在我的WebAPI应用程序中,我试图根据我的自定义标头值在Application_BeginRequest
中登录几个单独的数据库。
为了实现这一点,我尝试修改target
中的Nlog.config
,如下所示:
<target name="database"
xsi:type="Database"
connectionString="${gdc:item=myConnectionstring}"
commandText="..sql command..">..params..</target>
并在Application_BeginRequest
我尝试将myConnectionstring
设置为:
GlobalDiagnosticsContext.Set("myConnectionString", connectionString);
但是这并没有奏效,并且出现了NLog的internalLogFile
错误:
2015-02-19 12:12:48.8776 Error Error when writing to database System.InvalidOperationException: The ConnectionString property has not been initialized.
at System.Data.SqlClient.SqlConnection.PermissionDemand()
at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)
at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
at System.Data.SqlClient.SqlConnection.Open()
at NLog.Targets.DatabaseTarget.OpenConnection(String connectionString)
at NLog.Targets.DatabaseTarget.WriteEventToDatabase(LogEventInfo logEvent)
at NLog.Targets.DatabaseTarget.Write(LogEventInfo logEvent)
我尝试使用以下参数写入db(具有常量连接字符串配置):
<parameter name="@cn" layout="${gdc:myConnectionstring}"/>
<parameter name="@cn1" layout="${gdc:item=myConnectionstring}"/>
但它们似乎是空的,但是当我调试我的WebApi Action会抛出我希望写入数据库的错误时,GlobalDiagnosticsContext.Get("myConnectionString")
会返回预期的值。
我做错了什么?为什么我可以在GlobalDiagnosticsContext.Get("myConnectionString")
中看到预期值,但${gdc:item=myConnectionstring}
会解析为空字符串?
答案 0 :(得分:3)
找到另一种方法来实现这一目标:
var databaseTarget = (DatabaseTarget)LogManager.Configuration.FindTargetByName("database");
databaseTarget.ConnectionString = connectionString;
LogManager.ReconfigExistingLoggers();
但仍然不清楚为什么GlobalDiagnosticsContext
内容不起作用..
答案 1 :(得分:2)
感谢您的解决方案!
但是,如果你想使用异步数据库目标,你需要首先获得包装目标:
DatabaseTarget databaseTarget;
var target = LogManager.Configuration.FindTargetByName("database");
if (target is AsyncTargetWrapper)
databaseTarget = (target as AsyncTargetWrapper).WrappedTarget as DatabaseTarget;
else
databaseTarget = target as DatabaseTarget;
if (databaseTarget == null)
throw new NullReferenceException("Can't find DatabaseTarget with name 'database'");
databaseTarget.ConnectionString = connectionStringSelected.ConnectionString;
LogManager.ReconfigExistingLoggers();