.NET Core中的Azure表存储CreateQuery

Question

我将我现有的面向.NET Framework 4.6.2的类库移植到.NET Core 1.1。

看起来.NET Framework版本中的某些方法在.NET Core中不存在。两种这样的方法是table.CreateQuery和table.ExecuteQuery。

这是一个现有函数，它给我一个CreateQuery错误：

public T Get<T>(string partitionKey, string rowKey, string tableName) where T : ITableEntity, new()
            => getTable(tableName).CreateQuery<T>().Where(r => r.PartitionKey == partitionKey && r.RowKey == rowKey).FirstOrDefault();

如何在.NET Core中创建查询？

Answer 1

根据这个问题：Missing syncronous methods for dotnet core?，NetCore / Netstandard支持尚未包括API的Sync实现。

由于CreateQuery和ExecuteQuery都是Sync方法，因此我们无法在.NET Core中使用它，您只能使用ExecuteQuerySegmentedAsync，TableQuery，Fluent API并处理它返回的延续令牌。更多细节，您可以参考以下代码：

---

更新：

public static void Main(string[] args)
{
    var result = Get<BookTest3>("Aut_Fantasy", "Cert-0000000020", "DifferenetPartitionTest");
    Console.Write(result.PartitionKey);
    Console.Read();
}

public static T Get<T>(string partitionKey, string rowKey, string tableName) where T : ITableEntity, new()
{
    CloudTable table = ConnectToTable(tableName);
    TableQuery<T> employeeQuery = new TableQuery<T>().Where(
        TableQuery.CombineFilters(
            TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, partitionKey),
            TableOperators.And,
            TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.LessThan, rowKey))
        ).Take(1);
    var re = new T();
        TableContinuationToken continuationToken = null;
    do
    {
        Task<TableQuerySegment<T>> employees = table.ExecuteQuerySegmentedAsync(employeeQuery, continuationToken);
        TableQuerySegment<T> employeess = employees.Result;
        re= employeess.FirstOrDefault();
        continuationToken = employeess.ContinuationToken;
    } while (continuationToken != null);
    return re;
}

希望这可以给你一些提示。

---

更新代码：

public static void Main(string[] args)
{
    var tas = Get<BookTest3>("Aut_Fantasy", "Cert-0000000020", "DifferenetPartitionTest");
    var result = tas.Result;
    Console.Write(result.PartitionKey);
    Console.Read();
}

public async static Task<T> Get<T>(string partitionKey, string rowKey, string tableName) where T : ITableEntity, new()
{
    //new T();
    CloudTable table = ConnectToTable(tableName);
    TableQuery<T> employeeQuery = new TableQuery<T>().Where(
        TableQuery.CombineFilters(
            TableQuery.GenerateFilterCondition("PartitionKey", QueryComparisons.Equal, partitionKey),
            TableOperators.And,
            TableQuery.GenerateFilterCondition("RowKey", QueryComparisons.LessThan, rowKey))
        ).Take(1);
    var re = new T();
        TableContinuationToken continuationToken = null;
    do
    {
        var employees = await table.ExecuteQuerySegmentedAsync(employeeQuery, continuationToken);

        re = employees.FirstOrDefault();
        continuationToken = employees.ContinuationToken;
    } while (continuationToken != null);
    return re;
}

Answer 2

我会在这篇文章中解决这些方便的扩展方法:)

public static async System.Threading.Tasks.Task<IEnumerable<DynamicTableEntity>> ExecuteQueryAsync(this CloudTable table, TableQuery query)
{
    TableContinuationToken token = null;
    var retVal = new List<DynamicTableEntity>();
    do
    {
        var results = await table.ExecuteQuerySegmentedAsync(query, token);
        retVal.AddRange(results.Results);
        token = results.ContinuationToken;
    } while (token != null);

    return retVal;
}

public static async System.Threading.Tasks.Task<IEnumerable<T>> ExecuteQueryAsync<T>(this CloudTable table, TableQuery<T> query) where T : ITableEntity, new()
{
    TableContinuationToken token = null;
    var retVal = new List<T>();
    do
    {
        var results = await table.ExecuteQuerySegmentedAsync(query, token);
        retVal.AddRange(results.Results);
        token = results.ContinuationToken;
    } while (token != null);

    return retVal;
}

它们为您提供相同的功能，但使用ExecuteQueryASYNC作为方法名称