DataPortal.Fetch and other DataPortal Methods

[Greg90277]

I am at a complete loss as to how to implement DataPortal methods under CSLA 7.

Here's the Fetch method signature from CSLA 7:

    public async Task<DataPortalResult> Fetch(Type objectType, object criteria, DataPortalContext context, bool isSync)

What is the required parameter:
DataPortalContext context

From where do I get it and how do I provide it?

Thanks in advance for helping me out on this - trying to upgrade to the latest and greatest!!

[TheCakeMonster]

If I understand your question correctly, I think you are mixing up the definition of the contract that the data portal implementations must fulfil with what the data access methods in your business objects must be like. The method signature you have shown appears to be to be what a data portal implementation must fulfil, which for most people is an internal implementation detail you do not need to worry about. This only matters if you build your own data portal.

If you are creating a data access method in a CSLA business object, then it should be void-returning and have one of the [Fetch], [Insert], [Update], [Delete] or [DeleteSelf] attributes applied. That's more or less the only absolute requirement from a technical perspective; you will want to pass parameters to provide context (such as an integer or Guid identify for a fetch operation) but what parameters you pass is entirely up to you.

Take a look at the BlazorExample project in the Samples folder for an example of how to build CSLA objects, for example https://github.com/MarimerLLC/csla/blob/main/Samples/BlazorExample/BlazorExample/Shared/PersonEdit.cs

[rockfordlhotka]

From the perspective of a business developer, @TheCakeMonster covers the primary change: the server-side data portal operation methods are now identified by operation attributes such as Fetch, FetchChild, Insert, etc. This is instead of having the hard-coded DataPortal_XYZ method names in earlier versions of CSLA.

  [Fetch]
  private void Fetch(int id)
  {
  }

The client-side code should no longer use any static helper methods (like DataPortal.Fetch) and instead should use an instance of the DataPortal<T> type. Usually you'll get an IDataPortal<T> injected into your page - like in Blazor:

@inject IDataPortal<PersonEdit> portal

@code
{
  private async Task ButtonClick()
  {
    var person = await portal.FetchAsync(123);
  ]
}