Azure Cosmos DB Table API - LIST Generic

Question

We recently move form Doc DB to using the table api with COSMOS DB on Azure. We wanted a generic list method like:

public async Task<IEnumerable<T>> ListEntityAsync(Expression<Func<T, bool>> predicate)
    {
        // Filter against a property that's not partition key or row key
        TableQuery<T> query = new TableQuery<T>().Where(predicate);

        var results = _table.ExecuteQuery(query);

        return results.ToList();
    }

but we get invalid cast exceptions as the Where clause returns an IQueryable and the execute method needs TableQuery.

Any ideas would be appreciated! Thanks!

Answer 1

You can convert an IQueryable instance generated by the Where clause to TableQuery instance using the AsTableQuery extension method provided by the SDK, under the Queryable namespace (below)

References

• https://github.com/Azure/azure-storage-net/blob/master/Lib/Common/Table/Queryable/TableQueryableExtensions.cs#L126
• https://docs.microsoft.com/en-us/rest/api/storageservices/writing-linq-queries-against-the-table-service