[C#]快速將字串轉換為結構

看到MSDN上請問將一個字串copy到一個結構中最快的方式為何?這篇的發問，做些紀錄：

要將字串快速轉換為結構，首先我們必須要在結構上加些Attribute，像是設定每個欄位所佔用的型態、大小…等： [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct MyStruct { [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 4)] public string fname; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 4)] public string lname; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 7)] public string phone; }

在轉換時先透過Marshal.StringToBSTR將字串轉為指標，再透過Marshal.PtrToStructure將指標轉換為指定的結構型態，最後再用Marshal.FreeBSTR把剛剛的指標位置給釋放掉就可以了：

private static T ConvertToStruct(string val) { IntPtr valPoint = Marshal.StringToBSTR(val); T ret = (T)Marshal.PtrToStructure(valPoint, typeof(T)); Marshal.FreeBSTR(valPoint); return ret; }

完整範例如下：

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.IO; using System.Runtime.InteropServices;

namespace ConsoleApplication20 { class Program { [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct MyStruct { [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 4)] public string fname; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 4)] public string lname; [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 7)] public string phone; }

private static T ConvertToStruct(string val) { IntPtr valPoint = Marshal.StringToBSTR(val); T ret = (T)Marshal.PtrToStructure(valPoint, typeof(T)); Marshal.FreeBSTR(valPoint); return ret; }

public static void Main() { MyStruct ms = ConvertToStruct(“abcdefgh2223333”); Console.WriteLine(“fname is: {0}”, ms.fname); Console.WriteLine(“lname is: {0}”, ms.lname); Console.WriteLine(“phone is: {0}”, ms.phone); } } }

運行後可以發現abcdefgh2223333字串會依照我們在結構欄位所設定的長度自動填入：

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How to copy a String into a struct using C#

請問將一個字串copy到一個結構中最快的方式為何?

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