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c#genericsreturngeneric-listgeneric-collections
Ashish Sojitra
Ashish Sojitra

Reputation: 25

How to return Generic List with Generic Class Object in c#?

I want to return Table List with there class object and this call also generic, I don't want to use any Non-Strong type List like ArrayList on any other. 

        public List<T> GetTables()
        {
            var tbls = new List<T>();
            tbls.Add(new Table<Table1>() { Name = "Table1"});
            tbls.Add(new Table<Table2>() { Name = "Table2"});
            tbls.Add(new Table<Table3>() { Name = "Table3"});
            return tbls;
        }

in above Method, Table1, Table2, and any type table class object... There classes has no any based class, These classes use to Set of table properties with custom format.

I want to return it.

Please help me if anyone have any idea.

thank you.

Upvotes: 0

Views: 2530

Answers (2)

CicheR
CicheR

Reputation: 409

If the only common thing of the list's components is that they are Table<> generic objects, if there isn't any interface or common base class between Table1/Table2/Table2, you can simply treat them as object:

        public List<Table<IGenerateData>> GetTables()
        {
            var tbls = new List<Table<IGenerateData>>();
            tbls.Add(new Table<Table1>() { Name = "Table1"});
            tbls.Add(new Table<Table2>() { Name = "Table2"});
            tbls.Add(new Table<Table3>() { Name = "Table3"});
            return tbls;
        }

        public interface IGenerateData
        {
            void GenerateData();
        }

        public class Table1 : IGenerateData
        {           
        }

Upvotes: 2

Konstantin Dubrovnyi
Konstantin Dubrovnyi

Reputation: 36

You can't use generic type with the List without specifying type parameter explicitly. Alternatively, you can create a base class or interface that would be a parameter for the List.

I mean:

        public static List<ITable> GetTables()
        {
            var tbls = new List<ITable>();
            tbls.Add(new Table<Table1> { Name = "Table1"});
            tbls.Add(new Table<Table2> { Name = "Table2"});
            tbls.Add(new Table<Table3> { Name = "Table3"});
            return tbls;
        }

        public class Table<T> : ITable
        {
            public T TableInstance { get; set; }
            public Type TableType => typeof(T);
            public string Name { get; set; }
        }

        public interface ITable
        {
            Type TableType { get; }
            public string Name { get; set; }
        }

Upvotes: 1

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