??? 通過配置實(shí)體與表的關(guān)系映射后，就可以實(shí)現(xiàn)對表的操作了，接下來實(shí)現(xiàn)簡單對象的新增功能。下面代碼1-1是定義的操作數(shù)據(jù)對象方法的接口：

using System; using System.Collections.Generic; using System.Text; using System.Data; using System.Data.SqlClient;System.Orm.EntityManager {public {Transaction { get; set; } <T> FindAll<T>() where T : (); ? <T> FindBySql<T>( strSql) where T : (); ? <T> FindById<T>( id) where T : (); int Save<T>(T entity);int Update<T>(T entity);int Remove<T>(T entity);int Remove<>( id) where : ();} }

??? 下面先實(shí)現(xiàn)比較簡單的查詢方法，代碼1-2：

using System; using System.Collections.Generic; using System.Text; using System.Reflection; using System.Orm.CustomAttributes; using System.Data.SqlClient; using System.Collections; using System.Data; using System.Orm.DBUtility; using System.Orm.Common;namespace System.Orm.EntityManager {public class : {//......實(shí)現(xiàn)EntityManager接口... } }

??? 下面是PropertyImpl 類中FindById方法的代碼1-3：

通過主鍵ID查詢數(shù)據(jù) public <T> FindById<T>(object id) : new() {<T> listArr = new <T>();? ? type = ().GetType();? [] properties = .GetProperties(type); tableInfo = .GetTableInfo(type, .SELECT); String strSql = .GetFindByIdSql(tableInfo); [] parms = .CreateDbParameters(1);parms[0].ParameterName = tableInfo.Id.Key;parms[0].Value = id; sdr = null;try{ sdr = .ExecuteReader(.ConnectionString, .Text, strSql, parms); while (sdr.Read()){ entity = new ();foreach ( property in properties){ name = tableInfo.PropToColumn[property.Name].ToString(); .SetPropertyValue(entity, property, sdr[name]);} listArr.Add(entity);}}catch ( ex){throw ex;}finally{if (sdr != null) sdr.Close();}return listArr; } ?

??? 1-3中第一行代碼：TableInfo tableInfo = DbEntityUtils.GetTableInfo(entity,DbOperateType.SELECT);

將實(shí)體對象和操作類型傳入DbEntityUtils.GetTableInfo方法中，下面是GetTableInfo代碼1-4:

public static GetTableInfo(object entity, dbOpType) { bool breakForeach = false; string strPrimaryKey = string.Empty; type = entity.GetType(); tableInfo = new ();tableInfo.TableName = GetTableName(type); [] properties = .GetProperties(type);foreach ( property in properties){object propvalue = null; string columnName = string.Empty; string propName = columnName = property.Name; if(dbOpType != .SELECT)propvalue = .GetPropertyValue(entity, property); object[] propertyAttrs = property.GetCustomAttributes(false);for (int i = 0; i < propertyAttrs.Length; i++) {object propertyAttr = propertyAttrs[i]; if (.IsCaseColumn(propertyAttr, dbOpType))break; string tempName = GetColumnName(propertyAttr); columnName = tempName == string.Empty ? propName : tempName; if (propertyAttr is ){if (dbOpType == .INSERT){ if (.IsNullOrEmpty(propvalue)){

????????????????????????????????????? //獲取主鍵生成方式，存入tableInfo.Strategy屬性中

????????????????????????????????????? IdAttribute idAttr = propertyAttr as IdAttribute;
????????????????????????????????????? tableInfo.Strategy = idAttr.Strategy;

? strPrimaryKey = .GetPrimaryKey(propertyAttr);if (!string.IsNullOrEmpty(strPrimaryKey))propvalue = strPrimaryKey;}} tableInfo.Id.Key = columnName;tableInfo.Id.Value = propvalue; tableInfo.PropToColumn.Put(propName, columnName); breakForeach = true} }? if (breakForeach) { breakForeach = false; continue; } tableInfo.Columns.Put(columnName, propvalue); tableInfo.PropToColumn.Put(propName, columnName);} return tableInfo; }

