Working with Dictionary in c# - how to get data in an array?

Question

SQL

Friends, I do not know c# so deeply, so I have to ask for help.
I use someone else's class that I don't understand, but I need this functionality.
When fetching data, their sqlite is applied

public DataTable ExecuteQuery(string query)
    {
        if (!IsConnectionOpen)
        {
            throw new SqliteException("SQLite database is not open.");
        }
        
        IntPtr stmHandle = Prepare(query);
 
        int columnCount = sqlite3_column_count(stmHandle);
 
        var dataTable = new DataTable();
        for (int i = 0; i < columnCount; i++)
        {
            string columnName = Marshal.PtrToStringAnsi(sqlite3_column_name(stmHandle, i));
            dataTable.Columns.Add(columnName);
        }
        
        //populate datatable
        while (sqlite3_step(stmHandle) == SQLITE_ROW)
        {
            object[] row = new object[columnCount];
            for (int i = 0; i < columnCount; i++)
            {
                switch (sqlite3_column_type(stmHandle, i))
                {
                    case SQLITE_INTEGER:
                        row[i] = sqlite3_column_int(stmHandle, i);
                        break;
                
                    case SQLITE_TEXT:
                        IntPtr text = sqlite3_column_text(stmHandle, i);
                        row[i] = Marshal.PtrToStringAnsi(text);
                        break;

                    case SQLITE_FLOAT:
                        row[i] = sqlite3_column_double(stmHandle, i);
                        break;
                    
                    case SQLITE_NULL:
                        row[i] = null;
                        break;
                }
            }
        
            dataTable.AddRow(row);
        }
        
        Finalize(stmHandle);
        
        return dataTable;
    }

Here is the code for DataTable and DataRow

public class DataRow : Dictionary<string, object>
{
    public new object this[string column]
    {
        get
        {
            if (ContainsKey(column))
            {
                return base[column];
            }
            
            return null;
        }
        set
        {
            if (ContainsKey(column))
            {
                base[column] = value;
            }
            else
            {
                Add(column, value);
            }
        }
    }
}

public class DataTable
{
    public DataTable()
    {
        Columns = new List<string>();
        Rows = new List<DataRow>();
    }
    
    public List<string> Columns { get; set; }
    public List<DataRow> Rows { get; set; }
    
    public DataRow this[int row]
    {
        get
        {
            return Rows[row];
        }
    }
    
    public void AddRow(object[] values)
    {
        if (values.Length != Columns.Count)
        {
            throw new IndexOutOfRangeException("The number of values in the row must match the number of column");
        }
        
        var row = new DataRow();
        for (int i = 0; i < values.Length; i++)
        {
            row[Columns[i]] = values[i];
        }
        
        Rows.Add(row);
    }
}

How can I get all the data from the DataTable in a loop ?
If by rows, then I can do this dataTable.[0]["db_field_index"]
But how can I get all the data in the array?

Answer 1

Would use a better SQLite provider for standard ADO.NET, like https://system.data.sqlite.org
You can get an array of values ​​from Dictionary through Values. Or an array of KeyValuePair via ToArray(), ToList() or just a foreach loop.
So it looks like something like this:

for (int i = 0; i < dt.Rows.Count; i++)
{
    foreach (var value in dt.Rows[i].Values)
    {
        //Console.WriteLine(value);
    }
}

The order of values ​​in Values ​​is not guaranteed (but the same as for Keys keys), that is, it may differ from what you had in the database table.
So it probably makes more sense to do something like this:

for (int i = 0; i < dt.Rows.Count; i++)
{
    foreach (var kv in dt.Rows[i])
    {
        //Console.WriteLine("Column: " + kv.Key + ", value: " + kv.Value);
    }
}