Parser Error in IFrame When added in Application Page

Question

I am creating a SharePoint-2013 web-part in that I have created Application Page.

In that page I am using <iframe> element only there are no any other elements just for testing. But it is giving me error like:

Server Error in '/' Application.
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.

Parser Error Message: The base class includes the field 'frame1', but its type (System.Web.UI.HtmlControls.HtmlIframe) is not compatible with the type of control (System.Web.UI.HtmlControls.HtmlGenericControl).

Source Error:


Line 364:                <tr>
Line 365:                    <td>
Line 366:                        <iframe id="frame1" frameborder="0" runat="server" scrolling="no" width="100%" height="200px" style="margin: 0px; padding: 0px;" visible="false"></iframe>
Line 367:                    </td>
Line 368:                </tr>


Source File: /_layouts/15/OpportunityViewWP/MasterPage.aspx    Line: 366

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.17929 

Below is the screenshot.

But when I am adding the same <iframe> in Visual-Web-Part it works properly.

Can anyone help me to solve this problem.?

Thanks in advance...!!

Answer 1

Go to your .cs designer file.

Change:
protected global::System.Web.UI.HtmlControls.HtmlGenericControl FinalScoreframe;
To:
protected global::System.Web.UI.HtmlControls.HtmlIframe FinalScoreframe;

Will solve your problem. :)

Answer 2

Change

<compilation targetFramework="4.0"/>

to

<compilation targetFramework="4.5"/>