Could not load file or assembly 'Microsoft.ReportViewer.WebForms'

I've installed Microsoft.ReportViewer.2012.Runtime nuget package and problem has been solved without installing ReportViewer.msi or sql feature pack 12

You need to reference both Microsoft.ReportViewer.WebForms and Microsoft.ReportViewer.Common and set the CopyLocal property to true. This will result in the dll's being copied to our bin directory (both are necessary).

I've solved the problem by copying both

• Microsoft.ReportViewer.WebForms.dll from C:\Program Files (x86)\Microsoft Visual Studio 12.0\ReportViewer
• and Microsoft.reportviewer.common.dll from C:\Program Files\Microsoft Office\Office15\ADDINS\PowerPivot Excel Add-in

into bin folder (website).

Of course web.config must have:

    <httpHandlers>
        <add path="Reserved.ReportViewerWebControl.axd" verb="*" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" validate="false" />
    </httpHandlers>

    <assemblies>

        <add assembly="Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
        <add assembly="Microsoft.ReportViewer.Common, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845DCD8080CC91" />
    </assemblies>

    <buildProviders>
        <add extension=".rdlc" type="Microsoft.Reporting.RdlBuildProvider, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
    </buildProviders>

    <system.webServer>
        <validation validateIntegratedModeConfiguration="false" />
        <handlers>
            <add name="ReportViewerWebControlHandler" preCondition="integratedMode" verb="*" path="Reserved.ReportViewerWebControl.axd" type="Microsoft.Reporting.WebForms.HttpHandler, Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91" />
        </handlers>
    </system.webServer>

And that's all. For me is ok.

Hope this helps.

I ran into the same error. My web app was pointed towards report viewer version 10.0 however if 11.0 is installed it adds a redirect in the 10.0 .dll to 11.0. This became an issue when 11.0 was uninstalled as this does not correct the redirect in the 10.0 .dll. The fix in my case was to simply uninstall and reinstall 10.0.

I had this error with an old webforms app. Turns out there was a line in the markup causing the issue. I removed it and the error disappeared.

<%@ Register assembly="Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" namespace="Microsoft.Reporting.WebForms" tagprefix="rsweb" %>

I had this error when going from version 10.0.0.0, i.e. "Microsoft.ReportViewer.WebForms, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />

to version 11.0.0.0, i.e.

"Microsoft.ReportViewer.WebForms, Version=11.0.0.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"

It took a while until I understood that not only the version was changed but also the public token key, as you can see above.

I had the same error for a different package. My problem was that a dependent project was referencing a different version. I changed them to be the same version and all was good.

My solution is:

1. Copy dll Microsoft.ReportViewer.WebForms.dll into Bin folder in your project.
2. Remove your reference.
3. Add new reference from bin folder.

I hope this can help.

Updating ReportViewer should works. Use below instruction to install updated ReportViewer from Nuget Package Manager console.

Install-Package Microsoft.ReportingServices.ReportViewerControl.WebForms

Just add below assembly reference in your aspx file.

Here, 15.0.0.0 is the version number of the ReportViewerControl.WebForms that was installed in my VS. Please check Reference of the Solution to confirm the version number. No need to add PublicTokens (if multiple installation exists, it may creates trouble again).

Upload the file Microsoft.ReportViewer.WebForms.dll to your bin directory of your web applicaion.

You can find this dll file in the bin directory of your local web application.

My trial version of DevExpress had expired. Try renewing it again.

In order to Run Report Viewer On server with Data from Server

A) Go to Project Property ----> Select Reference ------> Add Reference

1) Import (Microsoft.ReportViewer.Common.dll)-----> (Path "C:\Program Files (x86)\Microsoft Visual Studio 10.0\ReportViewer")

2) Import (Microsoft.ReportViewer.ProcessingObjectModel.dll) -----> (Path "C:\Windows\Assembly\GAC_MSIL\Microsoft.ReportViewer.ProcessingObjectModel")

3) Import (Microsoft.ReportViewer.WebForms.dll)-----> (Path "C:\Program Files (x86)\Microsoft Visual Studio 10.0\ReportViewer")

B) In Above three DLL set its "Local Copy" to True so that while Building Deployment Package it will getcopied to "Bin" folder.

C) Publish the Solution

D) After that Upload all the files along with "Bin" folder with the help of "File Zilla" software to "Web Server".

E) This will install DLL on server hence, client is not required to have "Report Viewer.dll".

This worked for me.