CallerLineNumberAttribute 类

定义

public ref class CallerLineNumberAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Parameter, Inherited=false)]
public sealed class CallerLineNumberAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Parameter, Inherited=false)>]
type CallerLineNumberAttribute = class
    inherit Attribute

Public NotInheritable Class CallerLineNumberAttribute
Inherits Attribute

继承

Object

Attribute

CallerLineNumberAttribute

属性

AttributeUsageAttribute

示例

以下示例演示如何使用 CallerLineNumber 特性。 每次调用 TraceMessage 该方法时，调用方信息都将替换为可选参数的参数。

public void DoProcessing()
{
    TraceMessage("Something happened.");
}

public void TraceMessage(string message,
        [System.Runtime.CompilerServices.CallerMemberName] string memberName = "",
        [System.Runtime.CompilerServices.CallerFilePath] string sourceFilePath = "",
        [System.Runtime.CompilerServices.CallerLineNumber] int sourceLineNumber = 0)
{
    System.Diagnostics.Trace.WriteLine("message: " + message);
    System.Diagnostics.Trace.WriteLine("member name: " + memberName);
    System.Diagnostics.Trace.WriteLine("source file path: " + sourceFilePath);
    System.Diagnostics.Trace.WriteLine("source line number: " + sourceLineNumber);
}

// Sample Output:
//  message: Something happened.
//  member name: DoProcessing
//  source file path: c:\Users\username\Documents\Visual Studio 2012\Projects\CallerInfoCS\CallerInfoCS\Form1.cs
//  source line number: 31

Private Sub DoProcessing()
    TraceMessage("Something happened.")
End Sub

Public Sub TraceMessage(message As String,
        <System.Runtime.CompilerServices.CallerMemberName> Optional memberName As String = Nothing,
        <System.Runtime.CompilerServices.CallerFilePath> Optional sourcefilePath As String = Nothing,
        <System.Runtime.CompilerServices.CallerLineNumber()> Optional sourceLineNumber As Integer = 0)

    System.Diagnostics.Trace.WriteLine("message: " & message)
    System.Diagnostics.Trace.WriteLine("member name: " & memberName)
    System.Diagnostics.Trace.WriteLine("source file path: " & sourcefilePath)
    System.Diagnostics.Trace.WriteLine("source line number: " & sourceLineNumber)
End Sub

' Sample output:
'   message: Something happened.
'   member name: DoProcessing
'   source file path: C:\Users\username\Documents\Visual Studio 2012\Projects\CallerInfoVB\CallerInfoVB\Form1.vb
'   source line number: 15

注解

将 CallerLineNumber 属性应用于具有默认值的可选参数。 必须为可选参数指定显式默认值。 不能将此属性应用于未指定为可选参数的参数。

另请参阅

• CallerFilePathAttribute
• CallerMemberNameAttribute