How to load assemblies in PowerShell

Question

The following PowerShell code   Get a server object which corresponds to the default instance  srv   New-Object -TypeName Microsoft SqlServer Management SMO Server     rest of the script       Gives the following error message    New-Object   Cannot find type  Microsoft SqlServer Management SMO Server   make sure  the assembly containing this type is loaded  At C  Users sortelyn       tools sql express backup backup ps1 6  char 8    srv   New-Object -TypeName Microsoft SqlServer Management SMO Server                                                                           CategoryInfo            InvalidType       New-Object   PSArgumentException   FullyQualifiedErrorId   TypeNotFound Microsoft PowerShell Commands NewObjectCommand   Every answer on the Internet writes that I have to load the assembly - well sure I can read that from the error message  -  - the question is    How do you load the assembly and make the script work

User · Answer

Here are some blog posts with numerous examples of ways to load assemblies in PowerShell v1, v2 and v3.

The ways include:

dynamically from a source file
dynamically from an assembly
using other code types, i.e. F#

v1.0 How To Load .NET Assemblies In A PowerShell Session
v2.0 Using CSharp (C#) code in PowerShell scripts 2.0
v3.0 Using .NET Framework Assemblies in Windows PowerShell

User · Answer

Make sure you have below features are installed in order    Microsoft System CLR Types for SQL Server  Microsoft SQL Server Shared Management Objects Microsoft Windows PowerShell Extensions    Also you may need to load   Add-Type -Path  C  Program Files Microsoft SQL Server 110 SDK Assemblies Microsoft SqlServer Smo dll  Add-Type -Path  C  Program Files Microsoft SQL Server 110 SDK Assemblies Microsoft SqlServer SqlWmiManagement dll

User · Answer

If you want to load an assembly without locking it during the duration of the PowerShell session  use this    bytes    System IO File   ReadAllBytes  storageAssemblyPath   System Reflection Assembly   Load  bytes    Where  storageAssemblyPath is the filepath of your assembly    This is especially usefull if you need to cleanup the ressources within your session  For example in a deployment script

User · Answer

System Reflection Assembly   LoadWithPartialName  Microsoft SqlServer Smo   worked for me

User · Answer

System Reflection Assembly   LoadWithPartialName  Microsoft SqlServer Smo

User · Answer

You can load the whole   dll assembly  with    Assembly    System Reflection Assembly   LoadFrom  C  folder file dll

User · Answer

Add the assembly references at the top    Load the required assemblies SMO and SmoExtended   System Reflection Assembly   LoadWithPartialName  Microsoft SqlServer SMO     Out-Null  System Reflection Assembly   LoadWithPartialName  Microsoft SqlServer SmoExtended     Out-Null

