EnityFrameworkCore CodeFirst 根据实体注释自动生成字段描述

EF core中Code First时,没有提供根据注自动生成表字段的描述功能,SO上发现这个解决方案,而且正好在看ABP的使用,就放到ABP的Demo项目集成。这个方案适用于所有的EF core code first的情况。

操作步骤:

1. 添加SchemaDescriptionUpdater.cs类文件到EntityFrameworkCore的项目中,如下图

图1

2. 设置实体类所在项目的属性,点击项目右键-属性-生成 选中下面的选项,注意:路径中添加App_Data路径。

图2

3. 在包命令行中,输入Add-Migration,成功执行命令后会自动添加迁移的文件,把下面的代码复制其中。

  • 注意projectName需要替换成实体所在的项目名称
protected  override  void Up(MigrationBuilder migrationBuilder)

 {

  string projectName = "abpDemo.Core";

 SchemaDescriptionUpdater updater = new SchemaDescriptionUpdater(CreateDbContext(),

  $@"{Environment.CurrentDirectory.Substring(0, Environment.CurrentDirectory.LastIndexOf(@"\"))}\{projectName}\App_Data\{projectName}.xml");

 updater.UpdateDatabaseDescriptions();

 }

  protected  override  void Down(MigrationBuilder migrationBuilder)

 {

 }

  private abpDemoDbContext CreateDbContext()

 {

  var builder = new DbContextOptionsBuilder();

  var configuration = AppConfigurations.Get(WebContentDirectoryFinder.CalculateContentRootFolder());

 abpDemoDbContextConfigurer.Configure(builder, configuration.GetConnectionString("default"));

  return  new abpDemoDbContext(builder.Options);

 }

4. 然后执行Update Database 命令,字段注释的内容这时会更新到表的描述中。

5. SchemaDescriptionUpdater类中的代码


using Microsoft.Data.SqlClient;
using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Storage;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations.Schema;
using System.Data;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Text.RegularExpressions;
using System.Xml;

namespace EntityFrameworkCore.Extension
{
    /// 
    /// Based on below link to finished this solution
    /// https://stackoverflow.com/questions/10080601/how-to-add-description-to-columns-in-entity-framework-4-3-code-first-using-migra
    /// 
    /// 
    public class SchemaDescriptionUpdater where TContext : DbContext
    {
        private Type contextType;
        private TContext context;
        private IDbContextTransaction transaction;
        private XmlAnnotationReader reader;

        public SchemaDescriptionUpdater(TContext context)
        {
            this.context = context;
            reader = new XmlAnnotationReader();
        }

        public SchemaDescriptionUpdater(TContext context, string xmlDocumentationPath)
        {
            this.context = context;
            reader = new XmlAnnotationReader(xmlDocumentationPath);
        }

        public void UpdateDatabaseDescriptions()
        {
            contextType = typeof(TContext);
            var props = contextType.GetProperties(BindingFlags.Instance | BindingFlags.Public);
            transaction = null;
            try
            {
                context.Database.OpenConnection();
                transaction = context.Database.BeginTransaction();
                foreach (var prop in props)
                {
                    if (prop.PropertyType.InheritsOrImplements((typeof(DbSet<>))))
                    {
                        var tableType = prop.PropertyType.GetGenericArguments()[0];
                        SetTableDescriptions(tableType);
                    }
                }
                transaction.Commit();
            }
            catch
            {
                if (transaction != null)
                    transaction.Rollback();
                throw;
            }
            finally
            {
                context.Database.CloseConnection();
            }
        }

        private string GetTableName(Type tableType)
        {
            string tableName = tableType.Name;
            var customAttributes = tableType.GetCustomAttributes(typeof(TableAttribute), false);
            if (customAttributes.Count() > 0)
            {
                tableName = (customAttributes.First() as TableAttribute).Name;
            }

            return tableName;
        }

        private void SetTableDescriptions(Type tableType)
        {
            string fullTableName = GetTableName(tableType); //context.GetTableName(tableType);

            Regex regex = new Regex(@"(\[\w+\]\.)?\[(?.*)\]");
            Match match = regex.Match(fullTableName);
            string tableName;
            if (match.Success)
                tableName = match.Groups["table"].Value;
            else
                tableName = fullTableName;

            var tableAttrs = tableType.GetCustomAttributes(typeof(TableAttribute), false);
            if (tableAttrs.Length > 0)
                tableName = ((TableAttribute)tableAttrs[0]).Name;

