ObsoleteAttribute.IsError 屬性

定義

命名空間:

System

組件:

netstandard.dll, System.Runtime.dll

來源:

ObsoleteAttribute.cs

會得到一個值，指示編譯器是否會將過時程式元素的使用視為錯誤。

public:
 property bool IsError { bool get(); };

public bool IsError { get; }

member this.IsError : bool

Public ReadOnly Property IsError As Boolean

屬性值

Boolean

true若過時元素使用被視為錯誤;否則，。 false 預設值為 false。

範例

以下範例定義了一個包含兩個標記為過時成員的類別。 第一個是名為 OldProperty的屬性，若被呼叫，會產生編譯器警告。 第二種方法名為 CallOldMethod，會產生編譯器錯誤。 範例中利用反射取得套用到該類型成員的 ObsoleteAttribute 屬性資訊，並顯示其 Message 屬性與 IsError 屬性的值。

using System;
using System.Reflection;

public class Example
{
   // Mark OldProperty As Obsolete.
   [ObsoleteAttribute("This property is obsolete. Use NewProperty instead.", false)]
   public string OldProperty
   { get { return "The old property value."; } }

   public string NewProperty
   { get { return "The new property value."; } }

   // Mark OldMethod As Obsolete.
   [ObsoleteAttribute("This method is obsolete. Call NewMethod instead.", true)]
   public string OldMethod()
   {
      return "You have called OldMethod.";
   }

   public string NewMethod()
   {
      return "You have called NewMethod.";
   }

   public static void Main()
   {
      // Get all public members of this type.
      MemberInfo[] members = typeof(Example).GetMembers();
      // Count total obsolete members.
      int n = 0;

      // Try to get the ObsoleteAttribute for each public member.
      Console.WriteLine("Obsolete members in the Example class:\n");
      foreach (var member in members) {
         ObsoleteAttribute[] attribs = (ObsoleteAttribute[])
                                        member.GetCustomAttributes(typeof(ObsoleteAttribute),
                                                                   false);
         if (attribs.Length > 0) {
            ObsoleteAttribute attrib = attribs[0];
            Console.WriteLine("Member Name: {0}.{1}", member.DeclaringType.FullName, member.Name);
            Console.WriteLine("   Message: {0}", attrib.Message);
            Console.WriteLine("   Warning/Error: {0}", attrib.IsError ? "Error" : "Warning");
            n++;
         }
      }

      if (n == 0)
         Console.WriteLine("The Example type has no obsolete attributes.");
   }
}
// The example displays the following output:
//       Obsolete members in the Example class:
//
//       Member Name: Example.OldMethod
//          Message: This method is obsolete. Call NewMethod instead.
//          Warning/Error: Error
//       Member Name: Example.OldProperty
//          Message: This property is obsolete. Use NewProperty instead.
//          Warning/Error: Warning

open System

type Example() =
    // Mark OldProperty As Obsolete.
    [<ObsoleteAttribute("This property is obsolete. Use NewProperty instead.", false)>]
    member _.OldProperty =
        "The old property value."

    member _.NewProperty =
        "The new property value."

    // Mark OldMethod As Obsolete.
    [<ObsoleteAttribute("This method is obsolete. Call NewMethod instead.", true)>]
    member _.OldMethod() =
        "You have called OldMethod."

    member _.NewMethod() =
        "You have called NewMethod."

// Get all public members of this type.
let members = typeof<Example>.GetMembers()
// Count total obsolete members.
let mutable n = 0

// Try to get the ObsoleteAttribute for each public member.
printfn "Obsolete members in the Example class:\n"
for m in members do
    let attribs = m.GetCustomAttributes(typeof<ObsoleteAttribute>, false) |> box :?> ObsoleteAttribute[]
    if attribs.Length > 0 then
        let attrib = attribs[0]
        printfn $"Member Name: {m.DeclaringType.FullName}.{m.Name}"
        printfn $"   Message: {attrib.Message}"
        printfn $"""   Warning/Error: {if attrib.IsError then "Error" else "Warning"}"""
        n <- n + 1

if n = 0 then
    printfn "The Example type has no obsolete attributes."
// The example displays the following output:
//       Obsolete members in the Example class:
//
//       Member Name: Example+Example.OldMethod
//          Message: This method is obsolete. Call NewMethod instead.
//          Warning/Error: Error
//       Member Name: Example+Example.OldProperty
//          Message: This property is obsolete. Use NewProperty instead.
//          Warning/Error: Warning

Imports System.Reflection

Public Module Example
   ' Mark OldProperty As Obsolete.
   <ObsoleteAttribute("This property is obsolete. Use NewProperty instead.", False)> 
   Public ReadOnly Property OldProperty As String
      Get
         Return "The old property value."
      End Get
   End Property
   
   Public ReadOnly Property NewProperty As String
      Get
         Return "The new property value."
      End Get
   End Property
   
   ' Mark OldMethod As Obsolete.
   <ObsoleteAttribute("This method is obsolete. Call NewMethod instead.", True)> 
   Public Function OldMethod() As String
      Return "You have called OldMethod."
   End Function
      
   Public Function NewMethod() As String   
      Return "You have called NewMethod."
   End Function   
   
   Public Sub Main()
      ' Get all public members of this type.
      Dim members() As MemberInfo = GetType(Example).GetMembers()
      ' Count total obsolete members.
      Dim n As Integer = 0
      
      ' Try to get the ObsoleteAttribute for each public member.
      Console.WriteLine("Obsolete members in the Example class:")
      Console.WriteLine()
      For Each member In members
         Dim attribs() As ObsoleteAttribute = CType(member.GetCustomAttributes(GetType(ObsoleteAttribute), 
                                                                             False), ObsoleteAttribute())
         If attribs.Length > 0 Then
            Dim attrib As ObsoleteAttribute = attribs(0)
            Console.WriteLine("Member Name: {0}.{1}", member.DeclaringType.FullName, member.Name)
            Console.WriteLine("   Message: {0}", attrib.Message)             
            Console.WriteLine("   Warning/Error: {0}", if(attrib.IsError, "Error", "Warning"))      
            n += 1
         End If
      Next
      
      If n = 0 Then
         Console.WriteLine("The Example type has no obsolete attributes.")
      End If 
   End Sub  
End Module
' The example displays the following output:
'       Obsolete members in the Example class:
'       
'       Member Name: Example.OldMethod
'          Message: This method is obsolete. Call NewMethod instead.
'          Warning/Error: Error
'       Member Name: Example.OldProperty
'          Message: This property is obsolete. Use NewProperty instead.
'          Warning/Error: Warning