代码生成器的原理无非就是得到字段相关信息（字段名，字段类型，字段注释等），然后根据模板，其实就是字符串的拼接与替换生成相应代码。

所以第一步我们需要解决如何得到字段的相关信息，有两种方式

• 通过反射获得程序集类的字段相关信息
• 读取数据库得到表的字段的相关信息

1. 新建一个.NET Core控制台项目 取名AbpCodeGenerator

   

2. 新建类DocsByReflection

    /// <summary>
       /// Utility class to provide documentation for various types where available with the assembly
       /// </summary>
       public class DocsByReflection
       {
           /// <summary>
           /// Provides the documentation comments for a specific method
           /// </summary>
           /// <param name="methodInfo">The MethodInfo (reflection data ) of the member to find documentation for</param>
           /// <returns>The XML fragment describing the method</returns>
           public static XmlElement XMLFromMember(MethodInfo methodInfo)
           {
               // Calculate the parameter string as this is in the member name in the XML
               string parametersString = "";
               foreach (ParameterInfo parameterInfo in methodInfo.GetParameters())
               {
                   if (parametersString.Length > 0)
                   {
                       parametersString += ",";
                   }
   
                   parametersString += parameterInfo.ParameterType.FullName;
               }
   
               //AL: 15.04.2008 ==> BUG-FIX remove ?)?if parametersString is empty
               if (parametersString.Length > 0)
                   return XMLFromName(methodInfo.DeclaringType, 'M', methodInfo.Name + "(" + parametersString + ")");
               else
                   return XMLFromName(methodInfo.DeclaringType, 'M', methodInfo.Name);
           }
   
           /// <summary>
           /// Provides the documentation comments for a specific member
           /// </summary>
           /// <param name="memberInfo">The MemberInfo (reflection data) or the member to find documentation for</param>
           /// <returns>The XML fragment describing the member</returns>
           public static XmlElement XMLFromMember(MemberInfo memberInfo)
           {
               // First character [0] of member type is prefix character in the name in the XML
               return XMLFromName(memberInfo.DeclaringType, memberInfo.MemberType.ToString()[0], memberInfo.Name);
           }
   
           /// <summary>
           /// Provides the documentation comments for a specific type
           /// </summary>
           /// <param name="type">Type to find the documentation for</param>
           /// <returns>The XML fragment that describes the type</returns>
           public static XmlElement XMLFromType(Type type)
           {
               // Prefix in type names is T
               return XMLFromName(type, 'T', "");
           }
   
           /// <summary>
           /// Obtains the XML Element that describes a reflection element by searching the 
           /// members for a member that has a name that describes the element.
           /// </summary>
           /// <param name="type">The type or parent type, used to fetch the assembly</param>
           /// <param name="prefix">The prefix as seen in the name attribute in the documentation XML</param>
           /// <param name="name">Where relevant, the full name qualifier for the element</param>
           /// <returns>The member that has a name that describes the specified reflection element</returns>
           private static XmlElement XMLFromName(Type type, char prefix, string name)
           {
               string fullName;
   
               if (String.IsNullOrEmpty(name))
               {
                   fullName = prefix + ":" + type.FullName;
               }
               else
               {
                   fullName = prefix + ":" + type.FullName + "." + name;
               }
   
               XmlDocument xmlDocument = XMLFromAssembly(type.Assembly);
   
               XmlElement matchedElement = null;
   
               foreach (XmlElement xmlElement in xmlDocument["doc"]["members"])
               {
                   if (xmlElement.Attributes["name"].Value.Equals(fullName))
                   {
                       if (matchedElement != null)
                       {
                           throw new DocsByReflectionException("Multiple matches to query", null);
                       }
   
                       matchedElement = xmlElement;
                       break;
                   }
               }
   
               if (matchedElement == null)
               {
                   throw new DocsByReflectionException("Could not find documentation for specified element", null);
               }
   
               return matchedElement;
           }
   
           /// <summary>
           /// A cache used to remember Xml documentation for assemblies
           /// </summary>
           static Dictionary<Assembly, XmlDocument> cache = new Dictionary<Assembly, XmlDocument>();
   
           /// <summary>
           /// A cache used to store failure exceptions for assembly lookups
           /// </summary>
           static Dictionary<Assembly, Exception> failCache = new Dictionary<Assembly, Exception>();
   
