Trace.WriteLineIf 方法

参考

定义

命名空间:: System.Diagnostics

程序集:: System.Diagnostics.TraceSource.dll

程序集:: System.dll

程序集:: netstandard.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

如果条件 true，则向 Listeners 集合中的跟踪侦听器写入有关跟踪的信息。

重载

WriteLineIf(Boolean, Object, String)	如果条件 `true`，则向 Listeners 集合中的跟踪侦听器写入类别名称和对象的 ToString() 方法的值。
WriteLineIf(Boolean, Object)	如果条件 `true`，将对象的 ToString() 方法的值写入 Listeners 集合中的跟踪侦听器。
WriteLineIf(Boolean, String)	如果条件 `true`，则向 Listeners 集合中的跟踪侦听器写入消息。
WriteLineIf(Boolean, String, String)	如果条件 `true`，则向 Listeners 集合中的跟踪侦听器写入类别名称和消息。

WriteLineIf(Boolean, Object, String)

Source:: Trace.cs

Source:: Trace.cs

Source:: Trace.cs

如果条件 true，则向 Listeners 集合中的跟踪侦听器写入类别名称和对象的 ToString() 方法的值。

public:
 static void WriteLineIf(bool condition, System::Object ^ value, System::String ^ category);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, object? value, string? category);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, object value, string category);

[<System.Diagnostics.Conditional("TRACE")>]
static member WriteLineIf : bool * obj * string -> unit

Public Shared Sub WriteLineIf (condition As Boolean, value As Object, category As String)

参数

condition: Boolean

true 导致写入消息;否则，false。

value: Object

一个 Object，其名称将发送到 Listeners。

category: String

用于组织输出的类别名称。

属性: ConditionalAttribute

示例

以下示例创建一个名为 generalSwitch的 TraceSwitch。此开关在代码示例外部设置。

如果开关设置为 TraceLevelError 或更高版本，则本示例将第一条错误消息输出到 Listeners。有关向 Listeners 集合添加侦听器的信息，请参阅 TraceListenerCollection 类。

然后，如果 TraceLevel 设置为 Verbose，则该示例将输出第二条错误消息，该错误消息与第一条消息位于同一行。第二条消息后跟行终止符。

// Class-level declaration.
// Create a TraceSwitch.
private:
   static TraceSwitch^ generalSwitch = 
      gcnew TraceSwitch( "General", "Entire Application" );

public:
   static void MyErrorMethod( Object^ myObject, String^ category )
   {
      #if defined(TRACE)
      // Write the message if the TraceSwitch level is set
      // to Error or higher.
      Trace::WriteIf( generalSwitch->TraceError, 
         "Invalid object for category. " );
      
      // Write a second message if the TraceSwitch level is set
      // to Verbose.
      Trace::WriteLineIf( generalSwitch->TraceVerbose, 
         myObject, category );
      #endif
   }

// Class-level declaration.
 // Create a TraceSwitch.
 static TraceSwitch generalSwitch = new TraceSwitch("General", "Entire Application");

 static public void MyErrorMethod(Object myObject, string category) {
    // Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "Invalid object for category. ");

    // Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, myObject, category);
 }

' Class-level declaration.
' Create a TraceSwitch.
Private Shared generalSwitch As New TraceSwitch("General", "Entire Application")

Public Shared Sub MyErrorMethod(myObject As Object, category As String)
    ' Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "Invalid object for category. ")
    
    ' Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, myObject, category)
End Sub

注解

默认情况下，输出将写入 DefaultTraceListener实例。

category 参数可用于对输出消息进行分组。

此方法调用跟踪侦听器的 WriteLine 方法。

继承者说明

可以使用 If...Then 语句而不是使用 WriteLineIf(Boolean, String) 语句来最大程度地减少检测应用程序的性能损失。以下两个代码示例发送相同的调试消息。但是，当跟踪关闭时，第一个示例要快得多，因为如果 mySwitch.TraceError 评估为 false 你不调用 WriteLine(String)。第二个示例始终调用 WriteLineIf(Boolean, String)，即使 mySwitch.TraceErrorfalse，也不会生成跟踪输出。这可能会导致不必要地执行任意复杂的代码。

第一个示例

if(mySwitch.TraceError)   
    Trace.WriteLine("aNumber = " + aNumber + " out of range");

