private void CreatBindingFromSimple(ref Tuple<Expression, Expression, bool, string> configExpression, Type typeSource, Type typeTarget, PropertyInfo propTarget)
{
// 没有特殊的操作
if (typeSource == typeTarget)
{
// 创建成员绑定
CreateMemberBinding(configExpression.Item1, propTarget, configExpression.Item3);
}
else
{
// 尝试查找mapper
var externalMapper = GetAndCheckMapper(typeSource, typeTarget, configExpression.Item4);
// 如果此时未初始化映射器
externalMapper.CreateMappingExpression(_constructorFunc);
// 默认情况下，检查对象的null
Expression mapExpression = externalMapper.GetMemberInitExpression();
Expression defaultExpression = Expression.Constant(MapperHelper.GetDefaultValue(configExpression.Item1.Type), configExpression.Item1.Type);
// 修改成员
var expSource = visitorMapper.Visit(configExpression.Item1);
var changeParamaterVisitor = new ChangParameterExpressionVisitor(expSource);
mapExpression = changeParamaterVisitor.Visit(mapExpression);
// 现在可以创建正确的参数。
Expression checkIfNull = Expression.NotEqual(expSource, defaultExpression);
// 创建条件
var checkExpression = Expression.Condition(checkIfNull, mapExpression, Expression.Constant(MapperHelper.GetDefaultValue(mapExpression.Type), mapExpression.Type), mapExpression.Type);
var bindExpression = Expression.Bind(propTarget, checkExpression);
// 找到了映射器但没有配置
if (string.IsNullOrEmpty(configExpression.Item4))
{
configExpression = Tuple.Create(configExpression.Item1, configExpression.Item2, configExpression.Item3, externalMapper.Name);
}
memberForNew.Add(bindExpression);
}
}
private void CreatBindingFromSimple(ref Tuple <Expression, Expression, bool, string> configExpression, Type typeSource, Type typeTarget, PropertyInfo propTarget)
{
// no specific action.
if (typeSource == typeTarget)
{
// We create the binding.
CreateMemberBinding(configExpression.Item1, propTarget, configExpression.Item3);
}
else
{
// Try to find a mapper.
MapperConfigurationBase externalMapper = GetAndCheckMapper(typeSource, typeTarget, configExpression.Item4);
// If the mapper is not initialized at this moment
externalMapper.CreateMappingExpression(constructorFunc);
// By default, check the nullity of the object.
Expression mapExpression = externalMapper.GetMemberInitExpression();
Expression defaultExpression = Expression.Constant(MapperHelper.GetDefaultValue(configExpression.Item1.Type), configExpression.Item1.Type);
// To change the parameter.
Expression expSource = visitorMapper.Visit(configExpression.Item1, false);
ChangParameterExpressionVisitor changeParamaterVisitor = new ChangParameterExpressionVisitor(expSource);
mapExpression = changeParamaterVisitor.Visit(mapExpression);
// Now we can create with the good parameters.
Expression checkIfNull = Expression.NotEqual(expSource, defaultExpression);
// Create condition.
var checkExpression = Expression.Condition(checkIfNull, mapExpression,
Expression.Constant(MapperHelper.GetDefaultValue(mapExpression.Type), mapExpression.Type),
mapExpression.Type);
MemberAssignment bindExpression = Expression.Bind(propTarget, checkExpression);
// We find the mapper and not configured.
