/// <summary>
/// Chains post-processing to a pending data loader operation
/// </summary>
/// <typeparam name="T">The type of the data loader return value</typeparam>
/// <typeparam name="TResult">The type of the result</typeparam>
/// <param name="parent">The pending data loader operation</param>
/// <param name="chainedDelegate">The delegate to execute once the data loader finishes loading</param>
/// <returns>A pending data loader operation that can return a value once the data loader and the chained delegate finish</returns>
public static IDataLoaderResult <TResult> Then <T, TResult>(this IDataLoaderResult <T> parent, Func <T, Task <TResult> > chainedDelegate)
{
return(new SimpleDataLoader <TResult>(async(cancellationToken) =>
{
var result = await parent.GetResultAsync(cancellationToken).ConfigureAwait(false);
return await chainedDelegate(result).ConfigureAwait(false);
}));
}
public IDataLoaderResult <IEnumerable <T> > GetLoader(IResolveFieldContext context, string param)
{
Type graphRepositoryType = typeof(IGraphRepository <>).MakeGenericType(new Type[] { _dataType });
dynamic service = _httpContextAccessor.HttpContext.RequestServices.GetService(graphRepositoryType);
var first = context.GetArgument <int?>("first");
//Task<IEnumerable<T>> res = null;
var metaTable = _dbMetadata.GetTableMetadatas().FirstOrDefault(x => x.Type == context.Source.GetType());
// Console.WriteLine($"--------------------------- main type {context.Source.GetType()} PK {metaTable.NamePK} _dataType {_dataType.Name}----------------------- ");
var valueField = context.Source.GetType().GetProperty(metaTable.NamePK).GetValue(context.Source, null);
IDataLoaderResult <IEnumerable <T> > res = null;
try
{
//IEquatable
if (context.Source is IBaseModel && valueField is int @int)
{
var loader = _accessor.Context.GetOrAddCollectionBatchLoader <int, T>($"GetItemsByIds_{typeof(T).Name}",
(ids) => service.GetItemsByIds(ids, context, param));
res = loader.LoadAsync(@int);
}
else if (context.Source is IBaseModel && valueField is string @string)
{
var loader = _accessor.Context.GetOrAddCollectionBatchLoader <string, T>($"GetItemsByIds_{typeof(T).Name}",
(ids) => service.GetItemsByIds(ids, context, param, isString: true));
res = loader.LoadAsync(@string);
}
else if (context.Source is IBaseModel && valueField is Guid @guid)
{
var loader = _accessor.Context.GetOrAddCollectionBatchLoader <Guid, T>($"GetItemsByIds_{typeof(T).Name}",
(ids) => service.GetItemsByIds(ids, context, param, isString: true));
res = loader.LoadAsync(@guid);
}
else if (context.Source is IdentityUser)
{
var loader = _accessor.Context.GetOrAddCollectionBatchLoader <string, T>($"GetItemsByIds_{typeof(T).Name}",
(ids) => service.GetItemsByIds(ids, context, param, isString: true));
res = loader.LoadAsync((context.Source as IdentityUser).Id);
}
else if (context.Source is IdentityRole)
{
var loader = _accessor.Context.GetOrAddCollectionBatchLoader <string, T>($"GetItemsByIds_{typeof(T).Name}",
(ids) => service.GetItemsByIds(ids, context, param, isString: true));
res = loader.LoadAsync((context.Source as IdentityRole).Id);
}
else
{
var loader = _accessor.Context.GetOrAddCollectionBatchLoader <string, T>($"GetItemsByIds_{typeof(T).Name}",
(ids) => service.GetItemsByIds(ids, context, param, isString: true));
res = loader.LoadAsync(valueField.ToString());
}
if (first.HasValue && first.Value > 0)
{
return(res);
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
return(res);
}