Error displaying a WinForm in Design mode with a custom control on it

Question

I have a UserControl that is part of a Class library. I reference this project from my solution. This adds a control from the referenced project to my toolbox. I add tghe control to a form. Everything looks good, I compile all and run. Perfect...

But when I close the .frm with the control on it and re-open it, I get this error. The code continues to run.

It may have something to do with namespaces. The original namespace was simply "Design" and this was ambiguous and conflicting so i decided to rename it. I think that's when my problems began.

    To prevent possible data loss before loading the designer, the following errors must be resolved:   



    2 Errors   

  Ignore and Continue   
    Why am I seeing this page?   





   Could not find type 'Besi.Winforms.HtmlEditor.Editor'. Please make sure that the assembly that contains this type is referenced. If this type is a part of your development project, make sure that the project has been successfully built using settings for your current platform or Any CPU.     




Instances of this error (1)  

1.   There is no stack trace or error line information available for this error.  


Help with this error  

Could not find an associated help topic for this error. Check Windows Forms Design-Time error list   


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   The variable 'Editor1' is either undeclared or was never assigned.     Go to code  





Instances of this error (1)  

1.   BesiAdmin frmOrder.Designer.vb Line:775 Column:1   Show Call Stack  

at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.Error(IDesignerSerializationManager manager, String exceptionText, String helpLink)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeExpression(IDesignerSerializationManager manager, String name, CodeExpression expression)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeExpression(IDesignerSerializationManager manager, String name, CodeExpression expression)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeStatement(IDesignerSerializationManager manager, CodeStatement statement)  

Help with this error  

MSDN Help   


Forum posts about this error  

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Answer 1

A few things to try:

• Check your frmOrder.Designer.vb file for errors, or possibly using the wrong namespace. I know it probably says not to touch the file in a comment, but sometimes you have to. Just be careful.

• Try cleaning/rebuilding your project if you can.

• Remove and re-add the reference to your dll (and make sure you're referencing the right version with the right namespace). Maybe something is cached that shouldn't be.

• Exit and restart VS.

Answer 2

I had this issue and came across this article in addition to others.

The sum of what I did was close VS, delete .SUO files and bin/obj directories - this resolved several, but not all of the designer errors. I also looked at my Designer.cs file and, in my case, found some variable declarations that were NOT pre-fixed with namespaces (i.e. private TabControl tabs_main; instead of private System.Windows.Forms.TabControl tabs_main;), so I edited the design file to include the full namespace and re-built. That solved this issue for me.