C# |类型。等熵定义()方法
原文:https://www . geesforgeks . org/c-sharp-type-isenumdefined-method/
类型。IsEnumDefined(Object)方法用于返回一个值，该值指示当前枚举类型中是否存在指定的值。
语法:公共虚拟 bool IsEnumDefined(对象值)； 在这里，需要对价值进行检验。
返回值:如果指定的值是当前枚举类型的成员，该方法返回 true ，否则返回 false。
异常:
- 参数异常:如果当前类型不是枚举。
- ArgumentNullException :如果值为空。
- 无效操作异常:如果值的类型不能是枚举的基础类型。
以下程序说明了类型的使用。等熵定义(对象)方法:
例 1:
// C# program to demonstrate the
// Type.IsEnumDefined(Object) Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
// defining enum enu
public enum enu {A, B, C};
// Main Method
public static void Main()
{
// try-catch block for handling Exception
try {
// creating and initializing object Type
object value = enu.A;
// checking for the current enumeration type
// by using IsEnumDefined() Method
bool status = typeof(enu).IsEnumDefined(value);
// display the result
if (status)
Console.WriteLine("specified value is a member"+
" of the current enumeration type");
else
Console.WriteLine("specified value is not"+
" present in the current enumeration type");
}
// catch ArgumentNullException here
catch (ArgumentNullException e) {
Console.WriteLine("Object is null.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
// catch ArgumentNullException here
catch (InvalidOperationException e) {
Console.WriteLine("Object is null.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
// catch ArgumentException here
catch (ArgumentException e) {
Console.WriteLine("Object is null.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
}
}
Output:
specified value is a member of the current enumeration type
例 2:
// C# program to demonstrate the
// Type.IsEnumDefined(Object) Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
// defining enum enu
public enum enu {A, B, C};
// Main Method
public static void Main()
{
// try-catch block for handling Exception
try {
// creating and initializing object Type
object value = enu.B;
// checking for the current enumeration type
// by using IsEnumDefined() Method
bool status = typeof(int).IsEnumDefined(value);
// display the result
if (status)
Console.WriteLine("specified value is a member"+
" of the current enumeration type");
else
Console.WriteLine("specified value is not"+
" present in the current enumeration type");
}
// catch ArgumentNullException here
catch (ArgumentNullException e) {
Console.WriteLine("value is null.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
// catch ArgumentException here
catch (ArgumentException e) {
Console.WriteLine("The current type is not an enumeration.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
}
}
Output:
The current type is not an enumeration.
Exception Thrown: System.ArgumentException
例 3:
// C# program to demonstrate the
// Type.IsEnumDefined(Object) Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
// defining enum enu
public enum enu {A, B, C};
// Main Method
public static void Main()
{
// try-catch block for handling Exception
try {
// creating and initializing object Type
object value = null;
// checking for the current enumeration type
// by using IsEnumDefined() Method
bool status = typeof(enu).IsEnumDefined(value);
// display the result
if (status)
Console.WriteLine("specified value is a member"+
" of the current enumeration type");
else
Console.WriteLine("specified value is not"+
" present in the current enumeration type");
}
// catch ArgumentNullException here
catch (ArgumentNullException e) {
Console.WriteLine("value is null.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
// catch ArgumentException here
catch (ArgumentException e) {
Console.WriteLine("The current type is not an enumeration.");
Console.Write("Exception Thrown: ");
Console.Write("{0}", e.GetType(), e.Message);
}
}
}
Output:
value is null.
Exception Thrown: System.ArgumentNullException
参考:
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