/// <summary>
/// 构造转换动态方法（核心代码），根据assembly可处理datarow和datareader两种转换
/// </summary>
/// <typeparam name="T">返回的实体类型</typeparam>
/// <param name="assembly">待转换数据的元数据信息</param>
/// <returns>实体对象</returns>
private static DynamicMethod BuildMethod <T>(DynamicAssembleInfo assembly, MapColumn[] mapColumns = null, string methodName = "")
{
if (methodName == null)
{
methodName = "";
}
DynamicMethod method = new DynamicMethod(methodName + assembly.MethodName + typeof(T).Name, MethodAttributes.Public | MethodAttributes.Static, CallingConventions.Standard, typeof(T),
new Type[] { assembly.SourceType }, typeof(EntityContext).Module, true);
ILGenerator generator = method.GetILGenerator();
LocalBuilder result = generator.DeclareLocal(typeof(T));
generator.Emit(OpCodes.Newobj, typeof(T).GetConstructor(Type.EmptyTypes));
generator.Emit(OpCodes.Stloc, result);
foreach (var column in mapColumns)
{
PropertyInfo property = column.Property;
var endIfLabel = generator.DefineLabel();
generator.Emit(OpCodes.Ldarg_0);
//第一组，调用AssembleInfo的CanSetted方法，判断是否可以转换
generator.Emit(OpCodes.Ldstr, column.ColumnName);
generator.Emit(OpCodes.Call, assembly.CanSettedMethod);
generator.Emit(OpCodes.Brfalse, endIfLabel);
//第二组,属性设置
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldstr, column.ColumnName);
generator.Emit(OpCodes.Call, assembly.GetValueMethod);//获取数据库值
if (property.PropertyType.IsValueType || property.PropertyType == typeof(string))
{
var cur = Nullable.GetUnderlyingType(property.PropertyType);
generator.Emit(OpCodes.Call, ConvertMethods[cur == null?property.PropertyType:cur]);//调用强转方法赋值
if (cur != null)
{
generator.Emit(OpCodes.Newobj, property.PropertyType.GetConstructor(new Type[] { cur }));
}
}
//效果类似 Name=Convert.ToString(row["PName"]);
else
{
generator.Emit(OpCodes.Castclass, property.PropertyType);
}
generator.Emit(OpCodes.Call, property.GetSetMethod());//直接给属性赋值
//效果类似 Name=row["PName"];
generator.MarkLabel(endIfLabel);
}
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ret);
return(method);
}
/// <summary>
/// 构造转换动态方法（核心代码），根据assembly可处理datarow和datareader两种转换
/// </summary>
/// <typeparam name="T">返回的实体类型</typeparam>
/// <param name="assembly">待转换数据的元数据信息</param>
/// <returns>实体对象</returns>
private static DynamicMethod BuildMethod <T>(DynamicAssembleInfo assembly, MapColumn[] mapColumns = null, string methodName = "")
{
if (methodName == null)
{
methodName = "";
}
DynamicMethod method = new DynamicMethod(methodName + assembly.MethodName + typeof(T).Name, MethodAttributes.Public | MethodAttributes.Static, CallingConventions.Standard, typeof(T),
new Type[] { assembly.SourceType }, typeof(EntityContext).Module, true);
ILGenerator generator = method.GetILGenerator();
LocalBuilder result = generator.DeclareLocal(typeof(T));
generator.Emit(OpCodes.Newobj, typeof(T).GetConstructor(Type.EmptyTypes));
generator.Emit(OpCodes.Stloc, result);
foreach (var column in mapColumns)
{
PropertyInfo property = column.Property;
var endIfLabel = generator.DefineLabel();
var tmpIfLabel = generator.DefineLabel();
generator.Emit(OpCodes.Ldarg_0);
//第一组，调用AssembleInfo的CanSetted方法，判断是否可以转换
generator.Emit(OpCodes.Ldstr, column.ColumnName);
generator.Emit(OpCodes.Call, assembly.CanSettedMethod);
generator.Emit(OpCodes.Brfalse, endIfLabel);
