i am working on a Winui/c# app with EF core and sqlite db.
i am searching in a db with multiple tables every tables contains 9M records (9,000,000).

for this heavy search i used Task.Run and async/await. now there is an issue, when i search for a data i can see that app is working fine and result is shown.
but if i do another search i get some exception:

Exception thrown: ‘System.InvalidOperationException’ in WinRT.Runtime.dll
Exception thrown: ‘System.ArgumentOutOfRangeException’ in WinRT.Runtime.dll

i puted all codes into Dispatcher.TryEnqueue and issue fixed, however Task.Run does not have any effect and ui is blocking.

so how i can fix this? it seems that db can not work properly in Task.Run

await Task.Run(async () =>
 {
     await PerformSearchAsync(query, progress, cancellationTokenSource.Token);
 });

private Dictionary<TableType, Func<DbContext, IQueryable<object>>> tableMappings = new Dictionary<TableType, Func<DbContext, IQueryable<object>>>
{
    { TableType.T935, db => db.Set<Person935>() },
    { TableType.T936, db => db.Set<Person936>() },
    { TableType.T937, db => db.Set<Person937>() },
    { TableType.T938, db => db.Set<Person938>() },
    { TableType.T939, db => db.Set<Person939>() },
    { TableType.T93033, db => db.Set<Person93033>() }
};

public async Task PerformSearchAsync(string query, IProgress<int> progress, CancellationToken cancellationToken)
{
    var db = new IFDBDbContext();

    var tableQueries = new List<IAsyncEnumerable<object>>();
    
    var tableType = GetTableType(SearchQuery);

    if (tableMappings.TryGetValue(tableType, out var dbQuery))
    {
        var dbSet = dbQuery(db);
        tableQueries.Add(GetSearchResultsAsync(dbSet, query, cancellationToken));
    }

    // Track progress
    int totalTables = tableQueries.Count;
    int completedTables = 0;
    int completedItems = 0;

    foreach (var tableQuery in tableQueries)
    {
        await foreach (var item in tableQuery.WithCancellation(cancellationToken))
        {
            completedItems++;

            dispatcherQueue.TryEnqueue(() =>
            {
                DataList.Add(item);
                _tmpCompletedItems = completedItems;
            });
        }

        completedTables++;
        progress.Report((completedTables * 100) / totalTables);
    }

    dispatcherQueue.TryEnqueue(() =>
    {
        ShowStatus(DataList.Count);
    });
}

private async IAsyncEnumerable<object> GetSearchResultsAsync(IQueryable<object> dbSet, string query, [EnumeratorCancellation] CancellationToken cancellationToken)
{
    await foreach (var item in dbSet
        .Where(x => EF.Property<string>(x, nameof(BasePerson.Mobile)) != null && EF.Property<string>(x, nameof(BasePerson.Mobile)).Contains(query))
        .AsAsyncEnumerable()
        .WithCancellation(cancellationToken))
    {
        yield return item;
    }
}