User · Answer

Most people know by now that System Reflection Assembly LoadWithPartialName is deprecated  but it turns out that Add-Type -AssemblyName Microsoft VisualBasic does not behave much better than LoadWithPartialName   Rather than make any attempt to parse your request in the context of your system   Add-Type  looks at a static  internal table to translate the  quot partial name quot  to a  quot full name quot   If your  quot partial name quot  doesn t appear in their table  your script will fail  If you have multiple versions of the assembly installed on your computer  there is no intelligent algorithm to choose between them  You are going to get whichever one appears in their table  probably the older  outdated one  If the versions you have installed are all newer than the obsolete one in the table  your script will fail  Add-Type has no intelligent parser of  quot partial names quot  like  LoadWithPartialNames   What Microsoft s  Net teams says you re actually supposed to do is something like this  Add-Type -AssemblyName  Microsoft VisualBasic  Version 10 0 0 0  Culture neutral  PublicKeyToken b03f5f7f11d50a3a   Or  if you know the path  something like this  Add-Type -Path  C  WINDOWS Microsoft Net assembly GAC MSIL Microsoft VisualBasic v4 0 10 0 0 0  b03f5f7f11d50a3a Microsoft VisualBasic dll   That long name given for the assembly is known as the strong name  which is both unique to the version and the assembly  and is also sometimes known as the full name  But this leaves a couple questions unanswered   How do I determine the strong name of what s actually being loaded on my system with a given partial name   System Reflection Assembly   LoadWithPartialName  TypeName  Location   System Reflection Assembly   LoadWithPartialName  TypeName  FullName    These should also work  Add-Type -AssemblyName  TypeName -PassThru   Select-Object -ExpandProperty Assembly   Select-Object -ExpandProperty FullName -Unique   If I want my script to always use a specific version of a  dll but I can t be certain of where it s installed  how do I determine what the strong name is from the  dll   System Reflection AssemblyName   GetAssemblyName  Path  FullName    Or  Add-Type  Path -PassThru   Select-Object -ExpandProperty Assembly   Select-Object -ExpandProperty FullName -Unique   If I know the strong name  how do I determine the  dll path   Reflection Assembly   Load  Microsoft VisualBasic  Version 10 0 0 0  Culture neutral  PublicKeyToken b03f5f7f11d50a3a   Location   And  on a similar vein  if I know the type name of what I m using  how do I know what assembly it s coming from   Reflection Assembly   GetAssembly  Type   Location  Reflection Assembly   GetAssembly  Type   FullName  How do I see what assemblies are available    I suggest the GAC PowerShell module   Get-GacAssembly -Name  Microsoft SqlServer Smo     Select Name  Version  FullName works pretty well   How can I see the list that Add-Type uses   This is a bit more complex  I can describe how to access it for any version of PowerShell with a  Net reflector  see the update below for PowerShell Core 6 0   First  figure out which library Add-Type comes from  Get-Command -Name Add-Type   Select-Object -Property DLL  Open the resulting DLL with your reflector   I ve used ILSpy for this because it s FLOSS  but any C  reflector should work   Open that library  and look in Microsoft Powershell Commands Utility   Under Microsoft Powershell Commands  there should be AddTypeCommand  In the code listing for that  there is a private class  InitializeStrongNameDictionary     That lists the dictionary that maps the short names to the strong names   There s almost 750 entries in the library I ve looked at  Update  Now that PowerShell Core 6 0 is open source   For that version  you can skip the above steps and see the code directly online in their GitHub repository  I can t guarantee that that code matches any other version of PowerShell  however  Update 2  Powershell 7  does not appear to have the hash table lookup any longer  Instead they use a LoadAssemblyHelper   method which the comments call  quot the closest approximation possible quot  to LoadWithPartialName  Basically  they do this  loadedAssembly   Assembly Load new AssemblyName assemblyName     Now  the comments also say  quot users can just say Add-Type -AssemblyName Forms  instead of System Windows Forms  quot   However  that s not what I see in Powershell v7 0 3 on Windows 10 2004    Returns an error Add-Type -AssemblyName Forms    Returns an error  System Reflection Assembly   Load  System Reflection AssemblyName   new  Forms       Works fine Add-Type -AssemblyName System Windows Forms    Works fine  System Reflection Assembly   Load  System Reflection AssemblyName   new  System Windows Forms     So the comments appear to be a bit of a mystery  I don t know exactly what the logic is in Assembly Load AssemblyName  when there is no version or public key token specified  I would expect that this has many of the same problems that LoadWithPartialName does like potentially loading the wrong version of the assembly if you have multiple installed

User · Answer

LoadWithPartialName has been deprecated   The recommended solution for PowerShell V3 is to use the Add-Type cmdlet e g    Add-Type -Path  C  Program Files Microsoft SQL Server 110 SDK Assemblies Microsoft SqlServer Smo dll    There are multiple different versions and you may want to pick a particular version    -

User · Answer

None of the answers helped me  so I m posting the solution that worked for me  all I had to do is to import the SQLPS module  I realized this when by accident I ran the Restore-SqlDatabase command and started working  meaning that the assembly was referenced in that module somehow   Just run   Import-module SQLPS   Note  Thanks Jason for noting that SQLPS is deprecated  instead run   Import-Module SqlServer   or  Install-Module SqlServer

User · Answer

You could use LoadWithPartialName  However  that is deprecated as they said   You can indeed go along with Add-Type  and in addition to the other answers  if you don t want to specify the full path of the  dll file  you could just simply do   Add-Type -AssemblyName  Microsoft SqlServer Management SMO    To me this returned an error  because I do not have SQL Server installed  I guess   however  with this same idea I was able to load the Windows Forms assembly   Add-Type -AssemblyName  System Windows Forms    You can find out the precise assembly name belonging to the particular class on the MSDN site

[powershell] How to load assemblies in PowerShell?

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