private void CreateQueryableProjection()
{
try
{
foreach (var customMember in CustomMembers)
{
var memberQueryableExpression =
MappingService.GetMemberQueryableExpression(customMember.Key.Member.DeclaringType,
customMember.Value.Type);
var expression = memberQueryableExpression ?? customMember.Value;
_bindingExpressions.Add(customMember.Key.Member.Name,
Expression.Bind(customMember.Key.Member, expression));
}
foreach (var customMember in CustomFunctionMembers)
{
if (_bindingExpressions.ContainsKey(customMember.Key.Member.Name))
{
continue;
}
var memberQueryableExpression =
MappingService.GetMemberQueryableExpression(customMember.Key.Member.DeclaringType,
customMember.Value.Type);
var expression = memberQueryableExpression ?? customMember.Value;
_bindingExpressions.Add(customMember.Key.Member.Name,
Expression.Bind(customMember.Key.Member, expression));
}
foreach (var autoMember in AutoMembers)
{
if (_bindingExpressions.ContainsKey(autoMember.Value.Name))
{
continue;
}
var source = autoMember.Key as PropertyInfo;
var destination = autoMember.Value as PropertyInfo;
var memberQueryableExpression =
MappingService.GetMemberQueryableExpression(source.PropertyType,
destination.PropertyType);
var propertyOrField = Expression.PropertyOrField(SourceParameter, autoMember.Key.Name);
Expression expression;
if (memberQueryableExpression != null)
{
var lambdaExpression = memberQueryableExpression as LambdaExpression;
var projectionAccessMemberVisitor = new ProjectionAccessMemberVisitor(propertyOrField.Type, propertyOrField);
var clearanceExp = projectionAccessMemberVisitor.Visit(lambdaExpression.Body);
expression =
Expression.Condition(
Expression.Equal(propertyOrField, Expression.Constant(null, propertyOrField.Type)),
Expression.Constant(null, ((PropertyInfo)autoMember.Value).PropertyType), clearanceExp);
}
else
{
expression = propertyOrField;
}
_bindingExpressions.Add(autoMember.Value.Name,
Expression.Bind(autoMember.Value, expression));
}
QueryableExpression =
Expression.Lambda <Func <T, TN> >(
Expression.MemberInit(Expression.New(typeof(TN)), _bindingExpressions.Values), SourceParameter);
}
catch (Exception ex)
{
Debug.WriteLine(string.Format("Queryable projection is not supported for such mapping. Exception: {0}", ex));
}
}
private void ProcessProjectingMember(Expression sourceExp, PropertyInfo destProp)
{
var memberQueryableExpression =
MappingService.GetMemberQueryableExpression(sourceExp.Type,
destProp.PropertyType);
var tCol =
sourceExp.Type.GetInterfaces()
.FirstOrDefault(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(IEnumerable <>)) ??
(sourceExp.Type.IsGenericType &&
sourceExp.Type.GetInterfaces().Any(t => t == typeof(IEnumerable))
? sourceExp.Type
: null);
var tnCol = destProp.PropertyType.GetInterfaces()
.FirstOrDefault(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(IEnumerable <>)) ??
(destProp.PropertyType.IsGenericType &&
destProp.PropertyType.GetInterfaces().Any(t => t == typeof(IEnumerable))
? destProp.PropertyType
: null);
if (sourceExp.Type != typeof(string) && tCol != null && tnCol != null)
{
var sourceGenericType = sourceExp.Type.GetGenericArguments()[0];
var destGenericType = destProp.PropertyType.IsArray ? destProp.PropertyType.GetElementType() : destProp.PropertyType.GetGenericArguments()[0];
var genericMemberQueryableExpression =
MappingService.GetMemberQueryableExpression(sourceGenericType,
destGenericType);
MethodInfo selectMethod = null;
foreach (
var p in from m in typeof(Enumerable).GetMethods().Where(m => m.Name == "Select")
from p in m.GetParameters().Where(p => p.Name.Equals("selector"))
where p.ParameterType.GetGenericArguments().Count() == 2
select p)
{
selectMethod = (MethodInfo)p.Member;
}
Expression selectExpression = Expression.Call(
null,
selectMethod.MakeGenericMethod(sourceGenericType, destGenericType),
new[] { sourceExp, genericMemberQueryableExpression });
var destListAndCollTest = typeof(ICollection <>).MakeGenericType(destGenericType).IsAssignableFrom(destProp.PropertyType);
if (destListAndCollTest)
{
var toArrayMethod = typeof(Enumerable).GetMethod("ToList");
selectExpression = Expression.Call(null, toArrayMethod.MakeGenericMethod(destGenericType), selectExpression);
}
_bindingExpressions.Add(destProp.Name,
Expression.Bind(destProp, selectExpression));
}
else
{
Expression expression;
if (memberQueryableExpression != null)
{
var lambdaExpression = memberQueryableExpression as LambdaExpression;
var projectionAccessMemberVisitor = new ProjectionAccessMemberVisitor(sourceExp.Type, sourceExp);
var clearanceExp = projectionAccessMemberVisitor.Visit(lambdaExpression.Body);
expression =
Expression.Condition(
Expression.Equal(sourceExp, Expression.Constant(null, sourceExp.Type)),
Expression.Constant(null, destProp.PropertyType), clearanceExp);
}
else
{
expression = sourceExp;
}
_bindingExpressions.Add(destProp.Name,
Expression.Bind(destProp, expression));
}
}
