How to Convert Anonymous Type to List <dynamic> using Linq to SQL in C#

Question

I'm new to C# and Linq.

Actually, I want to return anonymous types into list. anonymous types is contain of List, String, and DateTime. I tried with the code as below but its giving an error. please help and tell me what I am missing or suggest how can I achieve this.

//Error:

System.InvalidCastException: Specified cast is not valid..

//Edited C# Linq Code

        public List<AuditInfo> GetScanAudit(object Id, DateTime? fromTime, DateTime? toTime, string type = null,
            string user = null, Pager pager = null)
        {
            using (var ctx = new PlantDataContext())
            {
                var query = from audit in ctx.AuditLog
                            join ent in ctx.Scans on audit.RecordId equals ent.Id.ToString() into audits
                            from entaudits in audits.DefaultIfEmpty()
                            where audit.TypeFullName == "ABCD.DB.Model.Scan"
                            select new
                            {
                                audit,
                                entaudits
                            };

                if (Id != null)
                {
                    query = query.Where(x => x.audit.RecordId == Id.ToString());
                }
                if (fromTime.HasValue)
                {
                    var tmp = new DateTimeOffset(fromTime.Value.ToUniversalTime());
                    query = query.Where(x => x.audit.EventDateUTC >= tmp);
                }
                if (toTime.HasValue)
                {
                    var tmp = new DateTimeOffset(toTime.Value.ToUniversalTime());
                    query = query.Where(x => x.audit.EventDateUTC <= tmp);
                }
                if (!string.IsNullOrEmpty(type))
                {
                    var parseEvent = (EventType)Enum.Parse(typeof(EventType), type);
                    query = query.Where(x => x.audit.EventType == parseEvent);
                }
                if (!string.IsNullOrEmpty(user))
                {
                    query = query.Where(x => x.audit.UserName == user);
                }
                if (pager != null)
                {
                    var totalRecords = query.Count();
                    pager.TotalRecords = totalRecords;
                    var data = query.Select(x =>
                        new AuditInfo
                        {
                            x.audit.TypeFullName, //Here Error Occurs
                            x.audit.UserName,//Here Error Occurs
                            x.audit.EventType,//Here Error Occurs
                            x.audit.EventDateUTC,//Here Error Occurs
                            @LogDetails = x.audit.LogDetails.ToList(), //Here Error Occurs
                            x.entaudits.Name,
                            @Description = x.entaudits.Description
                        })
                        .OrderByDescending(x => x.EventDateUTC)
                        .Skip(pager.From)
                        .Take(pager.PageSize);
                    try
                    {
                        var list1 = data.ToList<AuditInfo>();
                    }
                    catch (Exception e)
                    {
                    }
                    var list = data.ToList<AuditInfo>();
                    pager.RecordCount = list.Count;
                    return list;
                }
                else
                {
                    var list = query.Select(x =>
                        new AuditInfo
                        {
                            x.audit.TypeFullName,
                            x.audit.UserName,
                            x.audit.EventType,
                            x.audit.EventDateUTC,
                            @LogDetails = x.audit.LogDetails.ToList(),
                            x.entaudits.Name,
                            @Description = x.entaudits.Description
                        })
                            .OrderByDescending(x => x.EventDateUTC)
                        .ToList<AuditInfo>();
                    return list;
                }
            }
        }

When I debug the code totalRecords variable showing count 6, but is showing exception with message Specified cast is not valid at this line var list1 = data.ToList();

@CaiusJard, seems like OP wants us to convert from Linq to SQL. — jarlh
– jarlh, Commented Oct 30, 2018 at 9:20
Change your method's return type to something else: a strongly type class, or C#7 value tuples. — Salah Akbari
– Salah Akbari, Commented Oct 30, 2018 at 9:21
where do you want to use this method => GetScanAudit and why you choose return type List<dynamic> and why not List<SomeClass>? — er-sho
– er-sho, Commented Oct 30, 2018 at 9:28
What is the point to return dynamic? C# is a strongly typed programming language and there is no need for your case to return List of dynamic. If you are new to C# you should know that strong types are good, while you should avoid dynamic. — Access Denied
– Access Denied, Commented Oct 30, 2018 at 9:37

Alessandro D'Andria · Accepted Answer · 2018-10-30 10:28:07Z

9

You have to cast the anonymous objects to dynamic.

