namespace WinFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Text = this.Width + "x" + this.Height + " pic "+ pictureBox1.Width + "x" + pictureBox1.Height + 启动环境(); 

        }

        public static string 启动环境()
        {
#if NET461
            return (".NET Framework 4.6.1");
#elif NET6_0
            return (".NET6");
#endif  
        }

    }
}

	<application xmlns="urn:schemas-microsoft-com:asm.v3">
		<windowsSettings>
			<dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true</dpiAware>
			<longPathAware xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">true</longPathAware>
		</windowsSettings>
	</application>

<Project Sdk="Microsoft.NET.Sdk">

	<PropertyGroup>
		<OutputType>WinExe</OutputType>
		<TargetFrameworks>net6.0-windows;net461;</TargetFrameworks>
		<UseWindowsForms>true</UseWindowsForms>
		<ApplicationManifest>app.manifest</ApplicationManifest>
		<ApplicationVisualStyles>true</ApplicationVisualStyles>
		<ApplicationUseCompatibleTextRendering>false</ApplicationUseCompatibleTextRendering>
		<ApplicationHighDpiMode>SystemAware</ApplicationHighDpiMode>
	</PropertyGroup>

	<ItemGroup>
		<Compile Update="Properties\Resources.Designer.cs">
			<DesignTime>True</DesignTime>
			<AutoGen>True</AutoGen>
			<DependentUpon>Resources.resx</DependentUpon>
		</Compile>
	</ItemGroup>

	<ItemGroup>
		<EmbeddedResource Update="Properties\Resources.resx">
			<Generator>ResXFileCodeGenerator</Generator>
			<LastGenOutput>Resources.Designer.cs</LastGenOutput>
		</EmbeddedResource>
	</ItemGroup>
</Project>

using System;
using System.Windows.Forms;

public Form1()
{
    AutoScaleMode = AutoScaleMode.Dpi; //添加这句,要在'InitializeComponent();'上方
    InitializeComponent();
}