如何将输出绑定到异步函数？将参数设置为的常用方法 out 不适用于异步功能。
例
using System;
public static async void Run(string input, TraceWriter log, out string blobOutput)
{
log.Info($"C# manually triggered function called with input: {input}");
await Task.Delay(1);
blobOutput = input;
}
这导致编译错误：
[timestamp] (3,72): error CS1988: Async methods cannot have ref or out parameters
使用绑定（fyi）
{
"bindings": [
{
"type": "blob",
"name": "blobOutput",
"path": "testoutput/{rand-guid}.txt",
"connection": "AzureWebJobsDashboard",
"direction": "out"
},
{
"type": "manualTrigger",
"name": "input",
"direction": "in"
}
],
"disabled": false
}
有几种方法可以做到这一点：
将输出绑定到函数的返回值（最简单）
然后，您只需返回函数中的值即可。您必须将输出绑定的名称设置为 $return 为了使用这种方法
码
public static async Task<string> Run(string input, TraceWriter log)
{
log.Info($"C# manually triggered function called with input: {input}");
await Task.Delay(1);
return input;
}
捆绑
{
"bindings": [
{
"type": "blob",
"name": "$return",
"path": "testoutput/{rand-guid}.txt",
"connection": "AzureWebJobsDashboard",
"direction": "out"
},
{
"type": "manualTrigger",
"name": "input",
"direction": "in"
}
],
"disabled": false
}
将输出绑定到IAsyncCollector
将输出绑定到IAsyncCollector并将项目添加到收集器。
当您有多个输出绑定时，您将需要使用此方法。
码
public static async Task Run(string input, IAsyncCollector<string> collection, TraceWriter log)
{
log.Info($"C# manually triggered function called with input: {input}");
await collection.AddAsync(input);
}
捆绑
{
"bindings": [
{
"type": "blob",
"name": "collection",
"path": "testoutput/{rand-guid}.txt",
"connection": "AzureWebJobsDashboard",
"direction": "out"
},
{
"type": "manualTrigger",
"name": "input",
"direction": "in"
}
],
"disabled": false
}
有几种方法可以做到这一点：
将输出绑定到函数的返回值（最简单）
然后，您只需返回函数中的值即可。您必须将输出绑定的名称设置为 $return 为了使用这种方法
码
public static async Task<string> Run(string input, TraceWriter log)
{
log.Info($"C# manually triggered function called with input: {input}");
await Task.Delay(1);
return input;
}
捆绑
{
"bindings": [
{
"type": "blob",
"name": "$return",
"path": "testoutput/{rand-guid}.txt",
"connection": "AzureWebJobsDashboard",
"direction": "out"
},
{
"type": "manualTrigger",
"name": "input",
"direction": "in"
}
],
"disabled": false
}
将输出绑定到IAsyncCollector
将输出绑定到IAsyncCollector并将项目添加到收集器。
当您有多个输出绑定时，您将需要使用此方法。
码
public static async Task Run(string input, IAsyncCollector<string> collection, TraceWriter log)
{
log.Info($"C# manually triggered function called with input: {input}");
await collection.AddAsync(input);
}
捆绑
{
"bindings": [
{
"type": "blob",
"name": "collection",
"path": "testoutput/{rand-guid}.txt",
"connection": "AzureWebJobsDashboard",
"direction": "out"
},
{
"type": "manualTrigger",
"name": "input",
"direction": "in"
}
],
"disabled": false
}
我还没有声誉可以发表评论，但在上面的Zain Rizvi的代码中，应该说IAsyncCollector：
public static async Task Run(string input, IAsyncCollector<string> collection,
TraceWriter log)
{
log.Info($"C# manually triggered function called with input: {input}");
await collection.AddAsync(input);
}
异步方法可以正常返回值，但是您不应该返回纯类型的值，而是使用Task，如下所示：
public static async Task<string> Run(string input, TraceWriter log, string blobOutput)
{
log.Info($"C# manually triggered function called with input: {input}");
await Task.Delay(1);
blobOutput = input;
return blobOutput;
}