第二个示例

Trace.WriteLineIf(mySwitch.TraceError, "aNumber = " + aNumber + " out of range");

另请参阅

适用于

WriteLineIf(Boolean, Object)

Source:: Trace.cs

Source:: Trace.cs

Source:: Trace.cs

如果条件 true，将对象的 ToString() 方法的值写入 Listeners 集合中的跟踪侦听器。

public:
 static void WriteLineIf(bool condition, System::Object ^ value);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, object? value);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, object value);

[<System.Diagnostics.Conditional("TRACE")>]
static member WriteLineIf : bool * obj -> unit

Public Shared Sub WriteLineIf (condition As Boolean, value As Object)

参数

condition: Boolean

true 导致写入消息;否则，false。

value: Object

一个 Object，其名称将发送到 Listeners。

属性: ConditionalAttribute

示例

以下示例创建一个名为 generalSwitch的 TraceSwitch。此开关在代码示例外部设置。

然后，如果 TraceLevel 设置为 Verbose，则示例将在与第一条消息相同的行上输出对象的名称。第二条消息后跟行终止符。

// Class-level declaration.
// Create a TraceSwitch.
private:
   static TraceSwitch^ generalSwitch = 
      gcnew TraceSwitch( "General", "Entire Application" );

public:
   static void MyErrorMethod( Object^ myObject )
   {
      #if defined(TRACE)
      // Write the message if the TraceSwitch level 
      // is set to Error or higher.
      Trace::WriteIf( generalSwitch->TraceError, "Invalid object. " );
      
      // Write a second message if the TraceSwitch level is set
      // to Verbose.
      Trace::WriteLineIf( generalSwitch->TraceVerbose, myObject );
      #endif
   }

// Class-level declaration.
 // Create a TraceSwitch.
 static TraceSwitch generalSwitch = new TraceSwitch("General", "Entire Application");

 static public void MyErrorMethod(Object myObject) {
    // Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "Invalid object. ");

    // Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, myObject);
 }

' Class-level declaration.
' Create a TraceSwitch.
Private Shared generalSwitch As New TraceSwitch("General", "Entire Application")


Public Shared Sub MyErrorMethod(myObject As Object)
    ' Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "Invalid object. ")
    
    ' Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, myObject)
End Sub

注解

默认情况下，输出将写入 DefaultTraceListener实例。

此方法调用跟踪侦听器的 WriteLine 方法。

继承者说明

第一个示例

if(mySwitch.TraceError)   
    Trace.WriteLine("aNumber = " + aNumber + " out of range");

第二个示例

Trace.WriteLineIf(mySwitch.TraceError, "aNumber = " + aNumber + " out of range");

另请参阅

适用于

WriteLineIf(Boolean, String)

Source:: Trace.cs

Source:: Trace.cs

Source:: Trace.cs

如果条件 true，则向 Listeners 集合中的跟踪侦听器写入消息。

public:
 static void WriteLineIf(bool condition, System::String ^ message);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, string? message);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, string message);

[<System.Diagnostics.Conditional("TRACE")>]
static member WriteLineIf : bool * string -> unit

Public Shared Sub WriteLineIf (condition As Boolean, message As String)

参数

condition: Boolean

true 导致写入消息;否则，false。

message: String

要写入的消息。

属性: ConditionalAttribute

示例

以下示例创建一个名为 generalSwitch的 TraceSwitch。此开关在代码示例外部设置。

然后，如果 TraceLevel 设置为 Verbose，则该示例将输出第二条错误消息，该错误消息与第一条消息位于同一行。第二条消息后跟行终止符。

// Class-level declaration.
// Create a TraceSwitch.
private:
   static TraceSwitch^ generalSwitch = 
      gcnew TraceSwitch( "General", "Entire Application" );

public:
   static void MyErrorMethod()
   {
      #if defined(TRACE)
      // Write the message if the TraceSwitch level is set to
      // Error or higher.
      Trace::WriteIf( generalSwitch->TraceError, "My error message. " );
      
      // Write a second message if the TraceSwitch level is set
      // to Verbose.
      Trace::WriteLineIf( generalSwitch->TraceVerbose, 
         "My second error message." );
      #endif
   }

// Class-level declaration.
 // Create a TraceSwitch.
 static TraceSwitch generalSwitch = new TraceSwitch("General", "Entire Application");

 static public void MyErrorMethod() {
    // Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "My error message. ");

    // Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, "My second error message.");
 }

' Class-level declaration.
' Create a TraceSwitch.
Private Shared generalSwitch As New TraceSwitch("General", "Entire Application")

Public Shared Sub MyErrorMethod()
    ' Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "My error message. ")
    
    ' Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, "My second error message.")
End Sub

注解

默认情况下，输出将写入 DefaultTraceListener实例。

此方法调用跟踪侦听器的 WriteLine 方法。

继承者说明

第一个示例

if(mySwitch.TraceError)   
    Trace.WriteLine("aNumber = " + aNumber + " out of range");

第二个示例

Trace.WriteLineIf(mySwitch.TraceError, "aNumber = " + aNumber + " out of range");

另请参阅

适用于

WriteLineIf(Boolean, String, String)

Source:: Trace.cs

Source:: Trace.cs

Source:: Trace.cs

如果条件 true，则向 Listeners 集合中的跟踪侦听器写入类别名称和消息。

public:
 static void WriteLineIf(bool condition, System::String ^ message, System::String ^ category);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, string? message, string? category);

[System.Diagnostics.Conditional("TRACE")]
public static void WriteLineIf (bool condition, string message, string category);

[<System.Diagnostics.Conditional("TRACE")>]
static member WriteLineIf : bool * string * string -> unit

Public Shared Sub WriteLineIf (condition As Boolean, message As String, category As String)

参数

condition: Boolean

true 导致写入消息;否则，false。

message: String

要写入的消息。

category: String

用于组织输出的类别名称。

属性: ConditionalAttribute

示例

以下示例创建一个名为 generalSwitch的 TraceSwitch。此开关在代码示例外部设置。

然后，如果 TraceLevel 设置为 Verbose，则该示例将输出第二条错误消息，并在第一条消息所在的同一行上输出 category。第二条消息后跟行终止符。

// Class-level declaration.
// Create a TraceSwitch.
private:
   static TraceSwitch^ generalSwitch = 
      gcnew TraceSwitch( "General", "Entire Application" );

public:
   static void MyErrorMethod( String^ category )
   {
      #if defined(TRACE)
      // Write the message if the TraceSwitch level is set 
      // to Error or higher.
      Trace::WriteIf( generalSwitch->TraceError, "My error message. " );
      
      // Write a second message if the TraceSwitch level is set
      // to Verbose.
      Trace::WriteLineIf( generalSwitch->TraceVerbose, 
         "My second error message.", category );
      #endif
   }

// Class-level declaration.
 // Create a TraceSwitch.
 static TraceSwitch generalSwitch = new TraceSwitch("General", "Entire Application");

 static public void MyErrorMethod(string category) {
    // Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "My error message. ");

    // Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, "My second error message.", category);
 }

' Class-level declaration.
' Create a TraceSwitch.
Private Shared generalSwitch As New TraceSwitch("General", "Entire Application")

Public Shared Sub MyErrorMethod(category As String)
    ' Write the message if the TraceSwitch level is set to Error or higher.
    Trace.WriteIf(generalSwitch.TraceError, "My error message. ")
    
    ' Write a second message if the TraceSwitch level is set to Verbose.
    Trace.WriteLineIf(generalSwitch.TraceVerbose, _
        "My second error message.", category)
End Sub

注解

默认情况下，输出将写入 DefaultTraceListener实例。

category 参数可用于对输出消息进行分组。

此方法调用跟踪侦听器的 WriteLine 方法。

继承者说明

第一个示例

if(mySwitch.TraceError)   
    Trace.WriteLine("aNumber = " + aNumber + " out of range");

第二个示例

Trace.WriteLineIf(mySwitch.TraceError, "aNumber = " + aNumber + " out of range");

另请参阅

适用于

通过

Trace.WriteLineIf 方法

定义

重载

WriteLineIf(Boolean, Object, String)

参数

示例

注解

继承者说明

另请参阅

适用于

WriteLineIf(Boolean, Object)

参数

示例

注解

继承者说明

另请参阅

适用于

WriteLineIf(Boolean, String)

参数

示例

注解

继承者说明

另请参阅

适用于

WriteLineIf(Boolean, String, String)

参数

示例

注解

继承者说明

另请参阅

适用于

其他资源