对于以下“项目”，我在解析Unity for DI时会遇到一个非常烦人且无法解释的错误。
InvalidOperationException - 无法构造LogWriter类型。 您必须配置容器以提供此值。
？ex.Message; “依赖项的解析失败，类型= \“WindowsFormsApplication1.Performance \”，name = \“（无）\”。\ r \ n发生以下情况时发生异常：解析时。\ r \ n \ nException 是：InvalidOperationException - LogWriter类型不能 建造。您必须配置容器以提供此功能 值。\ r \ n -------------------------------------------- --- \ r \ nAtt 异常时间，容器是：\ r \ n \ r \ n解析 WindowsFormsApplication1.Performance，（none）\ r \ n解析参数 “lw”的构造函数 WindowsFormsApplication1.Performance（Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter LW， Microsoft.Practices.EnterpriseLibrary.ExceptionHandling.ExceptionManager em）\ r \ n解析 Microsoft.Practices.EnterpriseLibrary.Logging.LogWriter，（无）\ r \ n“个
？ex.StackTrace; “ 在 Microsoft.Practices.Unity.UnityContainer.DoBuildUp（Type t，Object 现有的，String名称，IEnumerable
1 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：\构建\统一\ UnityTemp \编译\统一\统一\ SRC \ UnityContainer.cs：线 485 \ r \ n在Microsoft.Practices.Unity.UnityContainer.Resolve（类型t， 字符串名称，ResolverOverride [] resolverOverrides）in E：\构建\统一\ UnityTemp \编译\统一\统一\ SRC \ UnityContainer.cs：线 173 \ r \ n at Microsoft.Practices.Unity.UnityContainerExtensions.Resolve [T]（IUnityContainer 容器，ResolverOverride []覆盖）in E：\构建\统一\ UnityTemp \编译\统一\统一\ SRC \ UnityContainerExtensions.cs：线 504 \ r \ n在WindowsFormsApplication1.Form1.OnLoad（EventArgs e）中 D：\ Devzone \ Tasking \ WindowsFormsApplication1 \ Form1.cs：第33行“
表格形式：
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}
Message: {message}{newline}
Category: {category}{newline}
Priority: {priority}{newline}
EventId: {eventid}{newline}
Severity: {severity}{newline}
Title:{title}{newline}
Machine: {localMachine}{newline}
App Domain: {localAppDomain}{newline}
ProcessId: {localProcessId}{newline}
Process Name: {localProcessName}{newline}
Thread Name: {threadName}{newline}
Win32 ThreadId:{win32ThreadId}{newline}
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 & 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>
答案 0 :(得分：11)
您需要将Enterprise Library扩展添加到容器中。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，如LogWriter。
答案 1 :(得分：1)
Activation error occured while trying to get instance of type LogWriter, key ""
检查你的配置文件，它必须有正确的默认'loggingConfiguration'部分
答案 2 :(得分：0)
为了让Unity构建你的Performance类，它需要知道如何构造ILogWriter的实现。
我无法在代码中看到你告诉Unity要为ILogWriter接口创建什么类，所以我怀疑你可能需要添加它。
答案 3 :(得分：0)
LogWriter没有空构造函数或具有所有具体类型参数的构造函数：LogWriter Constructor。
因此Unity无法构建它，正如它所说，它需要您的帮助，通过配置容器来提供实现。
作为确认，ExceptionManager可能会被解决，因为它只有一个constructor，无参数：）
答案 4 :(得分：0)
试试这个：
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
try
{
IUnityContainer container = new UnityContainer();
container.RegisterType<ILogWriter, LogWriter>();
container.RegisterType<ExceptionManager>();
container.RegisterType<Performance>(new InjectionConstructor(typeof(ILogWriter), typeof(ExceptionManager));
Performance p = container.Resolve<Performance>();
}
catch (Exception ex)
{
}
}