This error could be thrown when you try to access the Query Designer mode in an SSRS project using our ADO.NET providers. The root cause of this error is a mismatch between the versions of SSRS assemblies set in your “devenv.exe.config” file and the actual versions of your SSRS assemblies.
To resolve this, please modify the versions of the following “assemblyIdentity” entries in “devenv.exe.config” file found at C:\Program Files (x86)\Microsoft Visual Studio\2019\<your edition>\Common7\IDE\devenv.exe.config (Note that we are using Visual Studio 2019 in this example):
<dependentAssembly>
<assemblyIdentity name="Microsoft.ReportingServices.Interfaces" publicKeyToken="89845dcd8080cc91" culture="neutral" />
<bindingRedirect oldVersion="9.0.242.0-15.20.0.0" newVersion="15.20.0.0"/>
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="Microsoft.ReportingServices.Designer" publicKeyToken="89845dcd8080cc91" culture="neutral" />
<bindingRedirect oldVersion="9.0.242.0-15.20.0.0" newVersion="15.20.0.0"/>
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="Microsoft.ReportingServices.QueryDesigners" publicKeyToken="89845dcd8080cc91" culture="neutral" />
<bindingRedirect oldVersion="9.0.242.0-15.20.0.0" newVersion="15.20.0.0"/>
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity name="Microsoft.ReportingServices.QueryDesigners.Extensions" publicKeyToken="89845dcd8080cc91" culture="neutral" />
<bindingRedirect oldVersion="9.0.242.0-15.20.0.0" newVersion="15.20.0.0"/>
</dependentAssembly>
Note that you may need to add Microsoft.ReportingServices.QueryDesigners.Extensions if it is not present in your config file.
To find the right version for each assembly (DLL file) you should go to C:\Program Files (x86)\Microsoft Visual Studio\2019\<edition>\Common7\IDE\CommonExtensions\Microsoft\SSRS folder and check the AssemblyVersion. To do that use dnSpy or ILSpy tools.
In the above example, we have set “15.20.0.0” for both oldVersion and newVersion, based on what we have found in SSRS assemblies. Note that “15.20.0.0” in oldVersion comes after the (-) sign.
