C# 可否对内存进行直接的操作？

可以，用 unsafe。用的时候记得在项目属性(Properties)->生成(Build)->常规(General)中钩上允许不安全代码 (Allow unsafe code)。
否则会出现这个错误：Unsafe code may only appear if compiling with /unsafe。

// compile with: /unsafe

using System;
class UnsafeTest
{
// Unsafe method: takes pointer to int:
unsafe static void SquarePtrParam(int* p)
{
*p *= *p;
}

unsafe static void Main()
{
int i = 5;
// Unsafe method: uses address-of operator (&):
SquarePtrParam(&i);
Console.WriteLine(i);
}
}
// Output: 25

// compile with: /unsafe

using System;
class UnsafeTest
{
    // Unsafe method: takes pointer to int:
    unsafe static void SquarePtrParam(int* p)
    {
        *p *= *p;
    }

    unsafe static void Main()
    {
        int i = 5;
        // Unsafe method: uses address-of operator (&):
        SquarePtrParam(&i);
        Console.WriteLine(i);
    }
}
// Output: 25

// compile with: /unsafe

using System;
class UnsafeTest
{
    // Unsafe method: takes pointer to int:
    unsafe static void SquarePtrParam(int* p)
    {
        *p *= *p;
    }

    unsafe static void Main()
    {
        int i = 5;
        // Unsafe method: uses address-of operator (&):
        SquarePtrParam(&i);
        Console.WriteLine(i);
    }
}
// Output: 25