Exception.ToString 方法

定義

建立並傳回目前例外狀況的字串表示。Creates and returns a string representation of the current exception.

public:
 override System::String ^ ToString();
public override string ToString ();
override this.ToString : unit -> string
Public Overrides Function ToString () As String

傳回

String

目前例外狀況的字串表示。A string representation of the current exception.

實作

範例

下列範例會造成例外狀況,並顯示對該例外狀況呼叫 ToString 的結果。The following example causes an exception and displays the result of calling ToString on that exception. 請注意,當 Exception 類別實例出現在 Console.WriteLine 方法的引數清單中時,會隱含地呼叫 Exception.ToString 方法。Note that the Exception.ToString method is called implicitly when the Exception class instance appears in the argument list of the Console.WriteLine method.

using namespace System;

public ref class TestClass{};

int main()
{
   TestClass^ test = gcnew TestClass;
   array<Object^>^ objectsToCompare = { test, test->ToString(), 123,
                                        (123).ToString(), "some text",
                                        "Some Text" };
   String^ s = "some text";
   for each (Object^ objectToCompare in objectsToCompare) {
      try {
         Int32 i = s->CompareTo(objectToCompare);
         Console::WriteLine("Comparing '{0}' with '{1}': {2}",
                            s, objectToCompare, i);
      }
      catch (ArgumentException^ e) {
            Console::WriteLine("Bad argument: {0} (type {1})",
                              objectToCompare,
                              objectToCompare->GetType()->Name);
            Console::WriteLine("Exception information: {0}", e);
      }
      Console::WriteLine();
   }
}
// The example displays the following output:
//     Bad argument: TestClass (type TestClass)
//     Exception information: System.ArgumentException: Object must be of type String.
//        at System.String.CompareTo(Object value)
//        at Example.Main()
//     
//     Comparing 'some text' with 'TestClass': -1
//     
//     Bad argument: 123 (type Int32)
//     Exception information: System.ArgumentException: Object must be of type String.
//        at System.String.CompareTo(Object value)
//        at Example.Main()
//     
//     Comparing 'some text' with '123': 1
//     
//     Comparing 'some text' with 'some text': 0
//     
//     Comparing 'some text' with 'Some Text': -1
using System;

public class TestClass
{}

public class Example
{
   public static void Main()
   {
      var test = new TestClass();
      Object[] objectsToCompare = { test, test.ToString(), 123,
                                    123.ToString(), "some text",
                                    "Some Text" };
      string s = "some text";
      foreach (var objectToCompare in objectsToCompare) {
         try {
            int i = s.CompareTo(objectToCompare);
            Console.WriteLine("Comparing '{0}' with '{1}': {2}",
                              s, objectToCompare, i);
         }
         catch (ArgumentException e) {
            Console.WriteLine("Bad argument: {0} (type {1})",
                              objectToCompare,
                              objectToCompare.GetType().Name);
            Console.WriteLine("Exception information: {0}", e);
         }
         Console.WriteLine();
      }
   }
}
// The example displays the following output:
//     Bad argument: TestClass (type TestClass)
//     Exception information: System.ArgumentException: Object must be of type String.
//        at System.String.CompareTo(Object value)
//        at Example.Main()
//
//     Comparing 'some text' with 'TestClass': -1
//
//     Bad argument: 123 (type Int32)
//     Exception information: System.ArgumentException: Object must be of type String.
//        at System.String.CompareTo(Object value)
//        at Example.Main()
//
//     Comparing 'some text' with '123': 1
//
//     Comparing 'some text' with 'some text': 0
//
//     Comparing 'some text' with 'Some Text': -1
Public Class TestClass
End Class 

Public Class Example
   Public Shared Sub Main()
      Dim test As New TestClass()
      Dim objectsToCompare() As Object = { test, test.ToString(), 123,
                                           123.ToString(), "some text",
                                           "Some Text" }
      Dim s As String = "some text"
      For Each objectToCompare In objectsToCompare
         Try
            Dim i As Integer = s.CompareTo(objectToCompare)
            Console.WriteLine("Comparing '{0}' with '{1}': {2}",
                              s, objectToCompare, i)
         Catch e As ArgumentException
            Console.WriteLine("Bad argument: {0} (type {1})",
                              objectToCompare,
                              objectToCompare.GetType().Name)
            Console.WriteLine("Exception information: {0}", e)
         End Try
         Console.WriteLine()
      Next
   End Sub 
End Class 
' The example displays the following output:
'     Bad argument: TestClass (type TestClass)
'     Exception information: System.ArgumentException: Object must be of type String.
'        at System.String.CompareTo(Object value)
'        at Example.Main()
'     
'     Comparing 'some text' with 'TestClass': -1
'     
'     Bad argument: 123 (type Int32)
'     Exception information: System.ArgumentException: Object must be of type String.
'        at System.String.CompareTo(Object value)
'        at Example.Main()
'     
'     Comparing 'some text' with '123': 1
'     
'     Comparing 'some text' with 'some text': 0
'     
'     Comparing 'some text' with 'Some Text': -1

備註

ToString 會傳回目前例外狀況的表示方式,以供人類瞭解。ToString returns a representation of the current exception that is intended to be understood by humans. 其中,如果例外狀況包含區分文化特性的資料,ToString 所傳回的字串表示必須考慮目前的系統文化特性。Where the exception contains culture-sensitive data, the string representation returned by ToString is required to take into account the current system culture. 雖然傳回字串的格式沒有完全的需求,但它應該會嘗試反映使用者所見的物件值。Although there are no exact requirements for the format of the returned string, it should attempt to reflect the value of the object as perceived by the user.

ToString 的預設執行會取得擲回目前例外狀況的類別名稱、訊息、在內部例外狀況上呼叫 ToString 的結果,以及呼叫 Environment.StackTrace的結果。The default implementation of ToString obtains the name of the class that threw the current exception, the message, the result of calling ToString on the inner exception, and the result of calling Environment.StackTrace. 如果其中有任何成員 null,其值就不會包含在傳回的字串中。If any of these members is null, its value is not included in the returned string.

如果沒有錯誤訊息,或者它是空字串(""),則不會傳回任何錯誤訊息。If there is no error message or if it is an empty string (""), then no error message is returned. 內部例外狀況的名稱和堆疊追蹤只有在未 null時才會傳回。The name of the inner exception and the stack trace are returned only if they are not null.

這個方法會覆寫 Object.ToStringThis method overrides Object.ToString.

適用於