多线程同步求教大家，多谢！

 Public Class 趋势图Private Sub sdnd()        Dim VV As New XTHTHS        Call VV.TYZHDY(UCase(ISTRNN(istr, Threadnew)), Threadnew)    End Sub    Private Function ISTRNN(ByVal NSTRW As String, ByVal ISH As Short) As String        Dim w1 As Integer, w2 As Integer        Dim tmp As String        tmp = "{" & ZBGH(ISH) & "}" & vbCrLf        w1 = InStr(UCase(NSTRW), tmp) : w2 = InStr(w1, UCase(NSTRW), "ABCDEFGHIJKLMNOPQRSTUVWSYZ{}[]")        ISTRNN = Mid(UCase(NSTRW), w1 + Len(tmp), w2 - w1 - Len(tmp) - 1)    End Function    Public Sub drawlozt()        Dim adsa As DateTime = Now        hqs.start = IIf(MaxSize > EveryScreenDay, MaxSize - EveryScreenDay, 0) '保证每屏显示EveryScreenDay天数据        If hqs.start + EveryScreenDay > UBound(hq) Then            hqs.endd = UBound(hq)        Else            hqs.endd = hqs.start + EveryScreenDay        End If        If GetMaxValue(hqs) Then            PDTIANSHU = True            Tabbmp = New Bitmap(Pichqk.Width, Pichqk.Height)            GTabbmp = Graphics.FromImage(Tabbmp)            Kbim = Tabbmp.Clone            GKbim = Graphics.FromImage(Kbim)            If hzzb1 = True Then                If hdzb = True Then                    Dim a As Threading.Thread                    PDXCJS = True  '全局变量                    For ii As Short = 1 To 5                        Threadnew = ii - 1                        a = New Threading.Thread(AddressOf Me.sdnd)                        a.Name = ii                        a.Start()  每个线程调用同一个类模块执行一个计算（我的代码执行时不能正确执行）                        '我想当在PDXCJS = False时执行下一个线程                     Next                 End If         End IfEnd SubEND CLASSPublic Class XTHTHS'.....'.....PDXCJS = False  '全局变量 传递给“趋势图”执行下一个线程END CLASS

Private Sub sdnd()        Dim VV As New XTHTHS        VV.PDXCJS =false        dim ii as integer=0        while(not VV.PDXCJS andalso ii<6)           Call VV.TYZHDY(UCase(ISTRNN(istr, Threadnew)), Threadnew) '这个函数里面你一开始把PDXCJS 变量置为true，执行完再置为false           ii=ii+1        end while    End Sub