protected IQueryable <T> Next <T>(IQueryable <T> query,
LambdaExpression includeExpression,
LambdaExpression thenIncludeExpression,
Type memberType) where T : class
{
if (next == null)
{
throw new NotImplementedException(
$"No valid convertion implemeted. Include: {includeExpression}, ThenInlude: {thenIncludeExpression}, member type: {memberType}");
}
return(next.ApplyInclude(query, includeExpression, thenIncludeExpression, memberType));
}
public virtual IQueryable <T> ApplyIncludeChains <T>(IQueryable <T> query, List <IncludeChain> includeChains) where T : class
{
var ret = query;
foreach (var chain in includeChains)
{
var param = chain.Include.Parameters[0];
if (param == null)
{
throw new InvalidOperationException(
$"Given lambda expression has no parameters, required one. Expression :{chain.Include.ToString()}");
}
if (param.Type != typeof(T))
{
throw new InvalidOperationException(
"Type of lambda expression parameter is diffrent from IQuerable generic type." +
$"Parameter type: {param.Type}, IQuerable type: {typeof(T).ToString()}");
}
var member = (chain.Include.Body as MemberExpression).Member;
if (member == null || member.MemberType != MemberTypes.Property)
{
throw new InvalidOperationException(
$"Given lambda expression is not property access expression. Expression :{chain.Include.ToString()}");
}
var memberType = ((PropertyInfo)member).PropertyType;
var enumMemberTypes = memberType.IsGenericType ? memberType.GetGenericArguments() : null;
if (enumMemberTypes != null)
{
if (enumMemberTypes.Count() != 1)
{
throw new InvalidOperationException(
$"Member generic type has {enumMemberTypes.Count()} gneric arguments. Should be 1");
}
}
if (chain.ThenIncludes.Count == 0)
{
return(chainStart.ApplyInclude(ret, chain.Include, null, memberType));
}
foreach (var thenInclude in chain.ThenIncludes)
{
var tParam = thenInclude.Parameters[0];
if (tParam == null)
{
throw new InvalidOperationException(
$"Given lambda expression has no parameters, required one. Expression :{thenInclude.ToString()}");
}
if (enumMemberTypes != null)
{
if (tParam.Type != enumMemberTypes[0])
{
throw new InvalidOperationException(
"Generic type of IEnumerable member of include is diffrent from ThenInclude expression parameter type." +
$" Include type: {enumMemberTypes[0]}, ThenInclude type: {tParam.Type}");
}
}
else if (tParam.Type != memberType)
{
throw new InvalidOperationException(
"Type of include expression parameter is diffrent from ThenInclude expression parameter type." +
$" Include type: {member.DeclaringType}, ThenInclude type: {tParam.Type}");
}
var tMember = (thenInclude.Body as MemberExpression).Member;
if (tMember == null)
{
throw new InvalidOperationException(
$"Given lambda expression is not member expression. Expression :{chain.Include.ToString()}");
}
return(chainStart.ApplyInclude(ret, chain.Include, thenInclude, memberType));
}
}
return(ret);
}