//第二组,属性设置
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ldarg_0);
generator.Emit(OpCodes.Ldstr, column.ColumnName);
generator.Emit(OpCodes.Call, assembly.GetValueMethod);//获取数据库值
if (property.PropertyType.IsValueType || property.PropertyType == typeof(string))
{
if (property.PropertyType.IsEnum)
{
if (column.ColType == "Int32")
{
generator.Emit(OpCodes.Unbox_Any, property.PropertyType);
}
else if (column.ColType == "String")
{
generator.Emit(OpCodes.Ldtoken, property.PropertyType);
generator.Emit(OpCodes.Call, typeof(Type).GetMethod("GetTypeFromHandle", new Type[] { typeof(RuntimeTypeHandle) }));
generator.Emit(OpCodes.Call, assembly.EnumConvert);
generator.Emit(OpCodes.Unbox_Any, property.PropertyType);
}
}
else
{
LocalBuilder tmp = null;
var cur = Nullable.GetUnderlyingType(property.PropertyType);
var tmpType = cur;
if (cur == null)
{
cur = property.PropertyType;
}
if (column.ColType == "String" && cur == typeof(decimal))
{
tmp = generator.DeclareLocal(typeof(object));
var tmpBool = generator.DeclareLocal(typeof(bool));
generator.Emit(OpCodes.Call, ConvertMethods[typeof(string)]); //调用强转方法转；
generator.Emit(OpCodes.Stloc, tmp); //
generator.Emit(OpCodes.Ldloc, tmp); //
generator.Emit(OpCodes.Call, assembly.CanScientific); //调用判断；
generator.Emit(OpCodes.Stloc, tmpBool); //
generator.Emit(OpCodes.Ldloc, tmpBool); //
generator.Emit(OpCodes.Brfalse_S, tmpIfLabel); //
generator.Emit(OpCodes.Ldloc, tmp); //
generator.Emit(OpCodes.Call, ConvertMethods[typeof(double)]); //调用强转方法转；
generator.Emit(OpCodes.Box, typeof(Double));
generator.Emit(OpCodes.Stloc, tmp);
}
generator.MarkLabel(tmpIfLabel);
//
if (tmp != null)
{
generator.Emit(OpCodes.Ldloc, tmp);
}
generator.Emit(OpCodes.Call, ConvertMethods[cur]);//调用强转方法赋值
if (tmpType != null)
{
generator.Emit(OpCodes.Newobj, property.PropertyType.GetConstructor(new Type[] { tmpType }));
}
}
}
//效果类似 Name=Convert.ToString(row["PName"]);
else
{
generator.Emit(OpCodes.Castclass, property.PropertyType);
}
generator.Emit(OpCodes.Call, property.GetSetMethod());//直接给属性赋值
//效果类似 Name=row["PName"];
generator.MarkLabel(endIfLabel);
}
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ret);
return(method);
}
/// <summary>
/// 构造转换动态方法（核心代码），根据assembly可处理datarow和datareader两种转换
/// </summary>
/// <typeparam name="T">返回的实体类型</typeparam>
/// <param name="assembly">待转换数据的元数据信息</param>
/// <returns>实体对象</returns>
private static MethodInfo BuildMethod <T>(DynamicAssembleInfo assembly, MapColumn[] mapColumns = null, string methodName = "")
{
var asmName = new AssemblyName("MyClass");
//首先就需要定义一个程序集
var defAssembly = AppDomain.CurrentDomain.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.RunAndSave);
//首先就需要定义一个程序集
//var defAssembly = AppDomain.CurrentDomain.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.RunAndSave);
//if (methodName==null)
//{
// methodName = "";
//}
var defModuleBuilder = defAssembly.DefineDynamicModule("MyModule", "MyAssembly.dll");
var defClassBuilder = defModuleBuilder.DefineType("MyClass", TypeAttributes.Public);
//定义一个方法
var method = defClassBuilder.DefineMethod("MyMethod",
MethodAttributes.Public,
typeof(T),//返回类型
new Type[] { assembly.SourceType }//参数的类型
);