            // set the description for the table
            string tableComment = reader.GetCommentsForResource(tableType, null, XmlResourceType.Type);
            if (!string.IsNullOrEmpty(tableComment))
                SetDescriptionForObject(tableName, null, tableComment);

            // get all of the documentation for each property/column
            ObjectDocumentation[] columnComments = reader.GetCommentsForResource(tableType);
            foreach (var column in columnComments)
            {
                SetDescriptionForObject(tableName, column.PropertyName, column.Documentation);
            }
        }

        private void SetDescriptionForObject(string tableName, string columnName, string description)
        {
            string strGetDesc = "";
            // determine if there is already an extended description
            if (string.IsNullOrEmpty(columnName))
                strGetDesc = "select top 1 CONVERT(varchar(max), [value]) from fn_listextendedproperty('MS_Description','schema','dbo','table',N'" + tableName + "',null,null)";
            else
                strGetDesc = "select top 1 CONVERT(varchar(max), [value]) from fn_listextendedproperty('MS_Description','schema','dbo','table',N'" + tableName + "','column',null) where objname = N'" + columnName + "'";
            var prevDesc = (string)RunSqlScalar(strGetDesc);

            var parameters = new List
            {
                new SqlParameter("@table", tableName),
                new SqlParameter("@desc", description)
            };

            // is it an update, or new?
            string funcName = "sp_addextendedproperty";
            if (!string.IsNullOrEmpty(prevDesc))
                funcName = "sp_updateextendedproperty";

            string query = @"EXEC " + funcName + @" @name = N'MS_Description', @value = @desc,@level0type = N'Schema', @level0name = 'dbo',@level1type = N'Table',  @level1name = @table";

            // if a column is specified, add a column description
            if (!string.IsNullOrEmpty(columnName))
            {
                parameters.Add(new SqlParameter("@column", columnName));
                query += ", @level2type = N'Column', @level2name = @column";
            }
            RunSql(query, parameters.ToArray());
        }

        private void RunSql(string cmdText, params SqlParameter[] parameters)
        {
            context.Database.ExecuteSqlRaw(cmdText, parameters);
        }

        private object RunSqlScalar(string cmdText)
        {
            var resultParameter = new SqlParameter("@result", SqlDbType.VarChar);
            resultParameter.Size = 2000;
            resultParameter.Direction = ParameterDirection.Output;

            context.Database.ExecuteSqlRaw($"set @result = ({cmdText})", resultParameter);
            return resultParameter.Value as string;
        }
    }

    public static class ReflectionUtil
    {
        public static bool InheritsOrImplements(this Type child, Type parent)
        {
            parent = ResolveGenericTypeDefinition(parent);

            var currentChild = child.IsGenericType
                                   ? child.GetGenericTypeDefinition()
                                   : child;

            while (currentChild != typeof(object))
            {
                if (parent == currentChild || HasAnyInterfaces(parent, currentChild))
                    return true;

                currentChild = currentChild.BaseType != null
                               && currentChild.BaseType.IsGenericType
                                   ? currentChild.BaseType.GetGenericTypeDefinition()
                                   : currentChild.BaseType;

                if (currentChild == null)
                    return false;
            }
            return false;
        }

        private static bool HasAnyInterfaces(Type parent, Type child)
        {
            return child.GetInterfaces()
                .Any(childInterface =>
                {
                    var currentInterface = childInterface.IsGenericType
                        ? childInterface.GetGenericTypeDefinition()
                        : childInterface;

                    return currentInterface == parent;
                });
        }

        private static Type ResolveGenericTypeDefinition(Type parent)
        {
            var shouldUseGenericType = true;
            if (parent.IsGenericType && parent.GetGenericTypeDefinition() != parent)
                shouldUseGenericType = false;

            if (parent.IsGenericType && shouldUseGenericType)
                parent = parent.GetGenericTypeDefinition();
            return parent;
        }
    }

    public class XmlAnnotationReader
    {
        public string XmlPath { get; protected internal set; }
        public XmlDocument Document { get; protected internal set; }

