How do I make async and await work in VB.NET

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VB

 Dim taskList = New List(Of Task)()

 For Each pair As KeyValuePair(Of String, String) In pairs
 taskList.Add(Task.Factory.StartNew(
 Sub() 
 geXml.Execute()//which returns List(Of String) 
 End Sub
 Next
In this case how can I implement Async Wait call, because I have to use this List(Of String) becasue it is getting data from storage procedure.

What I have tried:

For Each pair As KeyValuePair(Of String, String) In pairs
taskList.Add(Task.Factory.StartNew(
Sub()
geXml.Execute()//which returns List(Of String)
End Sub
Next

Posted 24-Aug-16 3:21am

Member 11491784

Updated 24-Aug-16 4:12am

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Richard Deeming · Answer 1 · 2016-08-24T04:12:00

Solution 1

Assuming you want to await the taskList and get the results, something like this should work:

VB.NET

Dim taskList As New List(Of Task(Of List(Of String)))()

For Each pair As KeyValuePair(Of String, String) In pairs
    taskList.Add(Task.Run(Function() geXml.Execute()))
Next

Dim results As IList(Of IList(Of String)) = Await Task.WhenAll(taskList)

Posted 24-Aug-16 4:12am

Richard Deeming

Comments

Member 11491784 24-Aug-16 10:58am

Hi I am unable to use because its saying that run is not memebr of System.Threading.Tasks
taskList.Add(Task.Run( instead of this I am using this
Task.Factory.StartNew(Function()

And also Await Task.WhenAll(taskList) is not available

Can i use somthing liek this Dim results As IList(Of IList(Of String)) = Await Task.WaitAll(taskList)

Richard Deeming 24-Aug-16 11:00am

Then you're not using .NET 4.5?

Which version of Visual Studio are you using?

Richard Deeming 24-Aug-16 12:56pm

If you're not using Visual Studio 2015, then you can't use Async / Await.

If you're using Visual Studio 2015, but targeting .NET 4.0, you'll need to add the Microsoft.Bcl.Async[^] NuGet package. Some methods such as Task.Run will belong to a class called TaskEx instead. You'll also need to make sure your users have KB2468871[^] installed.