//DynamicMethod method = new DynamicMethod(methodName+assembly.MethodName + typeof(T).Name, MethodAttributes.Public | MethodAttributes.Static, CallingConventions.Standard, typeof(T),
// new Type[] { assembly.SourceType }, typeof(EntityContext).Module, true);
ILGenerator generator = method.GetILGenerator();
LocalBuilder result = generator.DeclareLocal(typeof(T));
generator.Emit(OpCodes.Newobj, typeof(T).GetConstructor(Type.EmptyTypes));
generator.Emit(OpCodes.Stloc, result);
foreach (var column in mapColumns)
{
PropertyInfo property = column.Property;
var endIfLabel = generator.DefineLabel();
var tmpIfLabel = generator.DefineLabel();
generator.Emit(OpCodes.Ldarg_1);
//第一组，调用AssembleInfo的CanSetted方法，判断是否可以转换
generator.Emit(OpCodes.Ldstr, column.ColumnName);
generator.Emit(OpCodes.Call, assembly.CanSettedMethod);
generator.Emit(OpCodes.Brfalse, endIfLabel);
//第二组,属性设置
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ldarg_1);
generator.Emit(OpCodes.Ldstr, column.ColumnName);
generator.Emit(OpCodes.Call, assembly.GetValueMethod);//获取数据库值
if (property.PropertyType.IsValueType || property.PropertyType == typeof(string))
{
if (property.PropertyType.IsEnum)
{
if (column.ColType == "Int32")
{
generator.Emit(OpCodes.Unbox_Any, property.PropertyType);
}
else if (column.ColType == "String")
{
generator.Emit(OpCodes.Ldtoken, property.PropertyType);
generator.Emit(OpCodes.Call, typeof(Type).GetMethod("GetTypeFromHandle", new Type[] { typeof(RuntimeTypeHandle) }));
generator.Emit(OpCodes.Call, assembly.EnumConvert);
generator.Emit(OpCodes.Unbox_Any, property.PropertyType);
}
}
else
{
LocalBuilder tmp = null;
var cur = Nullable.GetUnderlyingType(property.PropertyType);
var tmpType = cur;
if (cur == null)
{
//不是可空
cur = property.PropertyType;
}
if (cur == typeof(decimal) && column.ColType == "String")
{
tmp = generator.DeclareLocal(typeof(object));
var tmpBool = generator.DeclareLocal(typeof(bool));
generator.Emit(OpCodes.Call, ConvertMethods[typeof(string)]); //调用强转方法转；
generator.Emit(OpCodes.Stloc, tmp); //
generator.Emit(OpCodes.Ldloc, tmp); //
generator.Emit(OpCodes.Call, assembly.CanScientific); //调用强转方法转；
generator.Emit(OpCodes.Stloc, tmpBool); //
generator.Emit(OpCodes.Ldloc, tmpBool); //
generator.Emit(OpCodes.Brfalse_S, tmpIfLabel); //
generator.Emit(OpCodes.Ldloc, tmp); //
generator.Emit(OpCodes.Call, ConvertMethods[typeof(double)]); //调用强转方法转；
generator.Emit(OpCodes.Box, typeof(Double));
generator.Emit(OpCodes.Stloc, tmp);
}
generator.MarkLabel(tmpIfLabel);
//
if (tmp != null)
{
generator.Emit(OpCodes.Ldloc, tmp);
}
generator.Emit(OpCodes.Call, ConvertMethods[cur]);//调用强转方法赋值
if (tmpType != null)
{
//说明是可空
generator.Emit(OpCodes.Newobj, property.PropertyType.GetConstructor(new Type[] { tmpType }));
}
}
}
//效果类似 Name=Convert.ToString(row["PName"]);
else
{
generator.Emit(OpCodes.Castclass, property.PropertyType);
}
generator.Emit(OpCodes.Call, property.GetSetMethod()); //直接给属性赋值
//效果类似 Name=row["PName"];
generator.Emit(OpCodes.Nop);
generator.MarkLabel(endIfLabel);
}
generator.Emit(OpCodes.Ldloc, result);
generator.Emit(OpCodes.Ret);
// 创建类型
var defTYpe = defClassBuilder.CreateType();
objtar = defTYpe;
var mth = defTYpe.GetMethod("MyMethod");
defAssembly.SetEntryPoint(mth);
//保存程序集
defAssembly.Save("MyAssemblydll");
return(mth);
}
