我正在为教区创建一个web应用程序。 这是一个我使用SQL Server的CRUD Web应用程序。 我在product-list.component页面上创建了OnDelete方法，以便能够删除单个产品。 该方法是正确的，但是我有一个问题，就是该表中存在与禁止删除的“ CommandRighe”表相关的关系。 我使用try catch修改了OnDelete方法，以便能够拦截错误代码并将错误消息发送给用户。 它不起作用，我想知道如何处理该问题，以便向用户发送一条错误消息，告诉他该记录无法删除。 我能怎么做 ？ 谢谢
Moreno
System.Data.Entity.Infrastructure.DbUpdateException non è stata gestita dal codice utente
HResult=-2146233087
Message=Errore durante l'aggiornamento delle voci. Per ulteriori dettagli, vedere l'eccezione interna.
Source=EntityFramework
StackTrace:
in System.Data.Entity.Internal.InternalContext.SaveChanges()
in System.Data.Entity.Internal.LazyInternalContext.SaveChanges()
in System.Data.Entity.DbContext.SaveChanges()
in WebApiSif.Controllers.PRODOTTIController.DeletePRODOTTI(Int32 id) in I:\Angular Project\SifWork\WebApiSif\WebApiSif\Controllers\PRODOTTIController.cs:riga 162
in lambda_method(Closure , Object , Object[] )
in System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass6_2.<GetExecutor>b__2(Object instance, Object[] methodParameters)
in System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
in System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)
InnerException:
HResult=-2146233087
Message=Errore durante l'aggiornamento delle voci. Per ulteriori dettagli, vedere l'eccezione interna.
Source=EntityFramework
StackTrace:
in System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update()
in System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.<Update>b__2(UpdateTranslator ut)
in System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update[T](T noChangesResult, Func`2 updateFunction)
in System.Data.Entity.Core.EntityClient.Internal.EntityAdapter.Update()
in System.Data.Entity.Core.Objects.ObjectContext.<SaveChangesToStore>b__35()
in System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
in System.Data.Entity.Core.Objects.ObjectContext.SaveChangesToStore(SaveOptions options, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction)
in System.Data.Entity.Core.Objects.ObjectContext.<>c__DisplayClass2a.<SaveChangesInternal>b__27()
in System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)
in System.Data.Entity.Core.Objects.ObjectContext.SaveChangesInternal(SaveOptions options, Boolean executeInExistingTransaction)
in System.Data.Entity.Core.Objects.ObjectContext.SaveChanges(SaveOptions options)
in System.Data.Entity.Internal.InternalContext.SaveChanges()
InnerException:
Class=16
ErrorCode=-2146232060
HResult=-2146232060
LineNumber=1
Message=L'istruzione DELETE è in conflitto con il vincolo REFERENCE "FK_CommandaRighe_PRODOTTI". Il conflitto si è verificato nella tabella "dbo.CommandaRighe", column 'NProdotto' del database "SifDB".
L'istruzione è stata interrotta.
Number=547
Procedure=""
Server=DESKTOP-P3TEF6K\SQLEXPRESS
Source=.Net SqlClient Data Provider
State=0
StackTrace:
in System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
in System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
in System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
in System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
in System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString, Boolean isInternal, Boolean forDescribeParameterEncryption, Boolean shouldCacheForAlwaysEncrypted)
in System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, Boolean inRetry, SqlDataReader ds, Boolean describeParameterEncryptionRequest)
in System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry)
in System.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, String methodName, Boolean sendToPipe, Int32 timeout, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry)
in System.Data.SqlClient.SqlCommand.ExecuteNonQuery()
in System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.<NonQuery>b__0(DbCommand t, DbCommandInterceptionContext`1 c)
in System.Data.Entity.Infrastructure.Interception.InternalDispatcher`1.Dispatch[TTarget,TInterceptionContext,TResult](TTarget target, Func`3 operation, TInterceptionContext interceptionContext, Action`3 executing, Action`3 executed)
in System.Data.Entity.Infrastructure.Interception.DbCommandDispatcher.NonQuery(DbCommand command, DbCommandInterceptionContext interceptionContext)
in System.Data.Entity.Internal.InterceptableDbCommand.ExecuteNonQuery()
in System.Data.Entity.Core.Mapping.Update.Internal.DynamicUpdateCommand.Execute(Dictionary`2 identifierValues, List`1 generatedValues)
in System.Data.Entity.Core.Mapping.Update.Internal.UpdateTranslator.Update()
InnerException:
Message = The DELETE statement conflicts with the REFERENCE constraint "FK_CommandaRighe_PRODOTTI". The conflict occurred in the "dbo.CommandaRighe" table, column 'NProduct' of the "SifDB" database.
The instruction has been interrupted.
onDelete（id：number）{
if (confirm('Confermi la cancellazione del Record ?')) {
try {
this.service.deleteProdotti(id).then(res => { // this.service.deleteProdotti(id).subscribe(res => {
this.service.refreshList();
this.toastr.warning('Cancellazione eseguita con successo', Header_Msg);
});
} catch (error) {
console.error('errore in cancellazione: ' + error);
}
}
}
-----------------------------------------
the overall class is as follows
import {Component, OnInit, SystemJsNgModuleLoader} from '@ angular / core';
import {Products} from 'src / app / model / prodotti.model';
import {ProductsListService} from 'src / app / features / products / components / products-list / products-list.service';
import {ToastrService} from 'ngx-toastr';
let Header_Msg = "Product Manager";
@Component ({
selector: 'app-products-list',
templateUrl: './products-list.component.html',
styleUrls: ['./products-list.component.css']
})
export class ProductsListComponent implements OnInit {
constructor (private service: ProductsListService, private toastr: ToastrService) {
}
ngOnInit () {
this.service.refreshList ();
}
populateForm (emp: Products) {
this.service.formData = Object.assign ({}, emp);
}
onDelete (id: number) {
if (confirm ('Confirm the deletion of the record?')) {
try {
this.service.deleteProducts (id) .then (res => {// this.service.deleteProdotti (id) .subscribe (res => {
this.service.refreshList ();
this.toastr.warning ('Successful deletion', Header_Msg);
});
} catch (error) {
console.error ('error in deletion:' + error);
}
}
}
}`enter code here`