关于c＃：从MetadataWorkspace读取MaxLength

        string connectionString { get { return "Server=;Database=;Integrated Security=SSPI;"; } }

        [Test]
        public void Test()
        {
            using var dbcontext = new DB_Context(connectionString);
            var entity = new ResultInfoEntity();
            var maxLength = GetMaxLenth(dbcontext, nameof(ResultInfoEntity), nameof(entity.EntName));
        }

        private int GetMaxLenth(DbContext context, string entityName, string propertyName)
        {
            var tables = context.Model.GetEntityTypes();
            var table = tables.First(type => type.ClrType.Name == entityName);
            return table.FindProperty(propertyName).GetMaxLength() ?? -1;
        }

 

获取数据库字段名和MaxLength，放到字典

       static public Dictionary<string, int> GetColumeMaxLengthDictionary<T>(DbContext dbcontext, T entity)
        {
            //var entity1 = default(T);
            //var entity2 = typeof(T);

            var entityName = typeof(T).Name;

            var colume_maxLength = new Dictionary<string, int>();

            Type type = entity.GetType();
            PropertyInfo[] ps = type.GetProperties();
            foreach (PropertyInfo i in ps)
            {
                if (i.PropertyType == typeof(string) || i.PropertyType == typeof(decimal))
                {
                    if (!colume_maxLength.ContainsKey(i.Name))
                    {
                        var ml = GetMaxLenth(dbcontext, entityName, i.Name);
                        colume_maxLength.Add(i.Name, ml);
                    }
                }
            }

            return colume_maxLength;
        }

调用

            var dbcontext = new DB_Context_CIS(this.CurrentService.ConnectionString);
            var entity = new ResultInfoEntity();
            var maxLengthDictionary = this.GetColumeMaxLengthDictionary(dbcontext, entity);

            var dbcontextTarget = new DB_Context_CIS(this.CurrentService.TargetConnectionString);
            var entityTarget = new ResultInfoEntity();
            var maxLengthDictionaryTarget = this.GetColumeMaxLengthDictionary(dbcontextTarget, entityTarget);