if (string.IsNullOrEmpty(configExpression.Item4))
{
configExpression = Tuple.Create(configExpression.Item1, configExpression.Item2, configExpression.Item3, externalMapper.Name);
}
memberForNew.Add(bindExpression);
}
}
private void CreateBindingFromList(ref Tuple<Expression, Expression, bool, string> configExpression, Type typeSource, Type typeTarget, PropertyInfo propTarget)
{
var sourceTypeList = TypeSystem.GetElementType(typeSource);
var destTypeList = TypeSystem.GetElementType(typeTarget);
if (sourceTypeList == destTypeList)
{
if (configExpression.Item2.NodeType == ExpressionType.MemberAccess)
{
CreateMemberBinding(configExpression.Item1, propTarget, configExpression.Item3);
}
}
// 使用Enumerable类的select方法来更改类型
else
{
var externalMapper = GetAndCheckMapper(sourceTypeList, destTypeList, configExpression.Item4);
externalMapper.CreateMappingExpression(_constructorFunc);
MemberAssignment expBind;
var expSource = configExpression.Item1;
var visitor = new ChangParameterExpressionVisitor(paramClassSource);
expSource = visitor.Visit(expSource);
// 为了与EF / LINQ2SQL兼容。
var expMappeur = externalMapper.GetGenericLambdaExpression();
// 创建对Select方法的调用，在Enumerable的Select中插入一个lambda表达式（参数是一个委托），通常情况下，这是不可能的，但（个人认为）编译器就像这样创建并且LINQ2SQL / EF是可以进行sql查询的
Expression select = Expression.Call(_selectMethod.MakeGenericMethod(sourceTypeList, destTypeList), new[]
{
expSource,
expMappeur
});
// 创建对ToList方法的调用
Expression toList = Expression.Call(_toListMethod.MakeGenericMethod(destTypeList), select);
if (configExpression.Item3) // 如果要检查无效（使用EF / LinqTosql，则不需要）。
{
// 测试source的属性是否为null。
Expression checkIfNull = Expression.NotEqual(expSource, Expression.Constant(MapperHelper.GetDefaultValue(expSource.Type), expSource.Type));
// 有时候ToList方法不起作用，则使用实现ToList不起作用的类
Expression asExp = Expression.TypeAs(toList, propTarget.PropertyType);
// 创建条件表达式
Expression expCondition = Expression.Condition(checkIfNull, asExp, Expression.Constant(MapperHelper.GetDefaultValue(typeTarget), typeTarget));
// 分配给目标属性。
expBind = Expression.Bind(propTarget, expCondition);
}
else
{
// 分配给目标属性。
expBind = Expression.Bind(propTarget, toList);
}
// 查找mapper
if (string.IsNullOrEmpty(configExpression.Item4))
{
configExpression = Tuple.Create(configExpression.Item1, configExpression.Item2, configExpression.Item3, externalMapper.Name);
}
memberForNew.Add(expBind);
}
}
/// <summary>
/// 为现有目标对象创建成员
/// </summary>
public virtual void CreateMemberAssignementForExistingTarget()
{
if (PropertiesMapping.Count <= 0)
{
return;
}
// 用于更改原始表达式的参数。
var paramTarget = Expression.Parameter(TargetType, paramClassSource.Name.Replace("s", "t"));
var finalAssign = new List<Expression>();
foreach (var item in PropertiesMapping)
{
var propToAssign = new ChangParameterExpressionVisitor(paramTarget).Visit(item.Item2);
var assignExpression = new ChangParameterExpressionVisitor(paramClassSource).Visit(item.Item1);
var sourceType = TypeSystem.GetElementType(item.Item2.Type);
var targetType = TypeSystem.GetElementType(item.Item1.Type);
if (string.IsNullOrEmpty(item.Item4))
{
object defaultValue = MapperHelper.GetDefaultValue(item.Item2.Type);
Expression defaultExpression = Expression.Constant(defaultValue, item.Item2.Type);
Expression checkIfNull = Expression.NotEqual(assignExpression, defaultExpression);
if (item.Item3)
{
Expression setIf = Expression.IfThen(checkIfNull, Expression.Assign(propToAssign, assignExpression));
finalAssign.Add(setIf);
}
else
{
if (!IsListOf(propToAssign.Type))
{
finalAssign.Add(Expression.Assign(propToAssign, assignExpression));
}
else
{
if (sourceType == targetType)
{
Expression toListExp = Expression.Call(_toListMethod.MakeGenericMethod(sourceType), assignExpression);
Expression setIf = Expression.IfThen(checkIfNull, Expression.Assign(propToAssign, assignExpression));
finalAssign.Add(setIf);
finalAssign.Add(toListExp);
}
}
}
}
else // 来自其他映射器。
{
var mapper = GetMapper(sourceType, targetType, false, item.Item4);
if (mapper == null)
{
continue;
}
mapper.Initialize(_constructorFunc);
Expression defaultExpression = Expression.Constant(MapperHelper.GetDefaultValue(item.Item2.Type), item.Item2.Type);
if (!IsListOf(propToAssign.Type))
{
ChangParameterExpressionVisitor changeVisitor = new ChangParameterExpressionVisitor(propToAssign, assignExpression);
