我正在编写下面的代码来从Azure表中检索所有实体.但我有点坚持通过实体解析员代表.我在
MSDN上找不到太多参考.
有人可以指出,如何在下面的代码中使用EntityResover？
public class ATSHelper<T> where T : ITableEntity,new()
{
CloudStorageAccount storageAccount;
public ATSHelper(CloudStorageAccount storageAccount)
{
this.storageAccount = storageAccount;
}
public async Task<IEnumerable<T>> FetchAllEntities(string tableName)
{
List<T> allEntities = new List<T>();
CloudTable table = storageAccount.CreateCloudTableClient().GetTableReference(tableName);
TableContinuationToken contToken = new TableContinuationToken();
TableQuery query = new TableQuery();
CancellationToken cancelToken = new CancellationToken();
do
{
var qryResp = await table.ExecuteQuerySegmentedAsync<T>(query,???? EntityResolver ????,contToken,cancelToken);
contToken = qryResp.ContinuationToken;
allEntities.AddRange(qryResp.Results);
}
while (contToken != null);
return allEntities;
}
}
解决方法
Here is a nice article深入描述了表存储.它还包括EntityResolver的几个示例.
理想的是拥有一个产生所需结果的通用解析器.然后,您可以将其包含在通话中.我将在这里引用所提供文章中的一个例子：
EntityResolver<ShapeEntity> shapeResolver = (pk,rk,ts,props,etag) =>
{
ShapeEntity resolvedEntity = null;
string shapeType = props["ShapeType"].StringValue;
if (shapeType == "Rectangle") { resolvedEntity = new RectangleEntity(); }
else if (shapeType == "Ellipse") { resolvedEntity = new EllipseEntity(); }
else if (shapeType == "Line") { resolvedEntity = new LineEntity(); }
// Potentially throw here if an unknown shape is detected
resolvedEntity.PartitionKey = pk;
resolvedEntity.RowKey = rk;
resolvedEntity.Timestamp = ts;
resolvedEntity.ETag = etag;
resolvedEntity.ReadEntity(props,null);
return resolvedEntity;
};
currentSegment = await drawingTable.ExecuteQuerySegmentedAsync(drawingQuery,shapeResolver,currentSegment != null ? currentSegment.ContinuationToken : null);
阅读完整的文章,以更好地了解解析器的交易.