To do this with linq you can use Cast<dynamic> linq method:

var list = query.Select(x =>
    new
    {
        x.audit.TypeFullName,
        x.audit.UserName,
        x.audit.EventType,
        x.audit.EventDateUTC,
        @LogDetails = x.audit.LogDetails.ToList(),
        x.entaudits.Name,
        @Description = x.entaudits.Description
    })
    .OrderByDescending(x => x.EventDateUTC)
    .AsEnumerable()
    .Cast<dynamic>()
    .ToList<dynamic>(); \\ here exception occures
return list;

edited Oct 30, 2018 at 10:28

answered Oct 30, 2018 at 9:41

Alessandro D'Andria

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4 Comments

Sandy N Over a year ago

Not working sir. An exception of type 'System.NotSupportedException' occurred in EntityFramework.SqlServer.dll but was not handled in user code Additional information: Unable to cast the type 'Anonymous type' to type 'System.Object'. LINQ to Entities only supports casting EDM primitive or enumeration types. occurred

Alessandro D'Andria Over a year ago

@SandyN you can use .AsEnumerable() instead of .Cast<dynamic>.

Sandy N Over a year ago

still not working sir,

An exception of type 'System.InvalidCastException' occurred in System.Data.dll but was not handled in user code Additional information: Specified cast is not valid. occurred

jaycer Over a year ago

Using AsEnumerable() and Cast<dynamic>() works for me

er-sho · Accepted Answer · 2018-10-30 12:39:06Z

4

You can use strongly return type for your method like List<ClassName> instead of List<dynamic>

public List<ClassName> GetScanAudit(object Id, DateTime? fromTime, DateTime? toTime, string type = null, string user = null, Pager pager = null)
{
   ...
}

Then your query will be

var data = query.Select(x =>
                new ClassName
                {
                    TypeFullName = x.audit.TypeFullName,
                    UserName = x.audit.UserName,
                    EventType = x.audit.EventType,
                    EventDateUTC = x.audit.EventDateUTC,
                    LogDetails = x.audit.LogDetails.ToList(),
                    Name = x.entaudits.Name,
                    Description = x.entaudits.Description
                })
                .OrderByDescending(x => x.EventDateUTC)
                .Skip(pager.From)
                .Take(pager.PageSize);

var list = data.ToList<ClassName>();

And your strongly type class look like

public class ClassName
{
    public string TypeFullName { get; set; }
    public string UserName { get; set; }
    public string EventType { get; set; }
    public DateTime EventDateUTC { get; set; }
    public List<LogDetail> LogDetails { get; set; }
    public string Name { get; set; }
    public string Description { get; set; }
}

Make sure the datatype of each property should match in your .Select clause in query

Edit:

if (pager != null)
            {
                var totalRecords = query.Count();
                pager.TotalRecords = totalRecords;
                var data = query.Select(x =>
                    new AuditInfo
                    {
                        TypeFullName = x.audit.TypeFullName,
                        UserName = x.audit.UserName,
                        EventType = x.audit.EventType,
                        EventDateUTC = x.audit.EventDateUTC,
                        LogDetails = x.audit.LogDetails.ToList(),
                        Name = x.entaudits.Name,
                        Description = x.entaudits.Description
                    })
                    .OrderByDescending(x => x.EventDateUTC)
                    .Skip(pager.From)
                    .Take(pager.PageSize);
                try
                {
                    var list1 = data.ToList<AuditInfo>();
                }
                catch (Exception e)
                {
                }
                var list = data.ToList<AuditInfo>();
                pager.RecordCount = list.Count;
                return list;
            }
            else
            {
                var list = query.Select(x =>
                    new AuditInfo
                    {
                        TypeFullName = x.audit.TypeFullName,
                        UserName = x.audit.UserName,
                        EventType = x.audit.EventType,
                        EventDateUTC = x.audit.EventDateUTC,
                        LogDetails = x.audit.LogDetails.ToList(),
                        Name = x.entaudits.Name,
                        Description = x.entaudits.Description
                    })
                        .OrderByDescending(x => x.EventDateUTC)
                    .ToList<AuditInfo>();
                return list;
            }

edited Oct 30, 2018 at 12:39

answered Oct 30, 2018 at 10:01

er-sho

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18 Comments

Sandy N Over a year ago

Thank you sir I will try this one.

er-sho Over a year ago

@SandyN, let me know if it help or not?

Sandy N Over a year ago

Sure sir. I will do.

er-sho Over a year ago

make sure that => if you x.audit.TypeFullName is string then in class TypeFullName will be string and if x.audit.EventDateUTC is DateTime then in class EventDateUTC is DateTime means you must assign proper datatype to class property that should match in your select clause query

Sandy N Over a year ago

Yes sir I created another Class file for that

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