Question

按照这里的教程

http://beyondrelational.com/modules/2/blogs/79/posts/11543/throwing-exceptions-from-wcf-service-faultexception.aspx

我最终得到了以下代码：

接口：

[ServiceContract]
public interface IAuthenticator
{
    [OperationContract]
    [FaultContract(typeof(AuthenticationException))]
    Account authenticateApplication(string userName, string Password);
}

例外：

[DataContract]
public class AuthenticationException
{
    private string validationError;

    [DataMember]
    public string ValidationError
    {
        set { validationError = value; }
        get { return validationError; }
    }

    public AuthenticationException(string valError)
    {
        validationError = valError;
    }
}

最后，这就是我在authenticateApplication的实现中抛出错误的方法：

catch (InvalidUsernameException)
{
    throw new FaultException<AuthenticationException>(new AuthenticationException("The username you entered could not be found in our database."), new FaultReason("Error"));
}

问题在于，不是将错误发送回客户端，而是应用程序WCF应用程序崩溃，说我没有处理异常。

如果重要，我的客户就是这样打电话：

try
{
    myAcc = httpProxy.authenticateApplication("some text", "some other text");
}
catch (FaultException<AuthenticationException> ex)
{
    MessageBox.Show(ex.Detail.ValidationError);
    return;
}

编辑：这是我的堆栈跟踪：

   at AuthenticatorService.Authenticator.authenticateApplication(String userName, String Password) in E:\Miscellaneous\Applications\Web 2.0 Creator\AuthenticatorService\AuthenticatorService\AuthenticatorService\Authenticator.cs:line 109
   at SyncInvokeauthenticateApplication(Object , Object[] , Object[] )
   at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs)

修改编辑：

这是完整的try catch块：

try
{
    using (myConnection)
    {
        using (myCommand)
        {
            //Tell it to execute the stored procedure on the database
            myCommand.CommandText = "findUsername";
            myCommand.CommandType = CommandType.StoredProcedure;
            myCommand.Parameters.Add("@userName", SqlDbType.NVarChar, 20);
            myCommand.Parameters["@userName"].Value = userName;

            //If the reader returns 0 rows, that means the username doesn't exist in the database, so step there and return an exception
            using (myReader)
            {
                myReader = myCommand.ExecuteReader();
                if (myReader.HasRows == false)
                {
                    InvalidUsernameException iue = new InvalidUsernameException();
                    throw iue;
                }
                else //Else we store the fields
                {
                    myAcc.Password = myReader[1].ToString();
                    isActive = Convert.ToBoolean(myReader[2]);
                    myAcc.Key = myReader[3].ToString();
                    myAcc.ExpiryDate = myReader[4].ToString();
                }
            }
        }
    }
}
catch (SqlException)
{
    throw new FaultException<AuthenticationException>(new AuthenticationException("There was an error while connecting the database, please contact support."), new FaultReason("Error"));
}
catch (InvalidOperationException)
{
    throw new FaultException<AuthenticationException>(new AuthenticationException("An error in the program while connecting to the database."), new FaultReason("Error"));
}
catch (InvalidUsernameException)
{
    throw new FaultException<AuthenticationException>(new AuthenticationException("The username you entered could not be found in our database."), new FaultReason("Error"));
}
catch (Exception)
{
    throw new FaultException<AuthenticationException>(new AuthenticationException("There was a general error during the process."), new FaultReason("Error"));
}

Answer 1

尝试向AuthenticationException类添加无参数构造函数。或者：

[DataContract]
public class AuthenticationException
{
    [DataMember]
    public string ValidationError { get; set; }
}

并在您的服务中：

throw new FaultException<AuthenticationException>(
    new AuthenticationException 
    { 
        ValidationError = "The username you entered could not be found in our database."
    }, 
    new FaultReason("Error")
);

还要记住，这仅适用于try / catch块内发生的异常。如果在服务的某些其他部分中发生了一些未转换为FaultContract的其他异常，则不会在客户端上将其作为FaultException<T>捕获。

此外，建议使用custom IErrorHandler将WCF服务的异常处理集中在一个位置，该{{3}}将传播错误，而不是在代码周围放置try / catch块。

Answer 2

在访问其字段之前，您似乎需要调用myReader.Read。

Answer 3

我在此页面找到了问题的答案：

http://sergecalderara.wordpress.com/2008/11/25/systemservicemodelfaultexception1-was-unhandled-by-user-code/

您需要禁用这些visual studio选项：

enter image description here

无法从我的WCF应用程序发送异常

3 个答案: