vb.net 在 VB 中正确使用 Async/Await
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Using Async/Await correctly in VB
提问by cjw
I am having trouble getting a datatable from a WCF service using Async/Await and loading it into a datagridview. This is my first time doing this, I feel like I am missing something basic. This is the code I have so far:
我无法使用 Async/Await 从 WCF 服务获取数据表并将其加载到 datagridview 中。这是我第一次这样做，我觉得我缺少一些基本的东西。这是我到目前为止的代码：
Private p_oDataService As New SQLService.DataServiceClient
Async Function GetReportDataTable() As Task(Of DataTable)
Try
p_oDataService = New SQLService.DataServiceClient
Dim tDatatable As Task(Of DataTable) = p_oDataService.GetValidationReportsAsync()
Dim dt As DataTable = Await tDatatable
Return dt
Catch ex As Exception
Throw ex
End Try
End Function
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Dim tDT As Task(Of DataTable) = GetReportDataTable()
Dim dt As DataTable = GetReportDataTable.Result
DataGridView1.AutoGenerateColumns = True
DataGridView1.DataSource = dt
Catch ex As Exception
Throw ex
End Try
End Sub
Any help is appreciated!
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回答by Nkosi
You are mixing blocking and async calls. When you call GetReportDataTable.Resultit will deadlock.
您正在混合阻塞和异步调用。当你调用GetReportDataTable.Result它时会死锁。
Event handlers allow you to await async tasks as well so update the event handler...
事件处理程序允许您等待异步任务以及更新事件处理程序...
Private Async Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Try
Dim dt As DataTable = Await GetReportDataTable()
DataGridView1.AutoGenerateColumns = True
DataGridView1.DataSource = dt
Catch ex As Exception
Throw ex
End Try
End Sub
