CS0234: the type or namespace name does not exist ...

Question

0.00/5 (No votes)

See more:

I am revising a .Net FW4 project in order to add some WPF components (in net 6). In the revised .csproj,I added the 2 lines in the <propertygroup>

<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PopertyGroup>
    ...
    <TargetFramework>net6.0-windows</TargetFramework>
    <UseWPF>true</UseWPF>
    ...
  </PropertyGroup>

Then in the .cs file, I added

using System.Windows.Controls;

However, I got error, such as

CS0234: The type or namespace name does not exist in the namespace (are you missing an assembly reference?)

How to fix it? Thanks.

What I have tried:

CS0234: The type or namespace name does not exist ...

Posted 23-Apr-24 4:06am

s yu

Add a Solution

Comments

s yu 10hrs 20mins ago

I re-added a new class-library type Project into the solution, the namespace can be recognized. Before, the project type created was an ArcGIS Pro Managed Configuration, which causes the Error CS0234. Thanks to Dave and Richard for your responses.

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Dave Kreskowiak · Answer 1 · 2024-04-23T06:01:00

Solution 1

You most likely don't have a reference to PresentationFramework.dll set in your project.

Posted 23-Apr-24 6:01am

Dave Kreskowiak

Comments

s yu 23-Apr-24 13:35pm

True. When I tried to check on the PresentationFramework.dll, I got error "The project configuration 'DebugAndCPU' was not found in the project manifest. How to resolve it? Thanks.

Dave Kreskowiak 23-Apr-24 16:29pm

First, I would NEVER just edit a csproj file to change from a .NET Framework project to a .NET core project. I'd make an entirely new project and copy whatever source files I need over to the new project.

The project formats between .NET Framework and .NET (Core) are very different.

s yu 24-Apr-24 13:24pm

Actually, I also tried what you said. But I got another bug https://www.codeproject.com/Questions/5381071/IDE0005-error-using-directive-is-unnecessary?cmt=1126156#cmt1126156

Dave Kreskowiak 24-Apr-24 14:32pm

I already said what I needed to say over there, and I wouldn't have anything else to say over and above what Oringal Griff has already said.

Richard Deeming · Answer 2 · 2024-04-30T03:02:00

Solution 2

As Dave said, it's not as simple as changing the target framework and adding the UseWpf item; the project format has changed quite significantly.

Undo your changes, and use the CsprojToVs2017[^] command-line tool to update your project file to the newer format.

Posted 3 days ago

Richard Deeming