如何将这些代码更改为c#风格

本文关键字：风格 代码 | 更新日期: 2023-09-27 18:13:56

这是我的HttpService类，它工作正常。但是看起来很奇怪，每个函数中的代码都差不多。我应该在每个函数中写try/catch，特别是TaskCanceledException，如果我不在这里捕获它，我的应用程序将终止。谁能给我举个例子，告诉我如何优化代码?

[Export(typeof(IDataSource))]
public class HttpService : IDataSource
{
    HttpClient client = new HttpClient();
    public HttpService()
    {
        client.BaseAddress = new Uri("https://localhost:3721");
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
    }
    public void Initialize(CurrentUser currentUser)
    {
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
            Convert.ToBase64String(Encoding.UTF8.GetBytes(currentUser.Name + ":" + currentUser.Password)));
    }
    public async Task<IEnumerable<User>> getUsers()
    {
        try
        {
            var response = await client.GetAsync("api/User");
            //response.EnsureSuccessStatusCode(); // Throw on error code.
            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadAsAsync<IEnumerable<User>>();
                return result;
            }
            else
            {
                return null;
            }
        }
        catch (Newtonsoft.Json.JsonException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (TaskCanceledException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return null;
    }
    public async Task<IEnumerable<permission>> getPermission()
    {
        try
        {
            var response = await client.GetAsync("api/User");
            //response.EnsureSuccessStatusCode(); // Throw on error code.
            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadAsAsync<IEnumerable<permission>>();
                return result;
            }
            else
            {
                return null;
            }
        }
        catch (Newtonsoft.Json.JsonException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (TaskCanceledException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return null;
    }
    public async Task<CurrentUser> getCurrentUserInfo(User user)
    {
        try
        {
            var response = await client.GetAsync("api/User?name=" + user.Name);
            if (response.IsSuccessStatusCode)
            {
                var result = await response.Content.ReadAsAsync<CurrentUser>();
                return result;
            }
            else
            {
                return null;
            }
        }
        catch (Newtonsoft.Json.JsonException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (HttpRequestException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        catch (TaskCanceledException ex)
        {
            Console.WriteLine(ex.ToString());
        }
        return null;
    }
}

如何将这些代码更改为c#风格

如果我没有在这里捕获它，我的应用程序将终止。

不，那根本不是真的;正是调用的代码才有机会(实际上是责任)处理错误。例如:

try {
    var permission = await getPermission();
    //...
} catch(Exception ex) {
    // log, whatever
}

将异常处理放在最合适的位置将减少async方法中不必要的代码。当前所做的是使您的async方法假装没有发生任何坏事-这不是这里的最佳实践。

免责声明:我不能编译这个，所以你可能需要修改一下。

我认为你唯一能做的就是创建一个这样的方法:

public async Task<T> getAsync(string url)
{
    try
    {
        var response = await client.GetAsync(url);
        if (response.IsSuccessStatusCode)
        {
            var result = await response.Content.ReadAsAsync<T>();
            return (T)result;
        }
        else
        {
            return null;
        }
    }
    catch (Newtonsoft.Json.JsonException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    catch (HttpRequestException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    catch (TaskCanceledException ex)
    {
        Console.WriteLine(ex.ToString());
    }
    return null;
}

然后你可以这样命名它:

public async Task<IEnumerable<User>> getUsers()
{
    return await getAsync("api/User");
}
public async Task<IEnumerable<permission>> getPermission()
{
    return await getAsync("api/User");
}
public async Task<CurrentUser> getCurrentUserInfo(User user)
{
    return await getAsync("api/User?name=" + user.Name);
}
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