TableServiceExtensionMethods.AsTableServiceQuery Method

// Get contacts filtered by prefix.
public static List<ContactEntity> GetContactsByPrefix(string prefix)
{
    // Get data context.
    TableServiceContext context = tableClient.GetDataServiceContext();

    CloudTableQuery<ContactEntity> query;

    // Query entities to return names beginning with the specified letter.
    // Note that because wildcard queries are not supported, it's necessary to perform prefix  
    // matching by using string comparisons.
    if (!String.IsNullOrEmpty(prefix) && Char.IsLetter(prefix[0]))
    {
        char prefixChar = prefix[0];
        int nextCharValue = ((int)prefixChar) + 1;
        char nextChar = (char)nextCharValue;
        query = context.CreateQuery<ContactEntity>(tableName)
                .Where(e => (e.FirstName.CompareTo(prefixChar.ToString().ToUpper()) >= 0 
                    && e.FirstName.CompareTo(nextChar.ToString().ToUpper()) < 0))
                .AsTableServiceQuery<ContactEntity>();
    }
    else
    {
        query = context.CreateQuery<ContactEntity>(tableName).AsTableServiceQuery<ContactEntity>();
    }

    // Populate list of entities from query results.
    List<ContactEntity> list = new List<ContactEntity>();
    foreach (ContactEntity entity in query)
    {
        list.Add(entity);
    }

    return list;
}

// Class to represent the table schema
public class ContactEntity : TableServiceEntity
{
    public ContactEntity()
    {
    }

    public string FirstName { get; set; }
    public string LastName { get; set; }
    public string Email { get; set; }
    public string HomePhone { get; set; }
    public string CellPhone { get; set; }
    public string StreetAddress { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string ZipCode { get; set; }
}