Expression modifiedExpression = changeVisitor.Visit(mapper.expressionForExisting.Body);
Expression checkIfNull = Expression.NotEqual(propToAssign, defaultExpression);
Expression setIf = Expression.IfThen(checkIfNull, modifiedExpression);
assignExpression = setIf;
}
else
{
Expression checkIfNull = Expression.NotEqual(propToAssign, defaultExpression);
Expression setIf = Expression.IfThen(checkIfNull, Expression.Assign(propToAssign, assignExpression));
assignExpression = setIf;
}
finalAssign.Add(assignExpression);
}
}
if (finalAssign.Count > 0 && _delegateCallForExisting == null)
{
expressionForExisting = Expression.Lambda(Expression.Block(typeof(void), finalAssign), paramClassSource, paramTarget);
// 编译
_delegateCallForExisting = expressionForExisting.Compile();
}
}
/// <summary>
/// 将表达式分布在此类中更专一的访问方法之一。
/// </summary>
/// <param name="node">访问表达式树</param>
/// <param name="checkIfNullity">检查null值</param>
/// <returns>
/// 改变表达式，如果它或它的任何子表达式被修改; 否则，返回原始表达式。
/// </returns>
public Expression Visit(Expression node, bool checkIfNullity = false)
{
_checkNull = checkIfNullity;
if (node == null)
{
return(node);
}
if (_checkNull)
{
Expression result;
switch (node.NodeType)
{
case ExpressionType.MemberAccess:
result = VisitMember(node as MemberExpression);
break;
case ExpressionType.Parameter:
result = VisitParameter(node as ParameterExpression);
break;
case ExpressionType.Convert:
result = VisitMember((node as UnaryExpression).Operand as MemberExpression);
break;
case ExpressionType.Lambda:
LambdaExpression lambda = ((LambdaExpression)node);
// 子表达式树
if (lambda.Body.NodeType != ExpressionType.Lambda)
{
result = Visit(lambda.Body);
}
else
{
return(lambda);
}
break;
default:
result = base.Visit(node);
break;
}
bool isFirst = true;
Expression previousExpression = null;
if (_membersToCheck.Count > 1)
{
// 在分配值之前测试所有子对象。例如：source.SubClass.SubClass2.MyProperty。
foreach (MemberExpression item in _membersToCheck)
{
if (!isFirst) // 不要测试该属性的值。
{
object defaultValue = MapperHelper.GetDefaultValue(item.Type);
// 创建默认值的验证。
Expression notDefaultValue = Expression.NotEqual(item, Expression.Constant(defaultValue, item.Type));
Expression conditional = null;
// 它创建了包含上述条件的条件。
if (previousExpression != null)
{
object defaultPreviousValue = MapperHelper.GetDefaultValue(previousExpression.Type);
conditional = Expression.Condition(notDefaultValue, previousExpression, Expression.Constant(defaultPreviousValue, previousExpression.Type));
}
// 它会影响新创建的条件，这些条件将成为之前的条件。
previousExpression = conditional;
}
else // 属性
{
previousExpression = item;
isFirst = false;
}
}
return(previousExpression);
}
// 不需要递归的元素。
if (_membersToCheck.Count == 1)
{
var item = _membersToCheck.Peek();
object defaultValue = MapperHelper.GetDefaultValue(item.Type);
// 创建默认值的验证。
Expression notDefaultValue = Expression.NotEqual(item, Expression.Constant(defaultValue, item.Type));
Expression conditional = Expression.Condition(notDefaultValue, item, Expression.Constant(defaultValue, item.Type));
return(conditional);
}
return(result);
}
// 默认返回（更改参数），删除lambda表达式的验证。
if (node.NodeType == ExpressionType.Lambda)
{
LambdaExpression lambda = (LambdaExpression)node;
// 子表达式树
if (lambda.Body.NodeType != ExpressionType.Call)
{
return(base.Visit(lambda.Body));
}
return(lambda);
}
return(base.Visit(node));
}
private void CreateBindingFromList(ref Tuple <Expression, Expression, bool, string> configExpression, Type typeSource, Type typeTarget, PropertyInfo propTarget)
{
Type sourceTypeList = TypeSystem.GetElementType(typeSource);
Type destTypeList = TypeSystem.GetElementType(typeTarget);
//No change it's easy
if (sourceTypeList == destTypeList)
{
if (configExpression.Item2.NodeType == ExpressionType.MemberAccess)
{
CreateMemberBinding(configExpression.Item1, propTarget, configExpression.Item3);
}
}
// Using "Select" of Enumerable class to change type.
else
{
var externalMapper = GetAndCheckMapper(sourceTypeList, destTypeList, configExpression.Item4);
externalMapper.CreateMappingExpression(constructorFunc);
MemberAssignment expBind = null;
Expression expSource = configExpression.Item1;
ChangParameterExpressionVisitor visitor = new ChangParameterExpressionVisitor(paramClassSource);
expSource = visitor.Visit(expSource);
//For compatibility with EF/LINQ2SQL.
