typeof(C# 參考)
用於獲取類型的 System.Type 對象。typeof 表達式采用以下形式:
System.Type type = typeof(int);
備注
若要獲取表達式的運行時類型,可以使用 .NET Framework 方法 GetType,如下所示:
int i = 0; System.Type type = i.GetType();
typeof 運算符也能用於公開的泛型類型。具有不止一個類型參數的類型的規范中必須有適當數量的逗號。不能重載 typeof 運算符。
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示例
// cs_operator_typeof.cs
using
System;
using
System.Reflection;
public
class SampleClass
{
public
int sampleMember;
public
void SampleMethod() {}
static
void Main()
{
Type t =
typeof
(SampleClass);
// Alternatively, you could use
// SampleClass obj = new SampleClass();
// Type t = obj.GetType();
Console.WriteLine(
"Methods:"
);
MethodInfo[] methodInfo = t.GetMethods();
foreach
(MethodInfo mInfo in methodInfo)
Console.WriteLine(mInfo.ToString());
Console.WriteLine(
"Members:"
);
MemberInfo[] memberInfo = t.GetMembers();
foreach
(MemberInfo mInfo in memberInfo)
Console.WriteLine(mInfo.ToString());
}
}
輸出
Methods:
Void SampleMethod()
System.Type GetType()
System.String ToString()
Boolean Equals(System.Object)
Int32 GetHashCode()
Members:
Void SampleMethod()
System.Type GetType()
System.String ToString()
Boolean Equals(System.Object)
Int32 GetHashCode()
Void .ctor()
Int32 sampleMember
此示例使用 GetType 方法確定用來包含數值計算的結果的類型。這取決於結果數字的存儲要求。
// cs_operator_typeof2.cs
using
System;
class
GetTypeTest
{
static
void Main()
{
int
radius = 3;
Console.WriteLine(
"Area = {0}"
, radius * radius * Math.PI);
Console.WriteLine(
"The type is {0}"
,
(radius * radius * Math.PI).GetType()
);
}
}
輸出
Area = 28.2743338823081
The type
is
System.Double
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