           /// <summary>
           /// Obtains the documentation file for the specified assembly
           /// </summary>
           /// <param name="assembly">The assembly to find the XML document for</param>
           /// <returns>The XML document</returns>
           /// <remarks>This version uses a cache to preserve the assemblies, so that 
           /// the XML file is not loaded and parsed on every single lookup</remarks>
           public static XmlDocument XMLFromAssembly(Assembly assembly)
           {
               if (failCache.ContainsKey(assembly))
               {
                   throw failCache[assembly];
               }
   
               try
               {
   
                   if (!cache.ContainsKey(assembly))
                   {
                       // load the docuemnt into the cache
                       cache[assembly] = XMLFromAssemblyNonCached(assembly);
                   }
   
                   return cache[assembly];
               }
               catch (Exception exception)
               {
                   failCache[assembly] = exception;
                   throw exception;
               }
           }
   
           /// <summary>
           /// Loads and parses the documentation file for the specified assembly
           /// </summary>
           /// <param name="assembly">The assembly to find the XML document for</param>
           /// <returns>The XML document</returns>
           private static XmlDocument XMLFromAssemblyNonCached(Assembly assembly)
           {
               string assemblyFilename = assembly.CodeBase;
   
               const string prefix = "file:///";
   
               if (assemblyFilename.StartsWith(prefix))
               {
                   using (StreamReader streamReader = new StreamReader(Path.ChangeExtension(assemblyFilename.Substring(prefix.Length), ".xml")))
                   {
                       XmlDocument xmlDocument = new XmlDocument();
                       xmlDocument.Load(streamReader);
   
                       return xmlDocument;
                   }
               }
               else
               {
                   throw new DocsByReflectionException("Could not ascertain assembly filename", null);
               }
           }
       }
   
       /// <summary>
       /// An exception thrown by the DocsByReflection library
       /// </summary>
       [Serializable]
       class DocsByReflectionException : Exception
       {
           /// <summary>
           /// Initializes a new exception instance with the specified
           /// error message and a reference to the inner exception that is the cause of
           /// this exception.
           /// </summary>
           /// <param name="message">The error message that explains the reason for the exception.</param>
           /// <param name="innerException">The exception that is the cause of the current exception, or null if none.</param>
           public DocsByReflectionException(string message, Exception innerException)
               : base(message, innerException)
           {
   
           }
       }

3. 新建类MetaTableInfo

    public class MetaTableInfo
       {
           /// <summary>
           /// 类的注释
           /// </summary>
           public string ClassAnnotation { get; set; }
   
           /// <summary>
           /// 属性名称
           /// </summary>
           public string Name { get; set; }
   
           /// <summary>
           /// 属性类型
           /// </summary>
           public string PropertyType { get; set; }
   
           /// <summary>
           /// 属性注释
           /// </summary>
           public string Annotation { get; set; }
   
   
   
           /// <summary>
           /// 根据类名 反射得到类的信息
           /// </summary>
           /// <param name="className">类名</param>
           /// <returns></returns>
           public static List<MetaTableInfo> GetMetaTableInfoListForAssembly(string className)
           {
   
               var list = new List<MetaTableInfo>();
               //读取的程序集路径 需换成自己项目的下的程序集路径
               string sourceAssemblyPath = "D:\\Project\\ZhouDaFu.XinYunFen.Core\\bin\\Debug\\netcoreapp2.0\\ZhouDaFu.XinYunFen.Core.dll";
               Type[] types = Assembly.LoadFrom(sourceAssemblyPath).GetTypes();
               foreach (var type in types)
               {
                   if (type.Name.Equals(className))
                   {
                       var classAnnotation = string.Empty;
                       try
                       {
                           //获取类的注释
                           XmlElement xmlFromType = DocsByReflection.XMLFromType(type.GetTypeInfo());
                           classAnnotation = xmlFromType["summary"].InnerText.Trim();
                       }
                       catch
                       {
   
   
                       }
   
                       foreach (PropertyInfo properties in type.GetProperties())
                       {
                           var metaTableInfo = new MetaTableInfo();
                           try
                           {
                               XmlElement documentation = DocsByReflection.XMLFromMember(type.GetProperty(properties.Name));
                               metaTableInfo.Annotation = documentation["summary"].InnerText.Trim();
   
                               metaTableInfo.ClassAnnotation = classAnnotation;
                           }
                           catch
                           {
                               metaTableInfo.Annotation = "";
                           }
                           metaTableInfo.Name = properties.Name;
                           if (properties.PropertyType == typeof(int))
                           {
                               metaTableInfo.PropertyType = "int";
                           }
                           else if (properties.PropertyType == typeof(int?))
                           {
                               metaTableInfo.PropertyType = "int?";
                           }
                           else if (properties.PropertyType == typeof(long))
                           {
                               metaTableInfo.PropertyType = "long";
                           }
                           else if (properties.PropertyType == typeof(long?))
                           {
                               metaTableInfo.PropertyType = "long?";
                           }
                           else if (properties.PropertyType == typeof(DateTime?))
                           {
                               metaTableInfo.PropertyType = "DateTime?";
                           }
                           else if (properties.PropertyType == typeof(decimal))
                           {
                               metaTableInfo.PropertyType = "decimal";
                           }
                           else if (properties.PropertyType == typeof(decimal?))
                           {
                               metaTableInfo.PropertyType = "decimal?";
                           }
                           else if (properties.PropertyType == typeof(string))
                           {
                               metaTableInfo.PropertyType = "string";
                           }
                           else if (properties.PropertyType == typeof(bool))
                           {
                               metaTableInfo.PropertyType = "bool";
                           }
                           else
                           {
                               metaTableInfo.PropertyType = properties.PropertyType.ToString().Split('.').Last().Replace("]", "");
                           }
                           list.Add(metaTableInfo);
                       }
                   }
               }
   
