{
string pattern = @"(\[.*\])";
Match m = Regex.Match(html, pattern, RegexOptions.IgnoreCase);
if (m.Success)
{
for(int i = 0; i < m.Groups.Count; i++)
{
string search = m.Groups[i].Value;
string control = search.Replace("[","").Replace("]","");
Control c = LoadControl(control);
c.DataBind();
string _html = renderControl(c);
html = html.Replace(search, _html);
}
}
return html;
}

private string renderControl(Control ctrl)
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
System.IO.StringWriter tw = new System.IO.StringWriter(sb);
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
ctrl.RenderControl(hw);
return sb.ToString();
}

This works well for usercontrols with text ouput only (e.g. usercontrols
with Repeaters), but when it comes to usercontrols with input a TextBox (e.g
a contact form), I get the following exception:

System.Web.HttpException: Control 'Name' of type 'TextBox' must be placed
inside a form tag with runat=server

Source:

ctrl.RenderControl(hw);

Does anybody have a tip on what to do, or how to proceed? Is there another
way of doing what I`m trying to accomplish?

Best regards,
John

John Olsen wrote:
> Hi.
>
> I`m building a small CMS, and want to add the possibility to include server
> side code inside static html-strings that is stored in a database.
>
> For e.g. in the string "<div><b>News></b><br>[Controls/News.ascx]</div>",
> [Controls/News.ascx] should be replaced by the rendered html-outpu from a
> usercontrol that prints out database content. I use regex to get the content
> of the []-tags, and load the control and get the output-html with the
> following code:
>
> /// <param name="html">Static html from database whith [] tags containg
> usercontrols to render</param>
> private string renderIncludes(string html )
> {
> string pattern = @"(\[.*\])";
> Match m = Regex.Match(html, pattern, RegexOptions.IgnoreCase);
> if (m.Success)
> {
> for(int i = 0; i < m.Groups.Count; i++)
> {
> string search = m.Groups[i].Value;
> string control = search.Replace("[","").Replace("]","");
> Control c = LoadControl(control);
> c.DataBind();
> string _html = renderControl(c);
> html = html.Replace(search, _html);
> }
> }
> return html;
> }
>
> private string renderControl(Control ctrl)
> {
> System.Text.StringBuilder sb = new System.Text.StringBuilder();
> System.IO.StringWriter tw = new System.IO.StringWriter(sb);
> System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(tw);
> ctrl.RenderControl(hw);
> return sb.ToString();
> }
>
> This works well for usercontrols with text ouput only (e.g. usercontrols
> with Repeaters), but when it comes to usercontrols with input a TextBox (e.g
> a contact form), I get the following exception:
>
> System.Web.HttpException: Control 'Name' of type 'TextBox' must be placed
> inside a form tag with runat=server
>
> Source:
>
> ctrl.RenderControl(hw);
>
> Does anybody have a tip on what to do, or how to proceed? Is there another
> way of doing what I`m trying to accomplish?
>
> Best regards,
> John
>
>
>

It really means what it says. Somewhere you have to have in your HTML
markup a form with id="something" and runat="server" as attributes.
Only within that are controls like Textbox valid. So in the HTML
surrounding all this dynamic content, add such a form...

--
Craig Deelsnyder
Microsoft MVP - ASP/ASP.NET

But my really problem is that I have <form runat=server> tags in the base
..ASPX page that is supposed to display the html from the database and and
thus the output from possibly any included usercontrols ([News.ascx],
[Contact.ascx])

If I add <form runat..> in the usercontrols, I get an error because when the
rendered output is added to the ASPX page, the results contain two forms...

Any thougts...??

"Craig Deelsnyder" <cdeelsny@NO_SPAM_4_MEyahoo.com> wrote in message
news:...
> John Olsen wrote:
>> Hi.
>>
>> I`m building a small CMS, and want to add the possibility to include
>> server
>> side code inside static html-strings that is stored in a database.
>>
>> For e.g. in the string "<div><b>News></b><br>[Controls/News.ascx]</div>",
>> [Controls/News.ascx] should be replaced by the rendered html-outpu from a
>> usercontrol that prints out database content. I use regex to get the
>> content
>> of the []-tags, and load the control and get the output-html with the
>> following code:
>>
>> /// <param name="html">Static html from database whith [] tags containg
>> usercontrols to render</param>
>> private string renderIncludes(string html )
>> {
>> string pattern = @"(\[.*\])";
>> Match m = Regex.Match(html, pattern, RegexOptions.IgnoreCase);
>> if (m.Success)
>> {
>> for(int i = 0; i < m.Groups.Count; i++)
>> {
>> string search = m.Groups[i].Value;
>> string control = search.Replace("[","").Replace("]","");
>> Control c = LoadControl(control);
>> c.DataBind();
>> string _html = renderControl(c);
>> html = html.Replace(search, _html);
>> }
>> }
>> return html;
>> }
>>
>> private string renderControl(Control ctrl)
>> {
>> System.Text.StringBuilder sb = new System.Text.StringBuilder();
>> System.IO.StringWriter tw = new System.IO.StringWriter(sb);
>> System.Web.UI.HtmlTextWriter hw = new
>> System.Web.UI.HtmlTextWriter(tw);
>> ctrl.RenderControl(hw);
>> return sb.ToString();
>> }
>>
>> This works well for usercontrols with text ouput only (e.g. usercontrols
>> with Repeaters), but when it comes to usercontrols with input a TextBox
>> (e.g
>> a contact form), I get the following exception:
>>
>> System.Web.HttpException: Control 'Name' of type 'TextBox' must be placed
>> inside a form tag with runat=server
>>
>> Source:
>>
>> ctrl.RenderControl(hw);
>>
>> Does anybody have a tip on what to do, or how to proceed? Is there
>> another
>> way of doing what I`m trying to accomplish?
>>
>> Best regards,
>> John
>>
>>
>>
>
> It really means what it says. Somewhere you have to have in your HTML
> markup a form with id="something" and runat="server" as attributes. Only
> within that are controls like Textbox valid. So in the HTML surrounding
> all this dynamic content, add such a form...
>
> --
> Craig Deelsnyder
> Microsoft MVP - ASP/ASP.NET

[hellocrowley]

I have exactly the same problem too. Can anyone help?

[chrisajohn]

OK - this isn't perfect, but here is how I got around it.

First a created a "dummy" user control (lets call it UCDummy) that only contained the form tag and the control I "really" wanted to render the output of.

The reason I did this is because sometimes I use the "real" usercontrol on my website and if I were to keep the form tag on it, it would give me an error saying there are too many form tags on the page.

For example - this code is within the "dummy" user control:

<asp:form runat="server">
... THE USER CONTROL HERE
</asp:form>

Then on the page where I want to render the html (in my case I put it in the database for later use), I do the following:

StringBuilder SB = new StringBuilder();
StringWriter SW = new StringWriter(SB);
HtmlTextWriter htmlTW = new HtmlTextWriter(SW);
UCDummy.Visible = true;
UCDummy.RenderControl(htmlTW);
WhereEverIWantItToGo = SB.ToString();
UCDummy.Visible = false;

Now I have the best of both worlds. It does necessitate an extra file, but sometimes it doesn't need to be pretty, it just needs to work.

Hope this helps!

[shailendrasinh]

Hi John, I have also the same problem in my cms. But the thing is I have a NewsLetter control and I am tring to render it in html. It gives the error and if I put <form runat="server"> again in control, it says duplicate form tags.

One more issue, is I get html rendered but I have server side event in that control which is not executed from the page when I render the control.

Please let me know If you have found any solution for this.