Microsoft.ReportingServices.ReportViewerControl.WebForms version 150.1404.0 returns invalid HTML for Reserved.ReportViewerWebControl.axd?ResourceStreamID=Blank.gif

For anyone else with the same issue, until Microsoft gives us a proper fix, I have a potential workaround. It's messy, though, because it looks like the HTML string is composed by the rendering engine, then sent to the HtmlTextWriter in one big chunk.

In your .aspx.cs:

protected override void Render( HtmlTextWriter writer )
{
    if( Page.IsPostBack )
    {
        writer = new HtmlTextWriter_Fix( writer.InnerWriter );
    }

    base.Render( writer );
}

class HtmlTextWriter_Fix : HtmlTextWriter
{
    public HtmlTextWriter_Fix( TextWriter writer ) : base( writer )
    {
    }

    public override void Write( string s )
    {
        if( s.Contains( "ResourceStreamID=Blank.gif ALT=\"Blank image" ) )
            s = s.Replace( "ResourceStreamID=Blank.gif ALT=\"Blank image", "ResourceStreamID=Blank.gif\" alt=\"No content" );//[awaiss] The length has to match or the resulting content won't be parsed correctly (not sure why)

        base.Write( s );
    }
}

Yes, it is still an issue. The problem is in the NuGet package. If this isn't the place to report problems in code, could you please point me to the proper place for a bug report?

I believe this bug has been around for 20 years now. It was not a problem with IE but is currently a problem with Edge, Chrome, Firefox, and Safari. Even further, I understand it even came along with the codebase with the newer Power BI Server for the classic-style paginated reports. These are reports created with the Power BI Report Builder. I believe these reports also use an RDL-derived language.

It's a bug with the Line control. The Line control will display broken images before and after the line unless an InterationID is tacked onto the end of the URL, like this:
&IterationId=0

A report dev could switch out the used Line for a different control and add a border to one side to simulate a line.

Check out the article AND the comments here:
https://obscureproblemsandgotchas.com/uncategorized/ssrs-report-viewer-control-broken-image/

Good luck.

Hi @Alan Waiss ,

I'm not familiar with develop.

I did some online research for your reference, hope it will be helpful to you.

https://stackoverflow.com/questions/45454067/tiny-boxes-appear-when-rendering-ssrs-reports-in-html-viewed-from-chrome

https://stackoverflow.com/questions/13498696/reportviewer-showing-broken-images-in-chrome

You may also raise the question to this forum for further help.

https://forums.asp.net/191.aspx/1?SQL+Server+Reporting+Services

Regards，

Zoe

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