               return list;
           }
   
   
       }

4. 在Program类中添加如下代码

   //反射程序集的方式生成相应代码 
               string className = "User";//跟类名保持一致
               var metaTableInfoList = MetaTableInfo.GetMetaTableInfoListForAssembly(className);

   启动控制台，获得User相关信息，报如下错误

   

   这是缺少ABP相关程序集引用，使用NuGet安装如下程序集

   

5. 启动控制台得到如下结果，剩下的就是字符串拼接了

   

6. 新建一个txt文件模板（直接在代码里面拼接字符串也行，只不过那样修改起来麻烦），取名IndexJsTemplate.txt，添加如下代码

   (function () {
       $(function () {
   
           var _${{entity_Name_Plural_Here}}Table = $('#MainTable');
           var _{{entity_Name_Plural_Here}}Service = abp.services.app.{{entity_Name_Plural_Here}};
   
           var _permissions = {
               create: abp.auth.hasPermission('{{Permission_Value_Here}}.Create'),
               edit: abp.auth.hasPermission('{{Permission_Value_Here}}.Edit'),
               'delete': abp.auth.hasPermission('{{Permission_Value_Here}}.Delete')
           };
   
           var _createOrEditModal = new app.ModalManager({
               viewUrl: abp.appPath + '{{App_Area_Name_Here}}/{{Entity_Name_Plural_Here}}/CreateOrEditModal',
               scriptUrl: abp.appPath + 'view-resources/Areas/{{App_Area_Name_Here}}/Views/{{Entity_Name_Plural_Here}}/_CreateOrEditModal.js',
               modalClass: 'CreateOrEdit{{Entity_Name_Here}}Modal'
           });
   
           var dataTable = _${{entity_Name_Plural_Here}}Table.DataTable({
               paging: true,
               serverSide: true,
               processing: true,
               listAction: {
                   ajaxFunction: _{{entity_Name_Plural_Here}}Service.getAll,
                   inputFilter: function () {
                       return {
                    filter: $('#{{Entity_Name_Plural_Here}}TableFilter').val()
                       };
                   }
               },
               columnDefs: [
                   {
                       width: 120,
                       targets: 0,
                       data: null,
                       orderable: false,
                       autoWidth: false,
                       defaultContent: '',
                       rowAction: {
                           cssClass: 'btn btn-brand dropdown-toggle',
                           text: '<i class="fa fa-cog"></i> ' + app.localize('Actions') + ' <span class="caret"></span>',
                           items: [
                        {
                               text: app.localize('Edit'),
                               visible: function () {
                                   return _permissions.edit;
                               },
                               action: function (data) {
                                   _createOrEditModal.open({ id: data.record.id });
                               }
                           }, {
                               text: app.localize('Delete'),
                               visible: function () {
                                   return _permissions.delete;
                               },
                               action: function (data) {
                                   delete{{Entity_Name_Here}}(data.record);
                               }
                           }]
                       }
                   }{{Property_Looped_Template_Here}}
               ]
           });
   
   
           function get{{Entity_Name_Plural_Here}}() {
               dataTable.ajax.reload();
           }
   
           function delete{{Entity_Name_Here}}({{entity_Name_Here}}) {
               abp.message.confirm(
                   '',
                   function (isConfirmed) {
                       if (isConfirmed) {
                           _{{entity_Name_Plural_Here}}Service.delete({
                               id: {{entity_Name_Here}}.id
                           }).done(function () {
                               get{{Entity_Name_Plural_Here}}(true);
                               abp.notify.success(app.localize('SuccessfullyDeleted'));
                           });
                       }
                   }
               );
           }
   
        $('#Export{{Entity_Name_Here}}ToExcelButton').click(function () {
               _{{entity_Name_Here}}Service
                   .get{{Entity_Name_Here}}ToExcel({})
                   .done(function (result) {
                       app.downloadTempFile(result);
                   });
           });
   
           $('#CreateNew{{Entity_Name_Here}}Button').click(function () {
               _createOrEditModal.open();
           });
   
           abp.event.on('app.createOrEdit{{Entity_Name_Here}}ModalSaved', function () {
               get{{Entity_Name_Plural_Here}}();
           });
   
