添加项目文件。

Class1.cs

@@ -0,0 +1,9 @@
+using System;
+
+namespace Virtual_PLC
+{
+    public class Class1
+    {
+
+    }
+}

Virtual PLC.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.2.32630.192
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Virtual_PLC", "Virtual_PLC.csproj", "{475F6CDB-E76D-404F-B5ED-3587A861E73A}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{475F6CDB-E76D-404F-B5ED-3587A861E73A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{475F6CDB-E76D-404F-B5ED-3587A861E73A}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{475F6CDB-E76D-404F-B5ED-3587A861E73A}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{475F6CDB-E76D-404F-B5ED-3587A861E73A}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {2E2F3422-506B-4F86-9F08-01FE3D1E7B76}
+	EndGlobalSection
+EndGlobal

Virtual_PLC.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+    <RootNamespace>Virtual_PLC</RootNamespace>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>