c# - 统一: The type LogWriter cannot be constructed

Question

对于以下“项目”，在为 DI 解析 Unity 时，我遇到了一个非常烦人且无法解释的错误。

InvalidOperationException - The type LogWriter cannot be constructed. You must configure the container to supply this value.

?ex.Message; "Resolution of the dependency failed, type = \"WindowsFormsApplication1.Performance\", name = \"(none)\".\r\nException occurred while: while resolving.\r\nException is: InvalidOperationException - The type LogWriter cannot be constructed. You must configure the container to supply this value.\r\n-----------------------------------------------\r\nAt the time of the exception, the container was:\r\n\r\n Resolving WindowsFormsApplication1.Performance,(none)\r\n Resolving parameter \"lw\" of constructor WindowsFormsApplication1.Performance(Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter lw, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionManager em)\r\n Resolving Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter,(none)\r\n"

?ex.StackTrace; " at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type t, Object existing, String name, IEnumerable1 resolverOverrides) in
e:\\Builds\\Unity\\UnityTemp\\Compile\\Unity\\Unity\\Src\\UnityContainer.cs:line
515\r\n at Microsoft.Practices.Unity.UnityContainer.DoBuildUp(Type
t, String name, IEnumerable1 resolverOverrides) in e:\Builds\Unity\UnityTemp\Compile\Unity\Unity\Src\UnityContainer.cs:line 485\r\n at Microsoft.Practices.Unity.UnityContainer.Resolve(Type t, String name, ResolverOverride[] resolverOverrides) in e:\Builds\Unity\UnityTemp\Compile\Unity\Unity\Src\UnityContainer.cs:line 173\r\n at Microsoft.Practices.Unity.UnityContainerExtensions.Resolve[T](IUnityContainer container, ResolverOverride[] overrides) in e:\Builds\Unity\UnityTemp\Compile\Unity\Unity\Src\UnityContainerExtensions.cs:line 504\r\n at WindowsFormsApplication1.Form1.OnLoad(EventArgs e) in D:\Devzone\Tasking\WindowsFormsApplication1\Form1.cs:line 33"

在表单中:

  protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            try
            {
                IUnityContainer container = new UnityContainer();
                Performance p = container.Resolve<Performance>();
            }
            catch (Exception ex)
            {

            }
        }

依赖类:

 public class Performance
    {
        public Performance(LogWriter lw, ExceptionManager em)
        {
        }
    }

配置文件:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <section name="loggingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.LoggingSettings, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" />
        <section name="exceptionHandling" type="Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.Configuration.ExceptionHandlingSettings, Microsoft.Practices.EnterpriseLibrary.ExceptionHandling, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" />
    </configSections>
    <loggingConfiguration name="" tracingEnabled="true" defaultCategory="General">
        <listeners>
            <add name="Event Log Listener" type="Microsoft.Practices.EnterpriseLibrary.Logging.TraceListeners.FormattedEventLogTraceListener, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
                listenerDataType="Microsoft.Practices.EnterpriseLibrary.Logging.Configuration.FormattedEventLogTraceListenerData, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
                source="Enterprise Library Logging" formatter="Text Formatter"
                log="" machineName="." traceOutputOptions="None" />
        </listeners>
        <formatters>
            <add type="Microsoft.Practices.EnterpriseLibrary.Logging.Formatters.TextFormatter, Microsoft.Practices.EnterpriseLibrary.Logging, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
                template="Timestamp: {timestamp}{newline}&#xA;Message: {message}{newline}&#xA;Category: {category}{newline}&#xA;Priority: {priority}{newline}&#xA;EventId: {eventid}{newline}&#xA;Severity: {severity}{newline}&#xA;Title:{title}{newline}&#xA;Machine: {localMachine}{newline}&#xA;App Domain: {localAppDomain}{newline}&#xA;ProcessId: {localProcessId}{newline}&#xA;Process Name: {localProcessName}{newline}&#xA;Thread Name: {threadName}{newline}&#xA;Win32 ThreadId:{win32ThreadId}{newline}&#xA;Extended Properties: {dictionary({key} - {value}{newline})}"
                name="Text Formatter" />
        </formatters>
        <categorySources>
            <add switchValue="All" name="General">
                <listeners>
                    <add name="Event Log Listener" />
                </listeners>
            </add>
            <add switchValue="All" name="Category2" />
        </categorySources>
        <specialSources>
            <allEvents switchValue="All" name="All Events" />
            <notProcessed switchValue="All" name="Unprocessed Category" />
            <errors switchValue="All" name="Logging Errors &amp; Warnings">
                <listeners>
                    <add name="Event Log Listener" />
                </listeners>
            </errors>
        </specialSources>
    </loggingConfiguration>
    <exceptionHandling>
        <exceptionPolicies>
            <add name="Policy">
                <exceptionTypes>
                    <add name="All Exceptions" type="System.Exception, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"
                        postHandlingAction="NotifyRethrow" />
                </exceptionTypes>
            </add>
        </exceptionPolicies>
    </exceptionHandling>
</configuration>

Answer 1

您需要将企业库扩展添加到您的容器中。没有它，容器不会读取配置文件，因此不知道如何创建 Entlib 对象，例如 LogWriter。