Identity scaffolding in .net core 6.0 gives error message "Length cannot be less than zero."

Question

Hello,

I've been trying to scaffold various Identity pages, however I keep getting an error dialog which says "There was an error running the selected code generator: 'Length cannot be less than zero. (Parameter 'length')'". .

In the code generation log, it gives a stack trace:

Finding the generator 'identity'...  
Running the generator 'identity'...  
Length cannot be less than zero. (Parameter 'length')  
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()  
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)  
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)  
   at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)  

I'm running version 6.0.7 for the CodeGeneration package.

So is this a bug with the CodeGeneration package? Is there something else I should probably look into for debugging this? How can I get more information for the cause of this error dialog?

Answer 1

same problem here

Building project ...  
Finding the generator 'identity'...  
Running the generator 'identity'...  
Length cannot be less than zero. (Parameter 'length')  
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()  
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)  
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)  
   at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)  
RunTime 00:00:05.12  

dotnet list package
Project 'WebAuthentication' has the following package references
[net6.0]:
Top-level Package Requested Resolved

Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore 6.0.9 6.0.9
Microsoft.AspNetCore.Identity.EntityFrameworkCore 6.0.9 6.0.9
Microsoft.AspNetCore.Identity.UI 6.0.9 6.0.9
Microsoft.EntityFrameworkCore.Design 6.0.9 6.0.9
Microsoft.EntityFrameworkCore.SqlServer 6.0.9 6.0.9
Microsoft.EntityFrameworkCore.Tools 6.0.9 6.0.9
Microsoft.VisualStudio.Web.CodeGeneration.Design 6.0.10 6.0.10
Serilog.AspNetCore 6.0.1 6.0.1
Serilog.Settings.Configuration 3.4.0 3.4.0
Serilog.Sinks.Console 4.1.0 4.1.0
Serilog.Sinks.Debug 2.0.0 2.0.0
Serilog.Sinks.File 5.0.0 5.0.0

I already tried to scaffold with "-f" and "$env:codegen_trace=1", but I still get the same error without a hint. Plz help!

Answer 2

Still have the same problem even with latest nuget packages and on .NET 7. Is there any way to get a more detailed error message?

Project 'Portal' has the following package references
   [net7.0]: 
   Top-level Package                                           Requested   Resolved
   > DevExpress.Blazor                                         22.2.5      22.2.5  
   > DevExpress.Blazor.Server.WebAssembly                      22.2.5      22.2.5
   > Microsoft.AspNetCore.Diagnostics                          2.2.0       2.2.0   
   > Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore      7.0.4       7.0.4   
   > Microsoft.AspNetCore.Identity.EntityFrameworkCore         7.0.4       7.0.4   
   > Microsoft.AspNetCore.Identity.UI                          7.0.4       7.0.4   
   > Microsoft.EntityFrameworkCore                             7.0.4       7.0.4   
   > Microsoft.EntityFrameworkCore.Sqlite                      7.0.4       7.0.4   
   > Microsoft.EntityFrameworkCore.SqlServer                   7.0.4       7.0.4   
   > Microsoft.EntityFrameworkCore.Tools                       7.0.4       7.0.4   
   > Microsoft.VisualStudio.Web.CodeGeneration.Design          7.0.5       7.0.5   


Finding the generator 'identity'...
Running the generator 'identity'...
No database provider found. Using 'SqlServer' by default for new DbContext creation!  (Even though I have selected this in menu, it says that there is no provider found)
Length cannot be less than zero. (Parameter 'length')
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)

Answer 3

I have the same problem with .NET 7, blazor server app with Individual Accounts.

I can however create a new blazor server with individual accounts and scaffold without problems...
I can copy the scaffolded files (login and register) into the original project and I can do changes to the HTML but I can no longer login or register if I do this.

Next time I create a Blazor server or MVC, I'm going to scaffold immediately to avoid this crap...