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Trying to use system.windows.forms in C# RRS feed

  • Question

  • I've been using Powershell and want to start using C#. My plan is to start by converting some powershell code to C#. The first thing I am trying is a file dialog box. Simple I thought.

    Powershell(which works):

    $fd = New-Object system.windows.forms.openfiledialog

    I tried various things in C# but it seems to come down to :

    using System.Windows.Forms;  //"Forms" underlines red in Visual Studio 2017

    Compiler message :

    The type or namespace name 'Forms' does not exist in the namespace 'System.Windows' (are you missing an assembly reference?)

    Do I have version issues and how might I fix?

    Here is "About" for Visual Studio

    Microsoft Visual Studio Community 2017 
    Version 15.9.4
    VisualStudio.15.Release/15.9.4+28307.222
    Microsoft .NET Framework
    Version 4.8.03752

    Installed Version: Community

    Application Insights Tools for Visual Studio Package   8.14.11009.1
    Application Insights Tools for Visual Studio

    ASP.NET and Web Tools 2017   15.9.04012.0
    ASP.NET and Web Tools 2017

    ASP.NET Core Razor Language Services   15.8.31590
    Provides languages services for ASP.NET Core Razor.

    ASP.NET Web Frameworks and Tools 2017   5.2.60913.0
    For additional information, visit https://www.asp.net/

    Azure App Service Tools v3.0.0   15.9.03024.0
    Azure App Service Tools v3.0.0

    Azure Functions and Web Jobs Tools   15.9.02046.0
    Azure Functions and Web Jobs Tools

    C# Tools   2.10.0-beta2-63501-03+b9fb1610c87cccc8ceb74a770dba261a58e39c4a
    C# components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

    Common Azure Tools   1.10
    Provides common services for use by Azure Mobile Services and Microsoft Azure Tools.

    JavaScript Language Service   2.0
    JavaScript Language Service

    Microsoft Azure Tools   2.9
    Microsoft Azure Tools for Microsoft Visual Studio 2017 - v2.9.10730.2

    Microsoft Continuous Delivery Tools for Visual Studio   0.4
    Simplifying the configuration of Azure DevOps pipelines from within the Visual Studio IDE.

    Microsoft JVM Debugger   1.0
    Provides support for connecting the Visual Studio debugger to JDWP compatible Java Virtual Machines

    Microsoft Library Manager   1.0
    Install client-side libraries easily to any web project

    Microsoft MI-Based Debugger   1.0
    Provides support for connecting Visual Studio to MI compatible debuggers

    Microsoft Visual Studio Tools for Containers   1.1
    Develop, run, validate your ASP.NET Core applications in the target environment. F5 your application directly into a container with debugging, or CTRL + F5 to edit & refresh your app without having to rebuild the container.

    NuGet Package Manager   4.6.0
    NuGet Package Manager in Visual Studio. For more information about NuGet, visit http://docs.nuget.org/.

    ProjectServicesPackage Extension   1.0
    ProjectServicesPackage Visual Studio Extension Detailed Info

    ResourcePackage Extension   1.0
    ResourcePackage Visual Studio Extension Detailed Info

    ResourcePackage Extension   1.0
    ResourcePackage Visual Studio Extension Detailed Info

    SQL Server Data Tools   15.1.61810.11040
    Microsoft SQL Server Data Tools

    TypeScript Tools   15.9.20918.2001
    TypeScript Tools for Microsoft Visual Studio

    Visual Basic Tools   2.10.0-beta2-63501-03+b9fb1610c87cccc8ceb74a770dba261a58e39c4a
    Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

    Visual F# Tools 10.2 for F# 4.5   15.8.0.0.  Commit Hash: 6e26c5bacc8c4201e962f5bdde0a177f82f88691.
    Microsoft Visual F# Tools 10.2 for F# 4.5

    Visual Studio Code Debug Adapter Host Package   1.0
    Interop layer for hosting Visual Studio Code debug adapters in Visual Studio

    Visual Studio Tools for Containers   1.0
    Visual Studio Tools for Containers

    Thanks

    Tuesday, October 15, 2019 3:53 AM

Answers

  • Greetings Jethro.

    You need to have System.Windows.Forms as a reference in your project.

    Right-click on 'References' , select 'Add Reference' and look under Assemblies in the dialogue.

    If you created your project as a Windows Forms project, that reference should have been added for you automatically.

    • Marked as answer by JethroNull Wednesday, October 16, 2019 5:54 AM
    Tuesday, October 15, 2019 4:05 AM
  • The type or namespace name 'Forms' does not exist in the namespace 'System.Windows' (are you missing an assembly reference?)

    The error message is telling you that you are missing a reference to the Assembly that contains System.Windows.Forms.

    In a C# project in Visual Studio, you would use "Add Reference" to add it. In Powershell, you use

    Add-Type -AssemblyName System.Windows.Forms

    There is a nice article about using Windows Forms in Powershell here:

    https://blogs.technet.microsoft.com/stephap/2012/04/23/building-forms-with-powershell-part-1-the-form/


    Tuesday, October 15, 2019 8:23 PM
    Moderator

All replies

  • Greetings Jethro.

    You need to have System.Windows.Forms as a reference in your project.

    Right-click on 'References' , select 'Add Reference' and look under Assemblies in the dialogue.

    If you created your project as a Windows Forms project, that reference should have been added for you automatically.

    • Marked as answer by JethroNull Wednesday, October 16, 2019 5:54 AM
    Tuesday, October 15, 2019 4:05 AM
  • The type or namespace name 'Forms' does not exist in the namespace 'System.Windows' (are you missing an assembly reference?)

    The error message is telling you that you are missing a reference to the Assembly that contains System.Windows.Forms.

    In a C# project in Visual Studio, you would use "Add Reference" to add it. In Powershell, you use

    Add-Type -AssemblyName System.Windows.Forms

    There is a nice article about using Windows Forms in Powershell here:

    https://blogs.technet.microsoft.com/stephap/2012/04/23/building-forms-with-powershell-part-1-the-form/


    Tuesday, October 15, 2019 8:23 PM
    Moderator