在不使用 unsafe 的情况下在 C# 中处理 C++ 指针的最佳方法

Question

In my case , I have bunch of values of same type , let's say floats :

        float value1 = 1.2f;
        float value2 = 1.5f;
        float value3 = 2.3f;

Now I need a pointer or a reference value can get a instance of this floats and do operations on it.

in C++ :

    float* float_reference;

Now I want to set float_reference to value1 So in my functions every computation put result in value1.

Notes : - I don't want to use classes - I don't want to use ref keyword in a functions - I don't want to use unsafe keyword

I just need to do it as I said like C++ , Is there any other way around ?

EDIT 1 : This is why I can't use unsafe , Here's Example :

using System.Windows;


namespace ValueUpdater
{

    public unsafe partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            //// need to assign one of floats to reference object
        }

        float value1 = 1.2f;
        float value2 = 1.5f;
        float value3 = 2.3f;

        float* value_ref; ////// Can't Make this pointer!

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            /// Need to change the reference here
            fixed (float* value_ref = &value3) {
                *value_ref += 2;
            };
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            /// Need to change the reference here
            /// But can't use value_ref = &value3 without re-initalize
             fixed (float* value_ref = &value3)
            {
                *value_ref -= 2;
            };

        }

        private void Button_Click_2(object sender, RoutedEventArgs e)
        {
            Output.Content = value3.ToString();
        }
    }
}

XAML :

<Window x:Class="ValueUpdater.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ValueUpdater"
        mc:Ignorable="d"
        Title="MainWindow" Height="354.017" Width="368.698">
    <Grid>
        <Button Content="Add 2" Margin="0,28,27,0" VerticalAlignment="Top" HorizontalAlignment="Right" Width="75" Click="Button_Click"/>
        <Button Content="Sub 2" Margin="0,55,27,0" VerticalAlignment="Top" HorizontalAlignment="Right" Width="75" Click="Button_Click_1"/>
        <Button Content="Reset" Margin="0,83,27,0" VerticalAlignment="Top" HorizontalAlignment="Right" Width="75"/>
        <Button Content="Print" Margin="0,0,27,20" HorizontalAlignment="Right" Width="75" Height="20" VerticalAlignment="Bottom" Click="Button_Click_2"/>
        <Label x:Name="Output" Content="Output" HorizontalAlignment="Left" Margin="19,22,0,0" VerticalAlignment="Top" Width="182"/>

    </Grid>
</Window>

Answer 1

I don't want to use classes - I don't want to use ref keyword in a functions - I don't want to use unsafe keyword

Nope; those are the three options for conveying state in a reference-like way:

1. unmanaged pointers ( unsafe )
2. managed pointers ( ref )
3. indirectly as fields on a reference-type ( class )

You could also use indirection via an float[] array, Span<float> , or Memory<float> , but then you also need to convey the index; frankly, those are all just indirect ways of getting a managed pointer to a value, so they're really just special cases of "2".

Answer 2

The key usage in the question is this:

        float value1 = 1.2f;
        float value2 = 1.5f;
        float value3 = 2.3f;

        float* value_ref; ////// Can't Make this pointer!

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            fixed (float* value_ref = &value3) {
                *value_ref += 2;
            };
        }

        private void Button_Click_1(object sender, RoutedEventArgs e)
        {
            fixed (float* value_ref = &value3)
            {
                *value_ref -= 2;
            };

        }

In that code, you are always updating value3 . If we assume that this code is illustrative and that you intended to update indirectly via value_ref ; we can't keep a ref float as a field (even inside a ref struct ), so fundamentally, I think the best way to reconsider this is via an array, ie

float[] values = new [] {1.2f, 1.5f, 2.3f};
int value_index;

Now we can use:

values[value_index] += 2;
...
values[value_index] -= 2;

Not quite the same as the C++, but: very effective and simple.