Question Backgroundworker / Threading Question

[Sterling33]

Hi All,

I'm hoping someone maybe able to help me out with the following problem. I have a application that I've been working on that utilizes a Class called 'User'. This class has several Functions that are called by a Click event on the main form. These functions must run and return required data that another function call will need later in the click event.

My problem is that when these funtions are called, the Window of the app freezes up until it completes. I have been reading into Backgroundworkers, and believe this maybe my answer, but am either not totally comprehending the concept of Backgroundworkers, or/and I do not see any info on how to implement it where I can run one function at a time without another kicking off. Like I said before, each function is dependant on another.

Private Sub btnValidateUser_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnValidateUser.Click
        If tbxBLUsername.Text.Length = 0 Then
            'set back cursor to default
            Me.Cursor() = Cursors.Default

            MessageBox.Show("You must specify a BladeLogic user account name. Please enter a valid BladeLogic account, and validate again.")
            Exit Sub
        End If

        'set cursor to application starting
        Me.Cursor() = Cursors.AppStarting
        blnValidationResult = BLUser.IsUserExists(BLUser.BLAdminAcct, BLUser.BLAdminPswd, BLUser.BLAdminRole, tbxBLUsername.Text)
        MsgBox(blnValidationResult)
        If blnValidationResult = False Then
            'set back cursor to default
            Me.Cursor() = Cursors.Default

            MessageBox.Show("The user account specified does not exist in BladeLogic. Please verify spelling, and validate again.")
            BLUser.ClearRoleNamesAndIds()
            Exit Sub
        Else
            'set back cursor to default
            Me.Cursor() = Cursors.Default
            cmbxAdminRole.Enabled = True
        End If

        BLUser.getAssignedUserRoles(BLUser.UserName)
End Sub

The above is a small sample of the click event with a call to 2 of the user functions (isUserExists and getAssignedUserRoles). isUserExists must run and return true before getAssignedUserRoles runs.

Below are the 2 functions from the User Class

Function IsUserExists(ByVal strPassedUsername As String, ByVal strPassedUserPassword As String, ByVal strPassedUserRole As String, ByVal strQueriedBLUserName As String) As Boolean
        Dim prcInfo As New System.Diagnostics.ProcessStartInfo("blcli.exe", "-u " & strPassedUsername & " -s " & strPassedUserPassword & " -r " & strPassedUserRole & " RBACUser isUserExists " & strQueriedBLUserName)

        prcInfo.RedirectStandardOutput = True
        prcInfo.WindowStyle = ProcessWindowStyle.Hidden
        prcInfo.CreateNoWindow = True
        prcInfo.UseShellExecute = False

        Dim prcBLCLI As System.Diagnostics.Process

        prcBLCLI = System.Diagnostics.Process.Start(prcInfo)

        Dim objStreamOutput As System.IO.StreamReader = prcBLCLI.StandardOutput
        Dim strOutput As Boolean = objStreamOutput.ReadToEnd

        prcBLCLI.WaitForExit()
        If prcBLCLI.HasExited Then
            If strOutput = True Then
                strBLUsername = strQueriedBLUserName
            Else
                strBLUsername = Nothing
            End If

            Return strOutput
        End If

        prcBLCLI.Close()
    End Function

Sub getAssignedUserRoles(ByVal strPassedBLUserName As String)
        findRoleIdsForUser(strPassedBLUserName)

        ReDim arrRoleNames(arrUserRoleIds.Length - 1)

        Dim intRoleIdCounter As Integer = 0

        Do Until intRoleIdCounter = arrUserRoleIds.Length - 1
            For Each strElement As String In arrUserRoleIds
                arrRoleNames(intRoleIdCounter) = findRoleNameById(strElement)
                If intRoleIdCounter = arrUserRoleIds.Length - 1 Then
                    Exit Do
                End If
                intRoleIdCounter = intRoleIdCounter + 1
            Next
        Loop
    End Sub

Any help would be most appreciated.

Regards,
Ed

 

[MattP]

Do a search on the forums for BackgroundWorker.

msdn: BackgroundWorker

The basic process is to drag a BackgroundWorker to your form and put what you want to run in the background in its DoWork event.