LambdaExpression expMappeur = externalMapper.GetGenericLambdaExpression();
// We create the call to the Select method.
// We insert a lambda expression in select of Enumerable(the parameter is a delegate),
// normally, that's impossible but (we think) that the compiler creating like this and that LINQ2SQL/EF can make the sql query.
Expression select = Expression.Call(selectMethod.MakeGenericMethod(sourceTypeList, destTypeList),
new Expression[] { expSource, expMappeur });
// We create the call to ToList method
Expression toList = Expression.Call(toListMethod.MakeGenericMethod(destTypeList), select);
if (configExpression.Item3) // If you want check the nullity(with EF/LinqTosql, you don't need).
{
// Test if the source property is null.
Expression checkIfNull = Expression.NotEqual(expSource, Expression.Constant(MapperHelper.GetDefaultValue(expSource.Type), expSource.Type));
Expression expCondition = null;
// For boxing some time the ToList method not working.
// With a class that implement a list that does not work.
Expression asExp = Expression.TypeAs(toList, propTarget.PropertyType);
// Create condition
expCondition = Expression.Condition(checkIfNull, asExp, Expression.Constant(MapperHelper.GetDefaultValue(typeTarget), typeTarget));
// Assigning to the destination propery.
expBind = Expression.Bind(propTarget, expCondition);
}
else
{
// Assigning to the destination propery.
expBind = Expression.Bind(propTarget, toList);
}
//We find the mapper
if (string.IsNullOrEmpty(configExpression.Item4))
{
configExpression = Tuple.Create(configExpression.Item1, configExpression.Item2, configExpression.Item3, externalMapper.Name);
}
memberForNew.Add(expBind);
}
}
internal virtual void CreateMemberAssignementForExistingTarget()
{
if (propertiesMapping.Count > 0)
{
// For change the parameter of the original expression.
var paramTarget = Expression.Parameter(TargetType, paramClassSource.Name.Replace("s", "t"));
ChangParameterExpressionVisitor visitSource = new ChangParameterExpressionVisitor(paramClassSource);
ChangParameterExpressionVisitor visitTarget = new ChangParameterExpressionVisitor(paramTarget);
List <Expression> finalAssign = new List <Expression>();
for (int i = 0; i < propertiesMapping.Count; i++)
{
var item = propertiesMapping[i];
var propToAssign = visitTarget.Visit(item.Item2);
Expression assignExpression = null;
assignExpression = visitSource.Visit(item.Item1);
Type sourceType = TypeSystem.GetElementType(item.Item2.Type);
Type targetType = TypeSystem.GetElementType(item.Item1.Type);
if (string.IsNullOrEmpty(item.Item4))
{
object defaultValue = MapperHelper.GetDefaultValue(item.Item2.Type);
Expression defaultExpression = Expression.Constant(defaultValue, item.Item2.Type);
Expression checkIfNull = Expression.NotEqual(assignExpression, defaultExpression);
if (item.Item3)
{
//Create check if null
Expression setIf = Expression.IfThen(checkIfNull, Expression.Assign(propToAssign, assignExpression));
finalAssign.Add(setIf);
}
else
{
if (!IsListOf(propToAssign.Type))
{
finalAssign.Add(Expression.Assign(propToAssign, assignExpression));
}
else
{
//NOT TESTED !!!!!
if (sourceType == targetType)
{
Expression toListExp = Expression.Call(toListMethod.MakeGenericMethod(sourceType), assignExpression);
Expression setIf = Expression.IfThen(checkIfNull, Expression.Assign(propToAssign, assignExpression));
finalAssign.Add(setIf);
}
}
}
}
else // Come from a other mapper.
{
var mapper = GetMapper(sourceType, targetType, false, item.Item4);
if (mapper != null)
{
mapper.Initialize(constructorFunc);
Expression defaultExpression = Expression.Constant(MapperHelper.GetDefaultValue(item.Item2.Type), item.Item2.Type);
if (!IsListOf(propToAssign.Type))
{
ChangParameterExpressionVisitor changeVisitor = new ChangParameterExpressionVisitor(propToAssign, assignExpression);
Expression modifiedExpression = changeVisitor.Visit(mapper.expressionForExisting.Body);
Expression checkIfNull = Expression.NotEqual(propToAssign, defaultExpression);
Expression setIf = Expression.IfThen(checkIfNull, modifiedExpression);
assignExpression = setIf;
}
else
{
// Use Select of Enumerable NOT TESTED !!!!!
