如何在 Blazor 中呈现定义为对象的组件？

Question

我有以下代码：

<div>
@if (Components != null && Components.Count != 0) {
   foreach (ComponentBase child in Components) {
      // Render the child component here
   }
}
</div>

如何使用 RenderFragment 渲染子对象？子对象是一个模板组件，它继承了其他类（上面有 ComponentBase）。

问题是子对象已经设置了所有参数，所以我不想使用对象数据再次设置所有 RenderFragment 参数。

我在 foreach 循环中尝试过但没有奏效的方法：

foreach (ComponentBase child in Components) {
  @child // <-- does render the class text
}

foreach (ComponentBase child in Components) {
  <ComponentBase>@child</ComponentBase> // <-- error
}

foreach (ComponentBase child in Components) {
  RenderFragment renderChild = (builder) => { builder.OpenComponent(0, child.GetType()); builder.CloseComponent(); };
@renderChild; // <-- I want to render the child object as this does nothing
}

Answer 1

这几乎是 .net6 中即将推出的 DynamicComponent 的等价物

您可以通过Type 传递类型或通过TypeString 传递类型名称

public class ComponentView : ComponentBase
{
    [Parameter]
    public Type Type { get; set; }

    [Parameter]
    public string TypeString { get; set; }

    private Dictionary<string, object> parameters;

    [Parameter]
    public Dictionary<string, string> Values { get; set; }

    protected override void OnParametersSet()
    {
        if (Values is null) {
            parameters = null;
        }
        else {
            parameters = new Dictionary<string, object>();
            foreach (var pair in Values) {
                parameters[pair.Key] = pair.Value;
            }
        }
        base.OnParametersSet();
    }



    protected override void BuildRenderTree(RenderTreeBuilder builder)
    {
        if (Type is null) {
            if (string.IsNullOrWhiteSpace(TypeString)) {
                throw new Exception("You must use either Type or the TypeString paramater");
            }
            Type = Type.GetType(TypeString);
        }

        if (Type is not null) {
            builder.OpenComponent(1, Type);

            if (parameters is not null) {
                builder.AddMultipleAttributes(2, parameters);
            }
            builder.CloseComponent();
        }
        base.BuildRenderTree(builder);
    }
}

来自repo