How to render EditForm in C#?

[Xeevis]

I'd like to test EditContext validation when some custom component is added to EditForm, but have two issues rendering the EditForm.

Can't use Model parameter to create EditContext

var cut = this.RenderComponent<EditForm>(
    Parameter(nameof(EditForm.Model), new SampleModel())
);

cut.Instance.EditContext.ShouldNotBeNull(); // throws exception

It appears EditForm.OnParametersSet() is not called, because if I pass in EditContext directly it works

var cut = this.RenderComponent<EditForm>(
    Parameter(nameof(EditForm.EditContext), new EditContext(new SampleModel()))
);

cut.Instance.EditContext.ShouldNotBeNull(); // OK

Can't use ChildContent to include inputs or other components

var cut = this.RenderComponent<EditForm>(
    Parameter(nameof(EditForm.EditContext), new EditContext(new SampleModel())),
    ChildContent<InputText>(Parameter("class", "form-control"))
); 

This throw exception

System.InvalidOperationException : Unable to set property 'ChildContent' on object of type 'EditForm'. The error was: Unable to cast object of type 'RenderFragment' to type 'RenderFragment`1[EditContext]'.

Any ideas how to get it working? Thanks.

[egil]

Hi Xeevis,

After reading the source for EditForm I am not sure why your first example isnt working. According to the code, if you only provide a Model everything should be OK.

Can you post your entire test class so I can get the full picture, as well as the version of blazor and bunit?

[Xeevis]

Hi egil, yeah should, but doesn't in the RenderComponent<> 😓

Version info: bunit 1.0.0-beta-6 .net core 3.1 Solution: BUnitEditForm.zip

public class EditFormTest : ComponentTestFixture
{
    [Fact]
    public void RenderEditForm()
    {
        var cut = RenderComponent<EditForm>(
            Parameter(nameof(EditForm.Model), new SampleModel())
        );

        cut.Instance.EditContext.ShouldNotBeNull();
    }
}

public class SampleModel
{
    public string Username { get; set; }
}

[egil]

Just did a quick debug, and OnParameterSet is indeed called. If you look a the code for EditForm, nothing sets the EditContext property inside OnParameterSet, so everything is as expected. What is set is the private _fixedEditContext, which is set by OnParameterSet on this line. See screenshot below:

Closing since this looks like it works as expected.