在 Windows Phone 7 中,我试图显示一些 LINQ 查询的状态。我正在使用BackgroundWorker。我在调试窗口中看到了进度更新,但在 UI (TextBlock4.Text) 中没有看到。似乎所有查询结束后进度都会更新。运行查询时 UI 也没有响应。如何避免 UI 冻结?如何在 UI 中显示进度?还有另一种显示查询进度的方法吗?
Partial Public Class pagInvoicesReport
Inherits PhoneApplicationPage
Private WithEvents mWorker As New BackgroundWorker()
Private nJan As Nullable(Of Decimal) = 0
Private nFeb As Nullable(Of Decimal) = 0
Private nMar As Nullable(Of Decimal) = 0
Private nApr As Nullable(Of Decimal) = 0
Private nMay As Nullable(Of Decimal) = 0
Private nJun As Nullable(Of Decimal) = 0
Private nJul As Nullable(Of Decimal) = 0
Private nAug As Nullable(Of Decimal) = 0
Private nSept As Nullable(Of Decimal) = 0
Private nOct As Nullable(Of Decimal) = 0
Private nNov As Nullable(Of Decimal) = 0
Private nDec As Nullable(Of Decimal) = 0
Public Sub New()
InitializeComponent()
mWorker.WorkerReportsProgress = True
End Sub
Private Sub startButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles startButton.Click
mWorker.RunWorkerAsync()
End Sub
Private Sub mWorker_ProgressChanged(ByVal sender As Object, ByVal e As ProgressChangedEventArgs) Handles mWorker_ProgressChanged
TextBlock4.Text = e.ProgressPercentage.ToString() & "%"
System.Diagnostics.Debug.WriteLine(e.ProgressPercentage.ToString() & "%")
End Sub
Private Sub GetGraphValues() Handles mWorker.DoWork
System.Windows.Deployment.Current.Dispatcher.BeginInvoke( _
Sub()
Using theDB As New appContext("Data Source=isostore:/theDB.sdf")
Try
If (Aggregate r In theDB.InvoicesRecords Where r.InvoiceDateTime.Month = 1 And r.InvoiceDateTime.Year = 2012 And r.MainID = 1 Into Sum(CType(r.Cost, Decimal?))) IsNot Nothing Then
nJan = (Aggregate r In theDB.InvoicesRecords Where r.InvoiceDateTime.Month = 1 And r.InvoiceDateTime.Year = 2012 And r.MainID = 1 Into Sum(CType(r.Cost, Decimal?)))
Else
nJan = 0
End If
Catch ex As Exception
MessageBox.Show("There was an error!" & vbCrLf & ex.Message, "Error!", MessageBoxButton.OK)
End Try
End Using
End Sub)
mWorker.ReportProgress(8)
System.Windows.Deployment.Current.Dispatcher.BeginInvoke( _
Sub()
Using theDB As New appContext("Data Source=isostore:/theDB.sdf")
Try
If (Aggregate r In theDB.InvoicesRecords Where r.InvoiceDateTime.Month = 2 And r.InvoiceDateTime.Year = 2012 And r.MainID = 1 Into Sum(CType(r.Cost, Decimal?))) IsNot Nothing Then
nFeb = (Aggregate r In theDB.InvoicesRecords Where r.InvoiceDateTime.Month = 2 And r.InvoiceDateTime.Year = 2012 And r.MainID = 1 Into Sum(CType(r.Cost, Decimal?)))
Else
nFeb = 0
End If
Catch ex As Exception
MessageBox.Show("There was an error!" & vbCrLf & ex.Message, "Error!", MessageBoxButton.OK)
End Try
End Using
End Sub)
mWorker.ReportProgress(17)
System.Windows.Deployment.Current.Dispatcher.BeginInvoke( _
Sub()
Using theDB As New appContext("Data Source=isostore:/theDB.sdf")
Try
If (Aggregate r In theDB.InvoicesRecords Where r.InvoiceDateTime.Month = 12 And r.InvoiceDateTime.Year = 2012 And r.MainID = 1 Into Sum(CType(r.Cost, Decimal?))) IsNot Nothing Then
nDec = (Aggregate r In theDB.InvoicesRecords Where r.InvoiceDateTime.Month = 12 And r.InvoiceDateTime.Year = 2012 And r.MainID = 1 Into Sum(CType(r.Cost, Decimal?)))
Else
nDec = 0
End If
Catch ex As Exception
MessageBox.Show("There was an error!" & vbCrLf & ex.Message, "Error!", MessageBoxButton.OK)
End Try
End Using
End Sub)
mWorker.ReportProgress(100)
End Sub
结束类