Good Day
I have an issue where I am trying to retrieve the details from a single row in an SQL View and to display the details on a dashboard. I have tried 2 ways of doing this and I get the same error each way. This first was a custom method and the second through the "Invoke data source methods" in the IDE.
As both give the same error I will only mention the one way which is the "Invoke data source methods" in the IDE.
I Invoke the data source method and set the initial property with the result.
I then set a second property with result.FirstOrDefault()
I put a label on the page and set its text property to on of the fields.
When this is run, on the initial load everything works as expected however if you refresh the page it will return a blank page with the following error on the console log:
dotnet: fail: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost[111]
Unhandled exception in circuit 'nqXAa5qgli9w3VxY36w1EZc3olbaiJVCkIBxvxAvo8o'.
System.NullReferenceException: Object reference not set to an instance of an object.
at MasterDashboard.Pages.SalesAccountsDetails.b__0_3(RenderTreeBuilder __builder3)
at Microsoft.AspNetCore.Components.CascadingValue`1.Render(RenderTreeBuilder builder)
at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder batchBuilder, RenderFragment renderFragment, Exception& renderFragmentException)
dotnet: warn: Microsoft.AspNetCore.Components.Server.Circuits.RemoteRenderer[100]
Unhandled exception rendering component: Cannot access a disposed context instance. A common cause of this error is disposing a context instance that was resolved from dependency injection and then later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose' on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the dependency injection container take care of disposing context instances.
Object name: 'MasterdbContext'.
System.ObjectDisposedException: Cannot access a disposed context instance. A common cause of this error is disposing a context instance that was resolved from dependency injection and then later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose' on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the dependency injection container take care of disposing context instances.
Object name: 'MasterdbContext'.
at Microsoft.EntityFrameworkCore.DbContext.CheckDisposed()
at Microsoft.EntityFrameworkCore.DbContext.get_ContextServices()
at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
at Microsoft.EntityFrameworkCore.DbContext.get_ChangeTracker()
at Microsoft.EntityFrameworkCore.Query.CompiledQueryCacheKeyGenerator.GenerateCacheKeyCore(Expression query, Boolean async)
at Microsoft.EntityFrameworkCore.Query.RelationalCompiledQueryCacheKeyGenerator.GenerateCacheKeyCore(Expression query, Boolean async)
at Microsoft.EntityFrameworkCore.SqlServer.Query.Internal.SqlServerCompiledQueryCacheKeyGenerator.GenerateCacheKey(Expression query, Boolean async)
at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
at MasterDashboard.Pages.SalesAccountsDetailsComponent.Load() in C:\git\masterdashboard-web\server\Pages\SalesAccountsDetails.razor.designer.cs:line 117
at MasterDashboard.Pages.SalesAccountsDetailsComponent.OnInitializedAsync() in C:\git\masterdashboard-web\server\Pages\SalesAccountsDetails.razor.designer.cs:line 109
at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
dotnet: fail: Microsoft.AspNetCore.Components.Server.Circuits.CircuitHost[111]
Unhandled exception in circuit 'nqXAa5qgli9w3VxY36w1EZc3olbaiJVCkIBxvxAvo8o'.
System.ObjectDisposedException: Cannot access a disposed context instance. A common cause of this error is disposing a context instance that was resolved from dependency injection and then later trying to use the same context instance elsewhere in your application. This may occur if you are calling 'Dispose' on the context instance, or wrapping it in a using statement. If you are using dependency injection, you should let the dependency injection container take care of disposing context instances.
Object name: 'MasterdbContext'.
at Microsoft.EntityFrameworkCore.DbContext.CheckDisposed()
at Microsoft.EntityFrameworkCore.DbContext.get_ContextServices()
at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
at Microsoft.EntityFrameworkCore.DbContext.get_ChangeTracker()
at Microsoft.EntityFrameworkCore.Query.CompiledQueryCacheKeyGenerator.GenerateCacheKeyCore(Expression query, Boolean async)
at Microsoft.EntityFrameworkCore.Query.RelationalCompiledQueryCacheKeyGenerator.GenerateCacheKeyCore(Expression query, Boolean async)
at Microsoft.EntityFrameworkCore.SqlServer.Query.Internal.SqlServerCompiledQueryCacheKeyGenerator.GenerateCacheKey(Expression query, Boolean async)
at Microsoft.EntityFrameworkCore.Query.Internal.QueryCompiler.Execute[TResult](Expression query)
at Microsoft.EntityFrameworkCore.Query.Internal.EntityQueryProvider.Execute[TResult](Expression expression)
at System.Linq.Queryable.FirstOrDefault[TSource](IQueryable`1 source)
at MasterDashboard.Pages.SalesAccountsDetailsComponent.Load() in C:\git\masterdashboard-web\server\Pages\SalesAccountsDetails.razor.designer.cs:line 117
at MasterDashboard.Pages.SalesAccountsDetailsComponent.OnInitializedAsync() in C:\git\masterdashboard-web\server\Pages\SalesAccountsDetails.razor.designer.cs:line 109
at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()
at Microsoft.AspNetCore.Components.RenderTree.Renderer.GetErrorHandledTask(Task taskToHandle, ComponentState owningComponentState)
How can this be resolved?