c# - 在 SignalR Hub 内将部分视图呈现为字符串

我正在尝试通过 SignalR Hub 在我的一个视图中动态加载部分视图内容以更新客户端数据。为此，我必须在 SignalR Hub 中将 Partial 视图呈现为字符串并将该字符串发送到客户端。

如果您想在您的 hub 方法中将视图/部分视图呈现为 html 字符串，您可以参考此博客的示例，该示例演示了如何将部分视图呈现为字符串。

RazorPartialToStringRenderer我在我的 SignalR 应用程序中使用示例代码进行了测试，这对我来说效果很好。

private readonly IRazorPartialToStringRenderer _renderer;
public ChatHub(IRazorPartialToStringRenderer renderer)
{
    _renderer = renderer;
}
public async Task SendMessage(string user, string message)
{

    var view_result_mes = await _renderer.RenderPartialToStringAsync<string>("_SayHelloPartialView", null);

    //...

以上博客引用的代码

public interface IRazorPartialToStringRenderer
{
    Task<string> RenderPartialToStringAsync<TModel>(string partialName, TModel model);
}

public class RazorPartialToStringRenderer : IRazorPartialToStringRenderer
{
    private IRazorViewEngine _viewEngine;
    private ITempDataProvider _tempDataProvider;
    private IServiceProvider _serviceProvider;
    public RazorPartialToStringRenderer(
        IRazorViewEngine viewEngine,
        ITempDataProvider tempDataProvider,
        IServiceProvider serviceProvider)
    {
        _viewEngine = viewEngine;
        _tempDataProvider = tempDataProvider;
        _serviceProvider = serviceProvider;
    }
    public async Task<string> RenderPartialToStringAsync<TModel>(string partialName, TModel model)
    {
        var actionContext = GetActionContext();
        var partial = FindView(actionContext, partialName);
        using (var output = new StringWriter())
        {
            var viewContext = new ViewContext(
                actionContext,
                partial,
                new ViewDataDictionary<TModel>(
                    metadataProvider: new EmptyModelMetadataProvider(),
                    modelState: new ModelStateDictionary())
                {
                    Model = model
                },
                new TempDataDictionary(
                    actionContext.HttpContext,
                    _tempDataProvider),
                output,
                new HtmlHelperOptions()
            );
            await partial.RenderAsync(viewContext);
            return output.ToString();
        }
    }
    private IView FindView(ActionContext actionContext, string partialName)
    {
        var getPartialResult = _viewEngine.GetView(null, partialName, false);
        if (getPartialResult.Success)
        {
            return getPartialResult.View;
        }
        var findPartialResult = _viewEngine.FindView(actionContext, partialName, false);
        if (findPartialResult.Success)
        {
            return findPartialResult.View;
        }
        var searchedLocations = getPartialResult.SearchedLocations.Concat(findPartialResult.SearchedLocations);
        var errorMessage = string.Join(
            Environment.NewLine,
            new[] { $"Unable to find partial '{partialName}'. The following locations were searched:" }.Concat(searchedLocations)); ;
        throw new InvalidOperationException(errorMessage);
    }
    private ActionContext GetActionContext()
    {
        var httpContext = new DefaultHttpContext
        {
            RequestServices = _serviceProvider
        };
        return new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
    }
}

测试结果

c# - 在 SignalR Hub 内将部分视图呈现为字符串

问题描述

解决方案

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