ObsoleteAttribute.IsError 屬性

定義

命名空間:

System

組件:

System.Runtime.dll

組件:

mscorlib.dll

組件:

netstandard.dll

取得值，其指出編譯器是否會將使用過時的程式元素視為錯誤。

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

public bool IsError { get; }

member this.IsError : bool

Public ReadOnly Property IsError As Boolean

屬性值

Boolean

如果使用已過時項目視為錯誤，則為 true，否則為 false。 預設為 false。

範例

下列範例會定義類別，其中包含標示為過時的兩個成員。 第一個名為 的屬性 OldProperty 會在呼叫時產生編譯器警告。 第二個是名為 CallOldMethod 的方法，會產生編譯器錯誤。 此範例會使用反映來取得套用至類型成員的屬性相關資訊 ObsoleteAttribute ，並顯示其 Message 和 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   [ObsoleteAttribute("This property is obsolete.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   [ObsoleteAttribute("This method is obsolete.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//          Message: This method is obsolete.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