如何將EntityFramework實體類轉換爲JSON字符串

前些天在轉換EntityFramework實體類爲JSON時出錯，我想很多朋友肯定也有相同遭遇。下面這個自定義的轉換參考了一些網上的資料，實際出處記不太清楚了，好像來自CSDN論壇，感謝這些達人們。中間遇到一些問題，自己改了一些地方，比如對DateTime?類型的處理。

 

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Collections; using System.Reflection; using System.Data.Objects.DataClasses; using Utility; namespace Utilities { public static class EntityObjectExtensionMethods { #region 實體擴展方法 /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <returns></returns> public static String ToEntitiesJson(this EntityObject obj) { return new EntitiesTools().EntitiesToJson(obj, ""); } /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <param name="Include">獲取子對象：使用，號分開</param> /// <returns></returns> public static String ToEntitiesJson(this EntityObject obj, String Include) { return new EntitiesTools().EntitiesToJson(obj, Include); } /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <returns></returns> public static String ToEntitiesJson(this IQueryable obj) { return new EntitiesTools().EntitiesToJson(obj, ""); } /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <param name="Include">獲取子對象：使用，號分開</param> /// <returns></returns> public static String ToEntitiesJson(this IQueryable obj, String Include) { return new EntitiesTools().EntitiesToJson(obj, Include); } /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <param name="Include">獲取子對象：使用，號分開</param> /// <returns></returns> public static String ToEntitiesJson(this IList obj, String Include) { return new EntitiesTools().EntitiesToJson(obj, Include); } #endregion } #region 轉換實體信息爲Json /// <summary> /// 轉換實體信息爲Json /// </summary> public class EntitiesTools { #region 轉換實體信息爲Json /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <param name="Include">獲取子對象：使用，號分開</param> /// <returns></returns> public String EntitiesToJson(Object obj, String Include) { Type type = obj.GetType(); String sJosnString = ""; StringBuilder TempStringJson = new StringBuilder(); StringBuilder json = new StringBuilder(); switch (type.Name) { case "ObjectQuery`1": TempStringJson.Clear(); json.Append("["); foreach (Object _obj in obj as IQueryable) { TempStringJson.Append(EntitiesToJson(_obj, Include, 0)); TempStringJson.Append(","); } sJosnString = TempStringJson.ToString(); json.Append(sJosnString.Substring(0, sJosnString.Length - 1)); json.Append("]"); break; case "List`1": TempStringJson.Clear(); json.Append("["); foreach (Object _obj in obj as IList) { TempStringJson.Append(EntitiesToJson(_obj, Include, 0)); TempStringJson.Append(","); } sJosnString = TempStringJson.ToString(); json.Append(sJosnString.Substring(0, sJosnString.Length - 1)); json.Append("]"); break; default: json.Append(EntitiesToJson(obj, Include, 0)); break; } return json.ToString(); } /// <summary> /// 轉換實體信息爲Json /// </summary> /// <param name="obj">實體對象</param> /// <param name="Include">獲取子對象：使用，號分開</param> /// <param name="Level">當前遞歸的層級</param> /// <returns></returns> private String EntitiesToJson(Object obj, String Include, int Level) { if (obj == null) { return null; } StringBuilder TempStringJson = new StringBuilder(); List<String> IncludeA = Include.Split(',').ToList<String>(); //需要排除的屬性類型 List<String> ignoreEntityTypes = new List<String> { "EntityReference`1", "EntityState", "EntityKey", "EntitySetName" }; //實體集合 List<String> ListType = new List<String> { "EntityCollection`1" }; //數據類型(非實體集合類型) List<String> EntitesType = new List<String> { "Binary", "Boolean", "DateTime", "DateTimeOffset", "Decimal", "Double", "Guid", "Int16", "Int32", "Int64", "Single", "String", "Time" }; //未支持的數據類型 List<String> NotType = new List<String> { "Byte", "SByte" }; StringBuilder json = new StringBuilder(); json.Append("{"); Type