Could not load file or assembly 'System.Window

Question

I just added System.Windows.Interactivity assembly. XamlParse throw me an exception on run time:

Could not load file or assembly 'System.Windows.Interactivity, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Google search found only results related to prism - which I do not use.

Any idea why does it happen?

Answer 1

You can find this dll in Blend SDK.

Below is link to it:

http://www.microsoft.com/en-us/download/details.aspx?id=10801

Answer 2

Just a guess, might be you are not referencing the libraries in the MAIN project.

It has happened to me several times.

Answer 3

You can scan through each of your project for the version of System.Windows.Interactivity eg. 4.0.0.0 or 4.5.0.0. Also, there is a possibility that one of the third party dll that might reference, is depending on System.Windows.Interactivity. So make sure you align the version across your project. This must fix your issue.

Answer 4

Tilak's answer helped me out a big deal, but I also needed to name at least one element from assembly "i" in the XAML code. When the element is named, Visual Studio correctly hooks up the assembly.

Change

<i:InvokeCommandAction Command="{Binding MyCommand}"/>

into

<i:InvokeCommandAction Command="{Binding MyCommand}" x:Name="interactivityFix" />

This needs to be done to only one element in the entire XAML file.

Answer 5

You could check the project properties -> Build -> Output Path.

Go to the output Path director using windows explorer. Then see whether the 'System.Windows.Interactivity.dll' exist in that folder. It might because the CopyLocal flag is false or there is reason The dll file does not generate in the output path folder.

Answer 6

Sometimes, when you add a new library, in introduces a clashing version of System.Windows.Interactivity.dll.

This prevents the project from working.

To fix, add an Assembly Binding Redirect by editing your app.config to look something like this:

<?xml version="1.0"?>
<configuration>
<runtime>
  <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
    <dependentAssembly>
      <assemblyIdentity name="System.Windows.Interactivity"
                        publicKeyToken="31bf3856ad364e35"
                        culture="neutral"/>
      <bindingRedirect oldVersion="4.0.0.0"
                       newVersion="4.5.0.0" />
    </dependentAssembly>
  </assemblyBinding>
</runtime>
<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup>
<appSettings>
  <add key="TestKey" value="true"/>
</appSettings>

Don't worry about changing the PublicKeyToken, that's constant across all versions, as it depends on the name of the .dll, not the version.

Ensure that you match the newVersion in your appConfig to the actual version that you end up pointing at: