VisualStudio: 是否有“移动类到不同的名称空间”的重构？

As mentioned in the comments, this answer is now outdated. Please see the up-to-date answer below

Resharper is the only tool I am aware of what has this ability. There is also a lot of other functionality that it has that is missing in CodeRush and Refactor!

Visual Studio 2010 has the possibility to rename a namespace. Place the cursor over the namespace name and press F2. Or simply rename it in the code and press Shift+Alt+F10, Enter after seeing the red squiggle appear.

Reharper can also rename namespaces. Quote:

The Rename Namespace refactoring allows users to rename a specific namespace and automatically correct all references to the namespace in the code. The following usages are renamed:

• Namespace statements
• Using directives
• Qualified names of types

Since the answer above was provided (I'm guessing) this feature has been added to CodeRush. Just place the carat on the Type to be moved and you'll see a Move Type to Namespace option on the Refactor! context menu. This will move the type to the new namespace and update references. You may still want to move the file to a solution folder that matches the name of the namespace though.

With Resharper: CTRL+R+O

Then press the down arrow key twice to select Move Type To Another Namespace.

This answer applies to at least Visual Studio 2013 and 2015 with no resharper required

1. Move class files to new folder
2. Open 'Find and replace'
3. Select 'Replace in Files'
4. Type the original namespace definition in the 'Find what' field eg. MyCorp.AppStuff.Api
5. Type the new namespace definition in the 'Replace with' field eg. MyCorp.AppStuff.Api.Extensions
6. Select the new folder using the 'Look in' field's browse button ..., or type the folder path
7. Press the Replace All button

If you cannot, or do not want to use Re$harper, Notepad++ is your friend:

1. Make sure you don't have usaved changes inside Visual Studio for the files you need to move to the new namespace
2. Open all the files that contain the namespace that needs to be changed in Notepad++
3. Open Find & Replace (CTRL + H)
4. Fill the Find what and Replace with fields
5. Press Replace All in All Opened Documents
6. Save all changes in all documents (CTRL + SHIFT + S)
7. Switch to Visual Studio and reload all the documents (Yes to all at the prompt)

DONE

There are partial solutions for VS 2015 & VS 2017 without Resharper using free extensions.

One extension which I like today (end of 2017) is the Fix Namespace VS Extension: https://marketplace.visualstudio.com/items?itemName=vs-publisher-599079.FixNamespace#overview

It analyses the folder structure of your solution and offers namespace refactoring using that. Unfortunately it isn't perfect: It doesn't track dependencies that well, but solved the lion's share of the work for me.

Visual Studio 2019 provides at least 2 built-in options:

'Move to namespace...' refactoring can be triggered on any class, and VS will prompt for the target namespace.

'Change namespace to...' refactoring is provided for when the current file namespace doesn't match with the folder structure.

This can be used to move individual classes to a different namespace by:

1. creating the desired folder structure
2. moving the file
3. applying the mentioned refactoring (CTRL+. with the cursor over the namespace)

These operation ensures that all references are updated accordingly.

It's not the best outcome but can be done without plugins or tools, only with Visual Studio. Find and replace in Entire Solution, Match case, Match whole word. Find what: class name, Replace with: New.Namespace.ClassName (fully qualified class name).

If you have 100+ references of the moved class and other classes in old namespace what are not moved this is the only foolproof and free solution I found. The only case when it leads to errors is when you have same class name in other namespace.