??? 在代碼1-3中用到了獲取實(shí)體對象中自定義屬性所配置的表名、列名代碼分別為1-5：

public static string GetTableName( classType) { string strTableName = string.Empty;string strEntityName = string.Empty;strEntityName = classType.FullName;object classAttr = classType.GetCustomAttributes(false)[0];if (classAttr is ){tableAttr = classAttr as ;strTableName = tableAttr.Name;}if (string.IsNullOrEmpty(strTableName)){throw new ("實(shí)體類:" + strEntityName + "的屬性配置[Table(name=\"tablename\")]錯誤或未配置");}return strTableName; }

??? 上面是獲取表名，下面這段代碼是獲取列名，如下代碼1-6：

public static string GetColumnName(object attribute) {string columnName = string.Empty;if (attribute is ){columnAttr = attribute as ;columnName = columnAttr.Name;}if (attribute is ){idAttr = attribute as ;columnName = idAttr.Name;}return columnName; }

1-3中第二行代碼：String strSql = DbEntityUtils.GetFindByIdSql(tableInfo);
根據(jù)已經(jīng)存入表信息的對象tableInfo來生成SQL語句，代碼1-7：

public static GetFindByIdSql( tableInfo) {sbColumns = new ();if (tableInfo.Columns.ContainsKey(tableInfo.Id.Key)) tableInfo.Columns[tableInfo.Id.Key] = tableInfo.Id.Value;elsetableInfo.Columns.Put(tableInfo.Id.Key, tableInfo.Id.Value); foreach (String key in tableInfo.Columns.Keys){sbColumns.Append(key).Append(",");}sbColumns.Remove(sbColumns.ToString().Length - 1, 1);string strSql = "SELECT {0} FROM {1} WHERE {2} = " + .DbParmChar + "{2}";strSql = string.Format(strSql, sbColumns.ToString(), tableInfo.TableName, tableInfo.Id.Key); return strSql; }

??? 下面是幾個工具類代碼，ReflectionUtils，根據(jù)反射獲取或設(shè)置對象屬性值、DynamicMethodCompiler動態(tài)方法編譯，可提高反射的性能。

ReflectionUtilsusing System; using System.Collections.Generic; using System.Text; using System.Reflection;namespace System.Orm.Common {public class {public static [] GetProperties( type){return type.GetProperties(.Public | .Instance);}public static [] GetFields( type){return type.GetFields(.Public | .Instance);}public static void SetPropertyValue(obj, property, //創(chuàng)建Set委托setter = .CreateSetHandler(obj.GetType(),property);//先獲取該私有成員的數(shù)據(jù)類型type = property.PropertyType;//通過數(shù)據(jù)類型轉(zhuǎn)換value = .ConvertForType(value, type);//將值設(shè)置到對象中setter(obj, value); } public static GetPropertyValue(obj, property){//創(chuàng)建Set委托getter = .CreateGetHandler(obj.GetType(), property);//獲取屬性值return getter(obj);}public static void SetFieldValue(obj, field, value){//創(chuàng)建Set委托setter = .CreateSetHandler(obj.GetType(), field);//先獲取該私有成員的數(shù)據(jù)類型type = field.FieldType;//通過數(shù)據(jù)類型轉(zhuǎn)換value = .ConvertForType(value, type);//將值設(shè)置到對象中setter(obj, value);}public static GetFieldValue(obj, field){//創(chuàng)建Set委托getter = .CreateGetHandler(obj.GetType(), field);//獲取字段值return getter(obj); } } }

