C# Type.GetConstructors()用法及代碼示例

Type.GetConstructors() 方法用於獲取 Type 對象的構造函數。該方法的重載列表中有2個方法如下：

Type.GetConstructors() Method

此方法用於返回為當前 Type 定義的所有公共構造函數。
用法:

public System.Reflection.ConstructorInfo[] GetConstructors ();

返回值：該方法返回 ConstructorInfo 數組對象，表示為當前 Type 定義的所有公共實例構造函數，但不包括類型初始化器(靜態構造函數)。以下示例程序旨在說明 Type.GetConstructors() 方法的使用：示例 1：

C#


// C# program to demonstrate the
// Type.GetConstructors() Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
    // Main Method
    public static void Main()
    {
        // Declaring and initializing object
        object obj = new Object();
        // Getting the type of object
        // using GetType() method
        Type type = obj.GetType();
        // Getting constructors of the current Type.
        // using GetArrayRank() Method
        ConstructorInfo[] info = type.GetConstructors();
        // Display all the public instance constructors
        Console.WriteLine("All constructors are shown below");
        for (int i = 0; i < info.Length; i++)
            Console.WriteLine(info[i]);
    }
}

輸出：

All constructors are shown below
Void .ctor()

範例2：

C#


// C# program to demonstrate the
// Type.GetConstructors() Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
    // Main Method
    public static void Main()
    {
        // Declaring and initializing Type object
        Type type = typeof(string);
        // Getting constructors of the current Type.
        // using GetConstructors() Method
        ConstructorInfo[] info = type.GetConstructors();
        // Display all the public instance constructors
        Console.WriteLine("All constructors are shown below");
        for (int i = 0; i < info.Length; i++)
            Console.WriteLine(info[i]);
    }
}

輸出：

All constructors are shown below
Void .ctor(Char[])
Void .ctor(Char[], Int32, Int32)
Void .ctor(Char*)
Void .ctor(Char*, Int32, Int32)
Void .ctor(SByte*)
Void .ctor(SByte*, Int32, Int32)
Void .ctor(SByte*, Int32, Int32, Encoding)
Void .ctor(Char, Int32)
Void .ctor(ReadOnlySpan`1)

Type.GetConstructors(BindingFlags) Method

此方法用於返回為當前類型定義的構造函數，在派生類中重寫時使用指定的 BindingFlags，
用法:

public abstract System.Reflection.ConstructorInfo[] GetConstructors (System.Reflection.BindingFlags bindingAttr);

在這裏，它需要一個位掩碼，該位掩碼由一個或多個 BindingFlags 組成，指定在哪個點進行參加。或零，返回空值。
下麵是一些 BindingFlags 過濾器標誌，可用於定義要在搜索中包含哪些構造函數：

您必須指定 BindingFlags.Instance 或 BindingFlags.Static 才能獲得返回。
指定 BindingFlags.Public 以在搜索中包含公共構造函數。
指定 BindingFlags.NonPublic 以在搜索中包括非公共構造函數(即私有、內部和受保護的構造函數)。不返回基類的構造函數。

返回值：此方法返回一個 ConstructorInfo 對象數組，表示為當前 Type 定義的與指定綁定約束匹配的所有構造函數，包括類型初始值設定項(如果已定義)。以下示例程序旨在說明上述方法的使用：示例 1：

C#


// C# program to demonstrate the
// Type.GetConstructors(BindingFlags)
// Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
    // Main Method
    public static void Main()
    {
        // Declaring and initializing Type object
        Type type = typeof(string);
        // Declaring and initializing BindingFlags
        // it is used to specify how the search
        // is conducted
        BindingFlags bf = BindingFlags.Public
                          | BindingFlags.Static
                          | BindingFlags.NonPublic
                          | BindingFlags.Instance;
        // Getting constructors of the current Type.
        // using GetConstructors() Method
        ConstructorInfo[] info = type.GetConstructors(bf);
        // Display all constructors
        Console.WriteLine("All constructors are shown below");
        for (int i = 0; i < info.Length; i++)
            Console.WriteLine(info[i]);
    }
}

輸出：

All constructors are shown below
Void .ctor(Char[])
Void .ctor(Char[], Int32, Int32)
Void .ctor(Char*)
Void .ctor(Char*, Int32, Int32)
Void .ctor(SByte*)
Void .ctor(SByte*, Int32, Int32)
Void .ctor(SByte*, Int32, Int32, Encoding)
Void .ctor(Char, Int32)
Void .ctor(ReadOnlySpan`1)

範例2：

C#


// C# program to demonstrate the
// Type.GetConstructors(BindingFlags)
// Method
using System;
using System.Globalization;
using System.Reflection;
class GFG {
    // Main Method
    public static void Main()
    {
        // Creating and initializing object
        object obj = new Object();
        // Declaring and initializing Type object
        Type type = obj.GetType();
        // Declaring and initializing BindingFlags
        // it is used to specify how the search is conducted
        BindingFlags bf = BindingFlags.Public
                          | BindingFlags.Static
                          | BindingFlags.NonPublic
                          | BindingFlags.Instance;
        // Getting constructors of the current Type.
        // using GetConstructors() Method
        ConstructorInfo[] info = type.GetConstructors(bf);
        // Display all constructors
        Console.WriteLine("All constructors are shown below");
        for (int i = 0; i < info.Length; i++)
            Console.WriteLine(info[i]);
    }
}

輸出：

All constructors are shown below
Void .ctor()

參考：

https://docs.microsoft.com/en-us/dotnet/api/system.type.getconstructors?view=netcore-3.0

相關用法

注：本文由純淨天空篩選整理自RohitPrasad3大神的英文原創作品 Type.GetConstructors() Method in C# with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。