type = obj.GetType(); PropertyInfo[] propertyInfoList = type.GetProperties(); string doubleQuote = "/""; #region 迭代屬性 foreach (PropertyInfo _PropertyInfo in propertyInfoList) { #region 排除類型 if (ignoreEntityTypes.Contains(_PropertyInfo.PropertyType.Name)) { continue; } #endregion var propertyName = _PropertyInfo.Name; var propertyType = _PropertyInfo.PropertyType; var propertyValue = _PropertyInfo.GetValue(obj, null); try { #region 值=null if (propertyValue == null) { json.Append(doubleQuote + propertyName + doubleQuote + ":" + "null"); json.Append(","); continue; } #endregion #region 非實體集合類型 if (EntitesType.Contains(propertyValue.GetType().Name)) { try { TempStringJson.Clear(); TempStringJson.Append(doubleQuote + propertyName + doubleQuote + ":" + StringFormat(propertyValue, propertyType)); TempStringJson.Append(","); json.Append(TempStringJson); continue; } catch (Exception Err) { throw Err; } } #endregion #region 非Include對象 if (!IncludeA.Contains(propertyName)) { json.Append(doubleQuote + propertyName + doubleQuote + ":" + "null"); json.Append(","); continue; } #endregion #region 實體集合類型 if (ListType.Contains(propertyValue.GetType().Name) && Level == 0) { try { TempStringJson.Clear(); bool IsNull = true; //用來判斷集合是否爲空，待改善的方法 foreach (Object p in (IRelatedEnd)propertyValue) { IsNull = false; break; } if (IsNull) { TempStringJson.Append(doubleQuote + propertyName + doubleQuote + ":" + "null"); TempStringJson.Append(","); continue; } StringBuilder ListJosnString = new StringBuilder(); json.Append(doubleQuote + propertyName + doubleQuote + ":["); foreach (Object p in (IRelatedEnd)propertyValue) { String Child = EntitiesToJson(p, Include, 1); ListJosnString.Append(Child); ListJosnString.Append(","); } String sListJosnString = ListJosnString.ToString(); TempStringJson.Append(sListJosnString.Substring(0, sListJosnString.Length - 1)); TempStringJson.Append("]"); TempStringJson.Append(","); json.Append(TempStringJson); continue; } catch (Exception Err) { throw Err; } } #endregion #region 其他類型[應該只剩下實體對象了],有可能有沒有考慮到的情況！ try { TempStringJson.Clear(); TempStringJson.Append(doubleQuote + propertyName + doubleQuote + ":" + EntitiesToJson(propertyValue, Include, 1)); TempStringJson.Append(","); json.Append(TempStringJson); continue; } catch (Exception Err) { throw Err; } #endregion } catch (Exception Err) { json.Append(doubleQuote + propertyName + doubleQuote + ":" + "null"); json.Append(","); continue; } } #endregion String sJosnString = json.ToString(); return sJosnString.Substring(0, sJosnString.Length - 1) + "}"; } private string StringFormat(object val, Type type) { string str = val.ToString(); if (type == typeof(string)) { str = String2Json(str); str = "/"" + str + "/""; } else if (type == typeof(DateTime) || Nullable.GetUnderlyingType(type) == typeof(DateTime)) { str = DateTimeUtils.DateNetToJs((DateTime)val); //str = "/" + str + ""; } else if (type == typeof(bool)) { str = str.ToLower(); } return str; } /// <summary> /// 過濾特殊字符 /// </summary> /// <param name="s"></param> /// <returns></returns> private static string String2Json(String s) { StringBuilder sb = new StringBuilder(); for (int i = 0; i < s.Length; i++) { char c = s.ToCharArray()[i]; switch (c) { case '/"': sb.Append("///""); break; case '//': sb.Append("////"); break; case '/': sb.Append("///"); break; case '/b': sb.Append("//b"); break; case '/f': sb.Append("//f"); break; case '/n': sb.Append("//n"); break; case '/r': sb.Append("//r"); break; case '/t': sb.Append("//t"); break; default: sb.Append(c); break; } } return sb.ToString(); } #endregion } #endregion }

 

使用，例如我的User是EF一個實體類，要將User轉爲JSON，可以：

//從數據庫獲取User User u = GetSingleUser(1); string json = u.ToEntitiesJson();