Troubleshooting
Cannot convert from 'long?' to 'long'
I use a code similar to the following to accept the value for a query string named Id on one of my pages of a .NET Razor Page application. It is an optional query string. Its value is then passed to another function for further processing. When I compile the code, I get the error message "cannot convert from 'long?' to 'long'"
Tags: Troubleshooting
Your target project [ProjectName] doesn't match your migrations assembly [AssemblyName]. Either change your target project or change your migrations assembly.
I am working on a project in ASP.NET Core 5.0, which contains a web application and the related class libraries. I use Entity Framework Core for data access. My DbContext is in a class library project. When I run the add-migration command I get this error.
Tags: Troubleshooting
Module not found: Can't resolve 'react-router-dom'
I got this error "Module not found: Can't resolve 'react-router-dom'" when I tried to import and use the 'react-router-dom' package in my React application. This package allows us to add routing functionality to React.
Tags: Troubleshooting
Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.
When I run my React JS application, I get the following error. Error: App(...): Nothing was returned from render. This usually means a return statement is missing. Or, to render nothing, return null.
Tags: Troubleshooting
Unable to resolve service for type 'System.Net.Http.HttpClient' while attempting to activate... error
When I tried to register a service that uses an object of System.Net.Http.HttpClient for dependency injection, I got this error "Unable to resolve service for type 'System.Net.Http.HttpClient' while attempting to activate "
Tags: Troubleshooting
The 'async' modifier can only be used in methods that have a body.
I declared a method in my interface using the async modifier and I am getting the error "The 'async' modifier can only be used in methods that have a body"
Tags: Troubleshooting
Solution For Blazor Error - Cannot provide a value for property, There is no registered service of type [TypeName]
While experimenting with Blazor, I ran into "There is no registered service of type [TypeName]" error. I was trying to use a new service on a Blazor component by injecting the service into it.
Tags: Troubleshooting
HTTP Error 502.5 - ANCM Out-Of-Process Startup Failure
I got the following error when I deployed my ASP.NET Core Razor page application to the production server after updating some NuGet packages to the latest version. HTTP Error 502.5 - ANCM Out-Of-Process Startup Failure
Tags: Troubleshooting
Unable to create an object of type '[DBContextName]'. For the different patterns supported at design time see https://go.microsoft.com/fwlink/?linkid=851728
You may get the following error when you run the add-migration command in EF Core 5. Unable to create an object of type '[DBContextName]'. For the different patterns supported at design time, see https://go.microsoft.com/fwlink/?linkid=851728
Tags: Troubleshooting
EF Core Migration Error: The query contains a projection '<>h_ Transparent Identifier 0 Collections in the final projection must be an 'IEnumerable<T>' type such as 'List<T>'.
The query contains a projection '<>h__TransparentIdentifier0 Collections in the final projection must be an 'IEnumerable' type such as 'List'. Consider using 'ToList' or some other mechanism to convert the 'IQueryable' or 'IOrderedEnumerable' into an 'IEnumerable'.
Tags: Troubleshooting