Question

您好我在以下方法中使用Async And Wait有问题。基本上我使用Neevia转换器转换我的文档，我想等待我的方法，直到转换完成。

你能帮忙吗？

public void AsyncAndWaitTillExecutionMethod(string fileName) {
      CallForConverter(fileName);
    }

    private async void CallForConverter(string fileName) {
        var result = await CallForConverterAsync(fileName);
    }

    private Task<string> CallForConverterAsync(string fileName) {
        string fromLocation;
        string toLocation;

        // For  data source
        string fileFullName = fileName;
        fromLocation = "abc"; 
        toLocation = "xyz";
        return Task.Factory.StartNew(() => ConvertUsingNeevia(fromLocation, toLocation));

    }
    private string ConvertUsingNeevia(string from, string to) {
        string success = "false";

        int TimeOut = 3000;
        try {
            Neevia.docConverter NVDC = new Neevia.docConverter();
            int Res = NVDC.convertFile(from, to, TimeOut);
        }
        catch (Exception ex) {
            throw new Exception("Exception ", ex);
        }
        success = "True";
        return success;

    }

它从CallForConverter（）方法给出了以下错误。此时无法启动异步操作。异步操作只能在异步处理程序或模块中启动，或者在MVC页面生命周期中的某些事件中启动......

Answer 1

只需从代码中删除所有async，await和（可怕的）StartNew：

public void AsyncAndWaitTillExecutionMethod(string fileName) {
    string fromLocation;
    string toLocation;

    // For  data source
    string fileFullName = fileName;
    fromLocation = "abc"; 
    toLocation = "xyz";
    ConvertUsingNeevia(fromLocation, toLocation);
}

Async和Await：MVC中的错误

1 个答案: