如何在ASP.NET Core MVC中的ViewComponent中传递4个以上的参数

Question

I have a ViewComponent and I need to pass more than 4 values to the ViewComponent, but when I try, it's giving me the error below.

Error CS0746 Invalid anonymous type member declarator. Anonymous type members must be declared with a member assignment, simple name or member access.

Code looks like this.

public async Task<IViewComponentResult> InvokeAsync(
    string A, string B, string C, string D, string E)
{

}

Calling the ViewComponent

@await Component.InvokeAsync(
    "ViewComponent2",
    new { A = Model.A, filter = "B", C = Model.C, Model.D, "2" })

I will use TagHelper to pass the data and is there any way to pass a model to the ViewComponent, I have tried but the parameter is always null.

Answer 1

The compiler error itself has nothing to do with either ViewComponents or 4 parameters: The problem is the "2" in your anonymous type, which is invalid. The anonymous type you're creating has these first four parameters:

• A = Model.A
• filter = "B"
• C = Model.C
• D = Model.D - The name D is created here on the anonymous type implicitly .

However, the next parameter is "2 ", without a name and no implicit creation of a property. If you want this last parameter to compile, you'll need to give it a name of its own, eg:

new { A = Model.A, filter = "B", C = Model.C, Model.D, E = "2" }

EDIT

I should've mentioned that you'll need the names of the anonymous type's properties to match up with those declared in your InvokeAsync function, which means you'll need to change filter to B in order for that part to work. Todd Skelton's answer offers a safer approach to handling that, however.

Answer 2

You can use classes to ensure your models are correct to avoid anonymous type errors.

public class InvokeRequest
{
    public string A { get; set; }
    public string B { get; set; }
    public string C { get; set; }
    public string D { get; set; }
    public string E { get; set; }
}

public async Task<IViewComponentResult> InvokeAsync(InvokeRequest request)
{
    //...
}

@await Component.InvokeAsync("ViewComponent2", new InvokeRequest(){ A = Model.A, B = "B", C = Model.C, D = Model.D, E = "2" })