        $('#Get{{Entity_Name_Plural_Here}}Button').click(function (e) {
               e.preventDefault();
               get{{Entity_Name_Plural_Here}}();
           });
   
        $(document).keypress(function(e) {
          if(e.which === 13) {
            get{{Entity_Name_Plural_Here}}();
          }
        });
   
       });
   })();

7. 首先读取文件模板，然后去替换掉“{{}}” 这种类似占位符的变量，然后再输出一个新的文件，代码如下

    static void Main(string[] args)
           {
               //反射程序集的方式生成相应代码 
               string className = "User";//跟类名保持一致
               var metaTableInfoList = MetaTableInfo.GetMetaTableInfoListForAssembly(className);
               SetIndexJsTemplate(className, metaTableInfoList);
           }
   
   
           /// <summary>
           /// 生成IndexJsTemplate
           /// </summary>
           /// <param name="className"></param>
           public static void SetIndexJsTemplate(string className, List<MetaTableInfo> metaTableInfoList)
           {
               var rootPath = (Directory.GetCurrentDirectory().Split(new string[] { "bin" }, StringSplitOptions.RemoveEmptyEntries))[0];
               string templateContentDirectory = rootPath + "IndexJsTemplate.txt";
               var templateContent = Read(templateContentDirectory);
   
               StringBuilder sb = new StringBuilder();
               var i = 1;
               foreach (var item in metaTableInfoList)
               {
                   sb.AppendLine(", {");
                   sb.AppendLine("targets: " + i + ",");
                   sb.AppendLine("data: \"" + GetFirstToLowerStr(item.Name) + "\"");
                   sb.AppendLine("}");
                   i++;
               }
               var property_Looped_Template_Here = sb.ToString();
               templateContent = templateContent
                                                .Replace("{{Entity_Name_Plural_Here}}", className)
                                                .Replace("{{Entity_Name_Here}}", className)
                                                .Replace("{{entity_Name_Here}}", GetFirstToLowerStr(className))
                                                .Replace("{{entity_Name_Plural_Here}}", GetFirstToLowerStr(className))
                                                .Replace("{{App_Area_Name_Here}}", "App_Area_Name")
                                                .Replace("{{Property_Looped_Template_Here}}", property_Looped_Template_Here)
                                                .Replace("{{Permission_Value_Here}}", "Pages.Administration." + className + "")
                                                ;
               Write(rootPath, "Index.js", templateContent);
           }
   
   
   
           #region 文件读取
           public static string Read(string path)
           {
               using (StreamReader sr = new StreamReader(path, Encoding.Default))
               {
                   StringBuilder sb = new StringBuilder();
   
                   String line;
                   while ((line = sr.ReadLine()) != null)
                   {
                       sb.AppendLine(line.ToString());
                   }
                   return sb.ToString();
               }
           }
   
           /// <summary>
           /// 
           /// </summary>
           /// <param name="filePath">文件保存路径</param>
           /// <param name="fileName">文件名</param>
           /// <param name="templateContent">模板内容</param>
           public static void Write(string filePath, string fileName, string templateContent)
           {
               if (!Directory.Exists(filePath))
               {
                   Directory.CreateDirectory(filePath);
               }
               using (FileStream fs = new FileStream(filePath + fileName, FileMode.Create))
               {
                   //获得字节数组
                   byte[] data = Encoding.Default.GetBytes(templateContent);
                   //开始写入
                   fs.Write(data, 0, data.Length);
               }
   
           }
   
           /// <summary>
           /// 
           /// </summary>
           /// <param name="filePath">文件保存路径</param>
           /// <param name="templateContent">模板内容</param>
           public static void Write(string filePath, string templateContent)
           {
               using (FileStream fs = new FileStream(filePath, FileMode.Create))
               {
                   //获得字节数组
                   byte[] data = Encoding.Default.GetBytes(templateContent);
                   //开始写入
                   fs.Write(data, 0, data.Length);
               }
   
           }
           #endregion
   
           #region 首字母小写
           /// <summary>
           /// 首字母小写
           /// </summary>
           /// <param name="s"></param>
           /// <returns></returns>
           public static string GetFirstToLowerStr(string str)
           {
               if (!string.IsNullOrEmpty(str))
               {
                   if (str.Length > 1)
                   {
                       return char.ToLower(str[0]) + str.Substring(1);
                   }
                   return char.ToLower(str[0]).ToString();
               }
               return null;
           }
           #endregion
       }

8. 启动控制台，即在当前项目下生成相应代码，这里分享一个我之前写好的基于abp.zero core 5.3.0的

   https://github.com/HisKingdom/CodeGenerator