DynamicMethodCompiler代碼：

DynamicMethodCompilerusing System; using System.Collections.Generic; using System.Text; using System.Reflection; using System.Reflection.Emit;namespace System.Orm.Common {//定義GetHandler委托public delegate object (object source);
//定義SetHandler委托public delegate void (object source, object value);
//定義InstantiateObjectHandler委托public delegate object ();public sealed class {// DynamicMethodCompilerprivate DynamicMethodCompiler() { }// 創(chuàng)建InstantiateObject委托internal static CreateInstantiateObjectHandler( type){constructorInfo = type.GetConstructor(.Public |.NonPublic | .Instance, null, new [0], null);if (constructorInfo == null){throw new (string.Format("The type {0} must declare an empty constructor (the constructor may be private, internal, protected, protected internal, or public).", type));}dynamicMethod = new ("InstantiateObject",.Static |.Public, .Standard, typeof(object),null, type, true);generator = dynamicMethod.GetILGenerator();generator.Emit(.Newobj, constructorInfo);generator.Emit(.Ret);return ()dynamicMethod.CreateDelegate(typeof());}// 創(chuàng)建Get委托internal static CreateGetHandler( type, propertyInfo){getMethodInfo = propertyInfo.GetGetMethod(true);dynamicGet = CreateGetDynamicMethod(type);getGenerator = dynamicGet.GetILGenerator();getGenerator.Emit(.Ldarg_0);getGenerator.Emit(.Call, getMethodInfo);BoxIfNeeded(getMethodInfo.ReturnType, getGenerator);getGenerator.Emit(.Ret);return ()dynamicGet.CreateDelegate(typeof());}// 創(chuàng)建Get委托internal static CreateGetHandler( type, fieldInfo){dynamicGet = CreateGetDynamicMethod(type);getGenerator = dynamicGet.GetILGenerator();getGenerator.Emit(.Ldarg_0);getGenerator.Emit(.Ldfld, fieldInfo);BoxIfNeeded(fieldInfo.FieldType, getGenerator);getGenerator.Emit(.Ret);return ()dynamicGet.CreateDelegate(typeof());}// 創(chuàng)建Set委托internal static CreateSetHandler( type, propertyInfo){setMethodInfo = propertyInfo.GetSetMethod(true);dynamicSet = CreateSetDynamicMethod(type);setGenerator = dynamicSet.GetILGenerator();setGenerator.Emit(.Ldarg_0);setGenerator.Emit(.Ldarg_1);UnboxIfNeeded(setMethodInfo.GetParameters()[0].ParameterType, setGenerator);setGenerator.Emit(.Call, setMethodInfo);setGenerator.Emit(.Ret);return ()dynamicSet.CreateDelegate(typeof());}// 創(chuàng)建Set委托internal static CreateSetHandler( type, fieldInfo){dynamicSet = CreateSetDynamicMethod(type);setGenerator = dynamicSet.GetILGenerator();setGenerator.Emit(.Ldarg_0);setGenerator.Emit(.Ldarg_1);UnboxIfNeeded(fieldInfo.FieldType, setGenerator);setGenerator.Emit(.Stfld, fieldInfo);setGenerator.Emit(.Ret);return ()dynamicSet.CreateDelegate(typeof());}// 創(chuàng)建Get動態(tài)方法private static CreateGetDynamicMethod( type){return new ("DynamicGet", typeof(object),new [] { typeof(object) }, type, true);}// 創(chuàng)建Set動態(tài)方法private static CreateSetDynamicMethod( type){return new ("DynamicSet", typeof(void),new [] { typeof(object), typeof(object) }, type, true);}// BoxIfNeededprivate static void BoxIfNeeded(type, ILGenerator generator){if (type.IsValueType){generator.Emit(.Box, type);}}// UnboxIfNeededprivate static void UnboxIfNeeded(Type type, generator){if (type.IsValueType){generator.Emit(.Unbox_Any, type);}}} }

?

TypeUtils代碼：

TypeUtilsusing System; using System.Collections.Generic; using System.Text;namespace System.Orm.Common {public class {public static object ConvertForType(object value,type){switch (type.FullName){case "System.String":value = value.ToString();break;case "System.Boolean":value = bool.Parse(value.ToString());break;case "System.Int16":case "System.Int32":case "System.Int64":value = int.Parse(value.ToString());break;case "System.Double":value = double.Parse(value.ToString());break;case "System.Decimal":value = new decimal(double.Parse(value.ToString()));break; }return value;}} }

?

??? 好了，FindById方法所需的代碼和工具類代碼都在上面，到此已經(jīng)完成。

Technorati 標(biāo)簽: ORM

轉(zhuǎn)載于:https://www.cnblogs.com/wangwei123/archive/2010/07/03/1770396.html

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