Question

我在代码的以下行中收到此错误消息：

public async Task<bool> TestMakePurchase(string productId, string payload)

错误CS0161：“ Game1.TestMakePurchase（字符串，字符串）”：并非所有代码路径返回值（CS0161）

此错误消息是什么意思，我的代码有什么问题？

完整代码：

 async void CheckPurchase()
    {

        bool purchaseIsSuccessful = await TestMakePurchase("com.website.appName.purchaseName", "");          

        if (purchaseIsSuccessful)
        {               

        }
        else
        {

        }
    }


    public async Task<bool> TestMakePurchase(string productId, string payload)
    {
        var billing = CrossInAppBilling.Current;
        try
        {
            var connected = await billing.ConnectAsync();
            if (!connected)
            {                 
                return false;
            }


            var purchase = await billing.PurchaseAsync(productId, ItemType.InAppPurchase, payload);

            if (purchase == null)
            {
                return false;
            }
            else
            {
                return true;
            }
        }
        catch (InAppBillingPurchaseException purchaseEx)
        {

        }

        finally
        {
            await billing.DisconnectAsync();
        }
    }

Answer 1

如果第一个try捕获到异常，则有可能绕过您所有的return语句。您可以通过在方法末尾添加返回权来解决此问题：

public async Task<bool> TestMakePurchase(string productId, string payload)
{
    var billing = CrossInAppBilling.Current;
    try
    {
        // Snip
    }
    catch (InAppBillingPurchaseException purchaseEx)
    {

    }
    finally
    {
        await billing.DisconnectAsync();
    }

    // Add this line
    return false;
}

Answer 2

如果try块中发生异常，则代码退出时将没有任何return值。请在return块之后添加finally语句。

Answer 3

您不必在每个条件语句上都调用return。只需使用变量（ purchaseState ）跟踪状态即可。目前尚不清楚引发 InAppBillingPurchaseException 时会发生什么情况。我至少会记录此错误。

public async Task<bool> TestMakePurchase(string productId, string payload)
{   
    var purchaseSuccesful = false;
    var billing = CrossInAppBilling.Current;
    try
    {                                   
        if (await billing.ConnectAsync())
        {                 
            var purchase = await billing.PurchaseAsync(productId, ItemType.InAppPurchase, payload);
            purchaseSuccesful = purchase != null;
        }
    }
    catch (InAppBillingPurchaseException purchaseEx)
    {
        //log this error?
    }
    finally
    {
        await billing.DisconnectAsync();
    }

    return purchaseSuccesful;
}

错误消息：并非所有代码路径都返回一个值

3 个答案: