为什么我的GUI不更新？

Question

I am working on creating a program that works its way through thousands of excel cells and splits the strings and forms and fills a chart based on that data. The issue I am having is with the GUI. I have the program split into two separate classes. One handles the excel data while the other is the MainWindow class for the WPF form.

The issue lies in that the MainWindow is not updating with the information as it goes along. It is supposed to update a dialog box and a progress bar showing as it goes through the steps. It does not do anything, but finally appears at the end completely filled as though it had been doing this all along.

It was originally suggested to me that I split the duties into multiple threads and I have done that but it does not seem to work. Is it something in the way I handled the threads? I can post as much of the code as requested but it is a lot so I didn't want to dump it all if it was something simple.

Private Sub runButton_Click(sender As Object, e As RoutedEventArgs) Handles runButton.Click

    If FillCheck() = True Then
        program = New ExcelClass(dataText.Content.ToString, saveText.Content.ToString)
        Dim excelThread As New System.Threading.Thread(AddressOf program.beginProgram)
        excelThread.Start()
        checkUpdate()

    ElseIf FillCheck() = False Then
        MsgBox("You must select both the file to get the data from and the target folder and filename", MsgBoxStyle.OkOnly, "Fill Error")

    Else
        MsgBox("Something has gone terribly amiss. Panic", MsgBoxStyle.OkOnly, "Error")
    End If
End Sub

This code is just the part in the MainWindow class where the second thread is declared and initialized. As I said, it does what it is supposed to do, but all behind-the-scenes when I want it shown in the GUI.

Answer 1

You can use BackgroundWorker class to "send" tasks in background (see MSDN guide for more information). Especially you should look at the WorkerReportsProgress property (it should be set as true), while you are processing data you can report progress using ReportProgress method and you should subscribe to ProgressChanged event to reflect these changes to UI.