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Transient Error: Duplicate component name 'XXXX' RRS feed

  • Question

  • Hello, I'm working on a WinForms project in VS2017, and I keep getting this interface error, "Duplicate component name: 'XXXX'" on nearly every page I work on.

    I'm pretty certain that this is a VS error, and has nothing to do with any actual duplicated fields, as I've searched repeatedly to try and find such.

    I'd guess that it has something to do with the master pages, as the control most often complained about is the ContentPlaceHolder tag. Sometimes however, the problem interferes with other controls, like grids and datasources, making it so that they cannot be accessed through the visual panel.

    I can however continue to do most everything through the code panel, and the code compiles and runs fine but I'd like to find the source of the error in case it creeps up on me later. Then, as I keep working, editing & saving, the error will sometimes clear itself out, and everything displays normally.

    Anybody got any ideas on how to track this down in VS?

    Thanks in advance,

    Jon


    • Edited by wayvirgo Tuesday, September 3, 2019 11:11 PM
    Tuesday, September 3, 2019 8:32 PM

All replies

  • If this is a WebForm application, you can also search for “Duplicate component name” here: https://forums.asp.net/.

    What kind of control ‘XXXX’ is? Does it happen with a specific control only?

    Maybe try executing “Clean Solution” and “Rebuild Solution” from context menu of Solution in Solution Explorer panel.

    If possible, you can check it in Visual Studio 2019 too.

    Wednesday, September 4, 2019 5:19 AM
  • Hi wayvirgo,

    Welcome to the MSDN forum.

    According to your description, what error did you meet? If your errors are about codes, you can click Build+lntelliSense in the Error List Window to check the error. When you double click on the error, you can track the location of the error.

    If the errors is about building the project, you can check the detailed log to track errors in Output Window by setting the option:

     Tools-->Options-->Projects and Solutions-->Build and Run-->set Detailed in both of verbosities

    Hope it could help you.

    Best Regards,

    Perry


    MSDN Community Support Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com

    Wednesday, September 4, 2019 5:43 AM
  • Hello, I've definitely tried cleaning and rebuilding, that was my first reaction, plus I've also rebooted several times recently and installed all patches for my computer and software.

    Most often, it's the Content Placeholder in the page, that comes from the master page. Currently, I'm looking at a page, and it says "Error Creating Control - MainContent" and then "Duplicate component name 'Content2'. blah blah blah'"

    So, I go in, and rename the <asp:Content /> tag as ID='Content22', thus giving it a guaranteed unique name, save the page, and now it works for a little while, until I make any other source code change, save the page, and then BAM! Now it says 'Duplicate component name 'Content22'".

    What's up with that?

    Thursday, September 5, 2019 12:33 PM
  • Hello, I've definitely tried cleaning and rebuilding, that was my first reaction, plus I've also rebooted several times recently and installed all patches for my computer and software.

    Most often, it's the Content Placeholder in the page, that comes from the master page. Currently, I'm looking at a page, and it says "Error Creating Control - MainContent" and then "Duplicate component name 'Content2'. blah blah blah'"

    So, I go in, and rename the <asp:Content /> tag as ID='Content22', thus giving it a guaranteed unique name, save the page, and now it works for a little while, until I make any other source code change, save the page, and then BAM! Now it says 'Duplicate component name 'Content22'".

    What's up with that?

    Just noticed this... Edit source, save, page stops displaying correctly. Edit, save again, page now works correctly! Wash rinse repeat, doesn't work, wash rinse ripeat, does work!
    Thursday, September 5, 2019 12:38 PM
  • Ok, I did that, feeling hopeful the whole way, but only a very few little issues came up, and I cleared them all out, except for one, regarding Newtonsoft.Json, but I kind of doubt that would be relevant.

    The problem does still exist, and is quite repeatable for some odd reason, as I noted above, on another reply.

    --Jon

    Thursday, September 5, 2019 12:41 PM
  • Hi wayvirgo,

    Congratulations on solving most of the problems in your project. These errors are about intellisense misidentification. Just clean and rebuild your solution will help you remote the error. If the reply ishelpful for you to solve your issue, please remember to mrak it as answer.

    Besides, we recommend that you should post a new issue about the error of Newtonsoft.Json and provide more detailed inforation about this issue in a new post.

    Thanks for your understanding.

    Best Regards,

    Perry




    MSDN Community Support Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com

    Friday, September 6, 2019 7:59 AM
  • Well, the problem is definitely not resolved, and I'm concerned that whatever it is could come up to haunt me later.

    As I mentioned, I did clear up all of the little warnings that came up, but that had no effect on the behavior that I've been seeing.

    All except the Newtonsoft warning, which I don't really suspect as the cause, but at the same time, I've had no luck with fixing it, so I just might go ahead and start a new post anyways.

    --Jon

    Sunday, September 8, 2019 2:49 PM
  • Hi friend,

    Sorry for the delay. About the Newonsoft warning, is this a warning from Nuget or Build? You can go error list window to check the details about the warning if it exists. Then I suggest you can open a new thread with details in this forum if it's related to nuget packages or msbuild. Or you can share some details here, I will check it for you!

    Also, if it's related to runtime error (issue resulting from code), you may need to get support from ASP.net forum

    Have a nice day.

    Best Regards

    Lance


    MSDN Community Support
    Please remember to click "Mark as Answer" the responses that resolved your issue, and to click "Unmark as Answer" if not. This can be beneficial to other community members reading this thread. If you have any compliments or complaints to MSDN Support, feel free to contact MSDNFSF@microsoft.com.

    Friday, October 4, 2019 9:52 AM