        public XmlAnnotationReader()
        {
            var assembly = Assembly.GetExecutingAssembly();
            string resourceName = String.Format("{0}.App_Data.{0}.XML", assembly.GetName().Name);
            this.XmlPath = resourceName;
            using (Stream stream = assembly.GetManifestResourceStream(resourceName))
            {
                using (StreamReader reader = new StreamReader(stream))
                {
                    XmlDocument doc = new XmlDocument();
                    doc.Load(reader);
                    this.Document = doc;
                }
            }
        }

        public XmlAnnotationReader(string xmlPath)
        {
            this.XmlPath = xmlPath;
            if (File.Exists(xmlPath))
            {
                XmlDocument doc = new XmlDocument();
                doc.Load(this.XmlPath);
                this.Document = doc;
            }
            else
                throw new FileNotFoundException(String.Format("Could not find the XmlDocument at the specified path: {0}\r\nCurrent Path: {1}", xmlPath, Assembly.GetExecutingAssembly().Location));
        }

        /// 
        /// Retrievethe XML comments documentation for a given resource
        /// Eg. ITN.Data.Models.Entity.TestObject.MethodName
        /// 
        /// 
        public string GetCommentsForResource(string resourcePath, XmlResourceType type)
        {
            XmlNode node = Document.SelectSingleNode(string.Format("//member[starts-with(@name, '{0}:{1}')]/summary", GetObjectTypeChar(type), resourcePath));
            if (node != null)
            {
                string xmlResult = node.InnerText;
                string trimmedResult = Regex.Replace(xmlResult, @"\s+", " ");
                return trimmedResult;
            }
            return string.Empty;
        }

        /// 
        /// Retrievethe XML comments documentation for a given resource
        /// Eg. ITN.Data.Models.Entity.TestObject.MethodName
        /// 
        /// 
        public ObjectDocumentation[] GetCommentsForResource(Type objectType)
        {
            List comments = new List();
            string resourcePath = objectType.FullName;

            PropertyInfo[] properties = objectType.GetProperties();
            FieldInfo[] fields = objectType.GetFields();
            List objectNames = new List();
            objectNames.AddRange(properties.Select(x => new ObjectDocumentation() { PropertyName = x.Name, Type = XmlResourceType.Property }).ToList());
            objectNames.AddRange(properties.Select(x => new ObjectDocumentation() { PropertyName = x.Name, Type = XmlResourceType.Field }).ToList());

            foreach (var property in objectNames)
            {
                XmlNode node = Document.SelectSingleNode(string.Format("//member[starts-with(@name, '{0}:{1}.{2}')]/summary", GetObjectTypeChar(property.Type), resourcePath, property.PropertyName));
                if (node != null)
                {
                    string xmlResult = node.InnerText;
                    string trimmedResult = Regex.Replace(xmlResult, @"\s+", " ");
                    property.Documentation = trimmedResult;
                    comments.Add(property);
                }
            }
            return comments.ToArray();
        }

        /// 
        /// Retrievethe XML comments documentation for a given resource
        /// 
        /// The type of class to retrieve documenation on
        /// The name of the property in the specified class
        /// 
        /// 
        public string GetCommentsForResource(Type objectType, string propertyName, XmlResourceType resourceType)
        {
            List comments = new List();
            string resourcePath = objectType.FullName;

            string scopedElement = resourcePath;
            if (propertyName != null && resourceType != XmlResourceType.Type)
                scopedElement += "." + propertyName;
            XmlNode node = Document.SelectSingleNode(String.Format("//member[starts-with(@name, '{0}:{1}')]/summary", GetObjectTypeChar(resourceType), scopedElement));
            if (node != null)
            {
                string xmlResult = node.InnerText;
                string trimmedResult = Regex.Replace(xmlResult, @"\s+", " ");
                return trimmedResult;
            }
            return string.Empty;
        }

        private string GetObjectTypeChar(XmlResourceType type)
        {
            switch (type)
            {
                case XmlResourceType.Field:
                    return "F";

                case XmlResourceType.Method:
                    return "M";

                case XmlResourceType.Property:
                    return "P";

                case XmlResourceType.Type:
                    return "T";
            }
            return string.Empty;
        }
    }

    public class ObjectDocumentation
    {
        public string PropertyName { get; set; }
        public string Documentation { get; set; }
        public XmlResourceType Type { get; set; }
    }

    public enum XmlResourceType
    {
        Method,
        Property,
        Field,
        Type
    }
}






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