Generic class method using SQLite-Net

Question

I am trying to write a generic method to get the data from tables.

I am using sqlite-net ORM.

My methods compile well for delete:

public bool DeleteItem<T>(T NewItem)
{
    SQLiteConnection conn = new SQLiteConnection(GetConnection());
    var result = conn.Delete<T>(NewItem);

    //...
}

And

public void CreateTable<T>()
{
    SQLiteConnection conn = new SQLiteConnection(GetConnection());
    conn.CreateTable<T>();
    conn.Close();
}

But if I try to get Table data as list, I get a compile error at conn.Table:

T Must be a non-Abstract Type ....

Here is my code that does not want to compile:

public List<T> GetAllItems<T>(string SelTable)
{
    SQLiteConnection conn = new SQLiteConnection(GetConnection());
    List<T> MyItems = conn.Table<T>().ToList();
    conn.Close();
    return MyItems;
}

what is the question for comunity?

Serg Shevchenko
– Serg Shevchenko

2021-08-10 06:46:30 +00:00
Commented Aug 10, 2021 at 6:46 — Serg Shevchenko
– Serg Shevchenko, Commented Aug 10, 2021 at 6:46

Michael · Accepted Answer · 2021-08-09 18:53:24Z

3

The definition of Table in SQLiteConnection is

public TableQuery<T> Table<T>() where T : new();

So you have to add type constraints:

public bool DeleteItem<T>(T NewItem) where T : new()  // not required, but useful
{
    SQLiteConnection conn = new SQLiteConnection("xx");
    var result = conn.Delete<T>(NewItem);
    return true;
}
public void CreateTable<T>() where T : new()          // not required, but useful
{
    SQLiteConnection conn = new SQLiteConnection("xx");
    conn.CreateTable<T>();
    conn.Close();
}
public List<T> GetAllItems<T>(string SelTable) where T : new()
{
    SQLiteConnection conn = new SQLiteConnection("xx");
    List<T> MyItems = conn.Table<T>().ToList();
    conn.Close();
    return MyItems;
}

answered Aug 9, 2021 at 18:53

Michael

1,2967 silver badges5 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Generic class method using SQLite-Net

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related