增加几个entity framework 的函数 (记录备忘)

mac2022-06-30 30

public static class DatabaseExtensions { public static DataTable SqlQueryForDataTatable(this Database db, string sql, params SqlParameter[] parameters) {

SqlConnection conn = new System.Data.SqlClient.SqlConnection(); conn.ConnectionString = db.Connection.ConnectionString; if (conn.State != ConnectionState.Open) { conn.Open(); } SqlCommand cmd = new SqlCommand(); cmd.Connection = conn; cmd.CommandText = sql;

if (parameters.Length > 0) { foreach (var item in parameters) { cmd.Parameters.Add(item); } }

SqlDataAdapter adapter = new SqlDataAdapter(cmd); DataTable table = new DataTable(); adapter.Fill(table); return table; }

public static IEnumerable SqlQueryForDynamic(this Database db, string sql, params object[] parameters) { IDbConnection defaultConn = new System.Data.SqlClient.SqlConnection(); return SqlQueryForDynamicOtherDB(db, sql, defaultConn, parameters); }

public static IEnumerable SqlQueryForDynamicOtherDB(this Database db, string sql, IDbConnection conn, params object[] parameters) { conn.ConnectionString = db.Connection.ConnectionString; if (conn.State != ConnectionState.Open) { conn.Open(); }

IDbCommand cmd = conn.CreateCommand(); cmd.CommandText = sql;

IDataReader dataReader = cmd.ExecuteReader();

if (!dataReader.Read()) { return null; //无结果返回Null }

#region 构建动态字段

TypeBuilder builder = DatabaseExtensions.CreateTypeBuilder( "EF_DynamicModelAssembly", "DynamicModule", "DynamicType");

int fieldCount = dataReader.FieldCount; for (int i = 0; i < fieldCount; i++) { //dic.Add(i, dataReader.GetName(i));

//Type type = dataReader.GetFieldType(i);

DatabaseExtensions.CreateAutoImplementedProperty( builder, dataReader.GetName(i), dataReader.GetFieldType(i)); }

#endregion

dataReader.Close(); dataReader.Dispose(); cmd.Dispose(); conn.Close(); conn.Dispose();

Type returnType = builder.CreateType();

if (parameters != null) { return db.SqlQuery(returnType, sql, parameters); } else { return db.SqlQuery(returnType, sql); } }

public static TypeBuilder CreateTypeBuilder(string assemblyName, string moduleName, string typeName) { TypeBuilder typeBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly( new AssemblyName(assemblyName), AssemblyBuilderAccess.Run).DefineDynamicModule(moduleName).DefineType(typeName, TypeAttributes.Public); typeBuilder.DefineDefaultConstructor(MethodAttributes.Public); return typeBuilder; }

public static void CreateAutoImplementedProperty(TypeBuilder builder, string propertyName, Type propertyType) { const string PrivateFieldPrefix = "m_"; const string GetterPrefix = "get_"; const string SetterPrefix = "set_";

// Generate the field. FieldBuilder fieldBuilder = builder.DefineField( string.Concat( PrivateFieldPrefix, propertyName), propertyType, FieldAttributes.Private);

// Generate the property PropertyBuilder propertyBuilder = builder.DefineProperty( propertyName, System.Reflection.PropertyAttributes.HasDefault, propertyType, null);

// Property getter and setter attributes. MethodAttributes propertyMethodAttributes = MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig;

// Define the getter method. MethodBuilder getterMethod = builder.DefineMethod( string.Concat( GetterPrefix, propertyName), propertyMethodAttributes, propertyType, Type.EmptyTypes);

// Emit the IL code. // ldarg.0 // ldfld,_field // ret ILGenerator getterILCode = getterMethod.GetILGenerator(); getterILCode.Emit(OpCodes.Ldarg_0); getterILCode.Emit(OpCodes.Ldfld, fieldBuilder); getterILCode.Emit(OpCodes.Ret);

// Define the setter method. MethodBuilder setterMethod = builder.DefineMethod( string.Concat(SetterPrefix, propertyName), propertyMethodAttributes, null, new Type[] { propertyType });

// Emit the IL code. // ldarg.0 // ldarg.1 // stfld,_field // ret ILGenerator setterILCode = setterMethod.GetILGenerator(); setterILCode.Emit(OpCodes.Ldarg_0); setterILCode.Emit(OpCodes.Ldarg_1); setterILCode.Emit(OpCodes.Stfld, fieldBuilder); setterILCode.Emit(OpCodes.Ret);

propertyBuilder.SetGetMethod(getterMethod); propertyBuilder.SetSetMethod(setterMethod); }

}

转载于:https://www.cnblogs.com/leonsky/archive/2013/03/01/2938204.html