Expression selectExp = Expression.Call(selectMethod.MakeGenericMethod(sourceType), Expression.Constant(mapper.GetDelegate()));
Expression checkIfNull = Expression.NotEqual(propToAssign, defaultExpression);
Expression setIf = Expression.IfThen(checkIfNull, Expression.Assign(propToAssign, assignExpression));
assignExpression = setIf;
}
finalAssign.Add(assignExpression);
}
}
}
if (finalAssign.Count > 0 && delegateCallForExisting == null)
{
expressionForExisting = Expression.Lambda(Expression.Block(typeof(void), finalAssign), paramClassSource, paramTarget);
// Assign the delegate.
delegateCallForExisting = expressionForExisting.Compile();
}
}
}
/// <summary>
/// Distributes the expression one of the more specialized visit methods in this class.
/// </summary>
/// <param name="node">Expression to visit.</param>
/// <param name="checkIfNullity">Check</param>
/// <returns>
/// Altered expression, if it or any subexpression was modified; otherwise, returns the original expression.
/// </returns>
public Expression Visit(Expression node, bool checkIfNullity = false)
{
checkNull = checkIfNullity;
Expression result;
if (node == null)
{
return(node);
}
if (checkNull)
{
// Treated our case
switch (node.NodeType)
{
case ExpressionType.MemberAccess:
result = VisitMember(node as MemberExpression);
break;
case ExpressionType.Parameter:
result = VisitParameter(node as ParameterExpression);
break;
case ExpressionType.Convert:
result = VisitMember((node as UnaryExpression).Operand as MemberExpression);
break;
case ExpressionType.Lambda:
LambdaExpression lambda = ((LambdaExpression)node);
//Sub expression
if (lambda.Body.NodeType != ExpressionType.Lambda)
{
result = Visit(lambda.Body);
}
else
{
return(lambda);
}
break;
default:
result = base.Visit(node);
break;
}
bool isFirst = true;
Expression previousExpression = null;
if (membersToCheck.Count > 1)
{
// We want to test all the sub objects before assigning the value.
// Ex: source.SubClass.SubClass2.MyProperty.
// Which will give :
// source.SubClass != null ? source.SubClass.SubClass2 != null ? source.SubClass.SubClass2.MyProperty :DefaultValueOfProperty :DefaultValueOfProperty.
foreach (MemberExpression item in membersToCheck)
{
if (!isFirst) // Not to test the value of the property back.
{
object defaultValue = MapperHelper.GetDefaultValue(item.Type);
// Creating verification of default value.
Expression notDefaultValue = Expression.NotEqual(item, Expression.Constant(defaultValue, item.Type));
Expression conditional = null;
// It creates a condition that includes the above condition.
if (previousExpression != null)
{
object defaultPreviousValue = MapperHelper.GetDefaultValue(previousExpression.Type);
conditional = Expression.Condition(notDefaultValue, previousExpression, Expression.Constant(defaultPreviousValue, previousExpression.Type));
}
// It affects the newly created conditions that will become the previous.
previousExpression = conditional;
}
else // here the requested property.
{
previousExpression = item;
isFirst = false;
}
}
return(previousExpression);
}
// For one element don't need recusrive.
else if (membersToCheck.Count == 1)
{
var item = membersToCheck.Peek();
object defaultValue = MapperHelper.GetDefaultValue(item.Type);
// Creating verification of default value.
Expression notDefaultValue = Expression.NotEqual(item, Expression.Constant(defaultValue, item.Type));
Expression conditional;
conditional = Expression.Condition(notDefaultValue, item, Expression.Constant(defaultValue, item.Type));
return(conditional);
}
return(result);
}
else
{
// Return by default (with change of the parameter).
// To remove validation of the lambda expression.
if ((node.NodeType == ExpressionType.Lambda))
{
LambdaExpression lambda = ((LambdaExpression)node);
// Sub expression.
if (lambda.Body.NodeType != ExpressionType.Call)
{
return(base.Visit(lambda.Body));
}
else
{
return(lambda);
}
}
else
{
return(base.Visit(node));
}
}
}