/// <summary>
/// 判断当前的属性类型是否与已经存在的形成“闭环”。即
/// A.B.A。 当前的最后一个A，此时形成闭环
/// </summary>
/// <param name="dicts"></param>
/// <param name="current"></param>
/// <returns></returns>
private bool HasReferenceLoop(Dictionary <int, ReferenceTypeDepthExpression> dicts,
ReferenceTypeDepthExpression current)
{
ReferenceTypeDepthExpression parent = null;
if (dicts.TryGetValue(current.ParentKey, out parent) == false)
{
return(false);
}
while (parent != null)
{
if (current.PropertyInfo.PropertyType == parent.PropertyInfo.PropertyType)
{
return(true);
}
if (dicts.TryGetValue(parent.ParentKey, out parent) == false)
{
return(false);
}
}
return(false);
}
private void CreateTypeVistor()
{
ParameterExpression paraExpression = Expression.Parameter(typeof(T), "t");
Tuple <IDictionary <int, ReferenceTypeDepthExpression>, IList <ValueTypeMapping> > selected =
RecursiveGetAllSelectedProperties();
IDictionary <int, ReferenceTypeDepthExpression> referenceTypes = selected.Item1;
IList <ValueTypeMapping> valueTypes = selected.Item2;
#region 首先，根据深度对引用类型进行处理，生成相应的Expression
IOrderedEnumerable <ReferenceTypeDepthExpression> values = referenceTypes.Values.OrderBy(t => t.Depth);
foreach (ReferenceTypeDepthExpression value in values)
{
//父节点类型为根类型，即T
if (value.ParentKey == 0)
{
value.Expression = CreatePropertyAccesorExpression(value.PropertyInfo, paraExpression, null);
}
else
{
ReferenceTypeDepthExpression parent = null;
if (
referenceTypes.TryGetValue(value.ParentKey, out parent) == false)
{
LogHelper.Logger.Error("failed to get parent ReferenceTypeDepthException.");
}
value.Expression = CreatePropertyAccesorExpression(value.PropertyInfo, parent.Expression, null);
}
}
#endregion
#region 其次，处理所有的值类型或字符串类型，生成相应的访问Func等。
foreach (ValueTypeMapping valueType in valueTypes)
{
Expression parentExpression = null;
//父节点为根类型，即T：typeof(T)
if (valueType.ParentKey == 0)
{
parentExpression = paraExpression;
}
else
{
ReferenceTypeDepthExpression parent = null;
if (
referenceTypes.TryGetValue(valueType.ParentKey, out parent) == false)
{
LogHelper.Logger.Error("failed to get parent ReferenceTypeDepthException.");
}
parentExpression = parent.Expression;
}
BlockExpression curExpression = CreatePropertyAccesorExpression(valueType.CurrentPropertyInfo,
parentExpression,
valueType.DbColumnMapping.DefaultValue);
m_dbColumnMappings.Add(valueType.DbColumnMapping);
Expression <Func <T, object> > lambda =
Expression.Lambda <Func <T, Object> >(Expression.Convert(curExpression, typeof(object)),
paraExpression);
Func <T, object> func = lambda.Compile();
m_properties.Add(valueType.DbColumnMapping.DestColumnOffset, func);
}
#endregion
}
RecursiveGetAllSelectedProperties()
{
Type stringType = typeof(string);
Type type = typeof(T);
bool hasMapping = false;
#region 递归判断是否有包含DbColumnMapping的值类型或String
var pq = new Queue <Type>();
var visitReferenceType = new List <Type>();
pq.Enqueue(type);
while (pq.Count > 0)
{
Type firstType = pq.Dequeue();
PropertyInfo[] props = firstType.GetProperties();
foreach (PropertyInfo prop in props)
{
if (prop.PropertyType.IsValueType || prop.PropertyType == stringType)
{
var attrs = (DBColumnMapping[])prop.GetCustomAttributes(typeof(DBColumnMapping), true);
bool has = attrs.Any(attr => attr.DestLabel == m_destLabel);
if (has == false)
{
continue;
}
hasMapping = true;
break;
}
//reference type
if (visitReferenceType.Contains(prop.PropertyType) == false)
{
pq.Enqueue(prop.PropertyType);
}
}
visitReferenceType.Add(firstType);
}
#endregion
//所有的引用类型（不包括string）
//key: parentKey:一个利用自增来避免重复的int参数
var referenceDict = new Dictionary <int, ReferenceTypeDepthExpression>();
//所有的值类型
var valueList = new List <ValueTypeMapping>();
#region 读取所有的引用类型、值类型及String类型的属性
int rootKey = 0;
int parentKey = 0;
var depthQueue = new Queue <Tuple <int, Type, int> >();
depthQueue.Enqueue(new Tuple <int, Type, int>(parentKey++, type, 0));
while (depthQueue.Count > 0)
{
var firstNode = depthQueue.Dequeue();
int currentKey = firstNode.Item1;
Type currentType = firstNode.Item2;
int currentDepth = firstNode.Item3;
if (currentType.IsAbstract || currentType.IsInterface)
{
LogHelper.Logger.WarnFormat("getting properties for interface or abstract class type: {0}",
currentType);
}
PropertyInfo[] props = currentType.GetProperties();
foreach (PropertyInfo prop in props)
{
//值类型或引用类型
if (prop.PropertyType.IsValueType || prop.PropertyType == stringType)
{
valueList.Add(new ValueTypeMapping(prop, currentKey, currentDepth + 1));
}
else
{
var propTypeDepthException = new ReferenceTypeDepthExpression(prop, currentKey, currentDepth + 1);
if (prop.PropertyType == type || HasReferenceLoop(referenceDict, propTypeDepthException))
{
LogHelper.Logger.WarnFormat(
"there is reference loop(like A.B.C.A) for property type:{0} in declare type:{1}",
prop.PropertyType, prop.DeclaringType);
continue;
}
depthQueue.Enqueue(new Tuple <int, Type, int>(parentKey, prop.PropertyType, currentDepth + 1));
referenceDict.Add(parentKey++, propTypeDepthException);
}
}
}
#endregion
//所有被选取的值类型
IList <ValueTypeMapping> selectedValueList = SelectedValueProperties(valueList, hasMapping);
IList <ValueTypeMapping> filteredValueList = FilterValuePropertiesByDbColumn(selectedValueList);
return
(new Tuple <IDictionary <int, ReferenceTypeDepthExpression>, IList <ValueTypeMapping> >(referenceDict, filteredValueList));
}