/// <summary>
/// 异步执行查询并将第一个结果集包装成 DataTable 返回
/// </summary>
/// <param name="query">要执行的查询对象</param>
/// <param name="token">取消指示</param>
/// <returns>查询结果</returns>
public static async Task <DataTable> ExecuteDataTableAsync(this IAsyncDbExecutableQuery query, CancellationToken token = default(CancellationToken))
{
using (var context = await query.ExecuteAsync(token))
{
return(await context.LoadDataTableAsync(0, 0, token));
}
}
/// <summary>
/// 异步执行没有结果的查询
/// </summary>
/// <param name="query">要执行的查询对象</param>
/// <param name="token">取消指示</param>
/// <returns>查询所影响的行数</returns>
public static async Task <int> ExecuteNonQueryAsync(this IAsyncDbExecutableQuery query, CancellationToken token = default(CancellationToken))
{
using (var context = await query.ExecuteAsync(token))
{
return(context.RecordsAffected);
}
}
/// <summary>
/// 异步执行查询并将所有结果集包装成 DataTable 返回
/// </summary>
/// <param name="query">要执行的查询对象</param>
/// <param name="token">取消指示</param>
/// <returns>查询结果</returns>
public static async Task <DataTable[]> ExecuteAllDataTablesAsync(this IAsyncDbExecutableQuery query, CancellationToken token = default(CancellationToken))
{
List <DataTable> dataTables = new List <DataTable>();
using (var context = await query.ExecuteAsync(token))
{
do
{
dataTables.Add(context.LoadDataTable(0, 0));
} while (await context.NextResultAsync());
}
return(dataTables.ToArray());
}
/// <summary>
/// 异步执行查询并返回首行首列
/// </summary>
/// <param name="query">要执行的查询对象</param>
/// <param name="token">取消指示</param>
/// <returns>查询结果</returns>
public static async Task <object> ExecuteScalarAsync(this IAsyncDbExecutableQuery query, CancellationToken token = default(CancellationToken))
{
using (var context = await query.ExecuteAsync(token))
{
var record = await context.ReadRecordAsync();
if (record != null && record.FieldCount > 0)
{
return(record[0]);
}
else
{
return(null);
}
}
}
/// <summary>
/// 异步执行查询并返回首行
/// </summary>
/// <param name="query">要执行的查询对象</param>
/// <param name="token">取消指示</param>
/// <returns>查询结果</returns>
public static async Task <DataRow> ExecuteFirstRowAsync(this IAsyncDbExecutableQuery query, CancellationToken token = default(CancellationToken))
{
//UNDONE
using (var context = await query.ExecuteAsync(token))
{
var data = context.LoadDataTable(0, 1);
if (data.Rows.Count > 0)
{
return(data.Rows[0]);
}
else
{
return(null);
}
}
}