当我使用后台工作程序时出现问题

本文介绍了当我使用后台工作程序时出现问题的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 当我使用后台工作程序时，我得到了不清楚的消息'跨线程操作无效：控制'Panel4'从线程以外的线程访问是创建的。 但是如果按常规到正常按钮它工作正常但我在完成过程后挂起这个过程一切都可以使用。 使用后台工作人员的正确方法是什么？ 我尝试了什么： 私人 Sub BtnOk_Click（发件人作为 对象，e As EventArgs）句柄 BtnOk.Click ' 尝试 如果 BW.IsBusy = True 然后 如果 MsgBox（ 有一个进程正在运行，你想杀死进程吗？，MsgBoxStyle.YesNo + MsgBoxStyle.Information， Process）= MsgBoxResult.Yes 然后 BW.CancelAsync（） 结束 如果 Else BW.RunWorkerAsync（） 结束 如果 结束 Sub < pre> Private Sub BW_DoWork（发送者作为 对象，e As System.ComponentModel.DoWorkEventArgs）句柄 BW.DoWork 如果 不 conn.State = ConnectionState.Open 然后 conn.Open（） SaveInto.Connection = conn SaveInto.CommandText = DELETE FROM TrialBalance SaveInto.ExecuteNonQuery（） 选择 案例 Period_Choice 案例 0 ' Uptodate 选择 案例 AllBr_Status 案例 True 选择 案例 RepType 案例 0 选择 案例 Level_Choice 案例 1 ' سلكتللمستوىالاولكاجمالياتبدونتحديدايفرع Dim Account_Code，Account_Name As Stri ng Dim Selected_row 作为 Boolean PB.Maximum = Me .AccountsList.Rows.Count PB.Visible = True 对于 每个 r1 作为 DataGridViewRow 在 我 .AccountsList.Rows Selected_row = r1.Cells（ 0 ）。值 Account_Code = Trim（r1.Cells（ 1 ）。值） Account_Name =修剪（r1.Cells（ 2 ）。值） 如果 Selected_row = True 然后 SaveInto.CommandText = INSERT INTO TrialBalance（帐户，名称，OpenBalance）（SELECT Main_Gr_Code，Main_Gr_Name，Sum（ISNULL（OP_BAL _&修剪（CurYear）& ，0.00）） FROM Acc_OBAL GROUP BY Main_Gr_Code，Main_Gr_Name 拥有Main_Gr_Code ='&修剪（Account_Code）& '） 如果 不 conn.State = ConnectionState.Open 然后 conn.Open（） SaveInto.ExecuteNonQuery （） SaveInto.CommandText = 更新TrialBalance SET TransactionBalance = ISNULL（（SELECT SUM（ Dr_Acc_Value） - sum（Cr_Acc_Value）As Tot 来自JV_QRY Group By Main_Gr_Code，JV_Year HAVING Main_Gr_Code ='& Trim（Account_Code）& '并且JV_Year ='& CurYear& '），0.00）其中Account ='&修剪（Account_Code）& ' 如果 不 conn.State = ConnectionState.Open 然后 conn.Open（） SaveInto.ExecuteNonQuery（） 结束 如果 PB.Value + = 1 下一步 PB.Visible = 错误 PB.Value = 0 解决方案 您只能从创建它们的线程访问UI控件 - U.我线程。如果你试图在后台工作者中做任何事情 - 这是一个不同的线程 - 你将得到一个交叉线程例外。 而是使用 BackgroundWorker。 ReportProgress方法 [ ^ ]将信息传递给UI线程并让它处理UI更新。 似乎你的问题被定义为：如何使用多线程？ 检查： 如何：对Windows窗体控件进行线程安全调用 [ ^ ] 如何：使用后台线程搜索文件 [ ^ ] 这也很有用： c＃ - 跨线程操作无效：从其创建的线程以外的线程访问控件 - Stack Overflow [ ^ ] Hi,When i am using background worker i got unclear message 'Cross-thread operation not valid: Control 'Panel4' accessed from a thread other than the thread it was created on.but if take the routine to the normal button it is working perfectly but i got hang while the process then after finishing the process everything can be usable.what is the correct way to use Background worker?What I have tried:Private Sub BtnOk_Click(sender As Object, e As EventArgs) Handles BtnOk.Click 'Try If BW.IsBusy = True Then If MsgBox("There is a process is running, Do you like to kill the process?", MsgBoxStyle.YesNo + MsgBoxStyle.Information, "Process") = MsgBoxResult.Yes Then BW.CancelAsync() End If Else BW.RunWorkerAsync() End If End Sub<pre>Private Sub BW_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BW.DoWork If Not conn.State = ConnectionState.Open Then conn.Open() SaveInto.Connection = conn SaveInto.CommandText = "DELETE FROM TrialBalance" SaveInto.ExecuteNonQuery() Select Case Period_Choice Case "0" 'Uptodate Select Case AllBr_Status Case True Select Case RepType Case "0" Select Case Level_Choice Case "1" 'سلكت للمستوى الاول كاجماليات بدون تحديد اي فرع Dim Account_Code, Account_Name As String Dim Selected_row As Boolean PB.Maximum = Me.AccountsList.Rows.Count PB.Visible = True For Each r1 As DataGridViewRow In Me.AccountsList.Rows Selected_row = r1.Cells(0).Value Account_Code = Trim(r1.Cells(1).Value) Account_Name = Trim(r1.Cells(2).Value) If Selected_row = True Then SaveInto.CommandText = "INSERT INTO TrialBalance(Account,Name,OpenBalance) (SELECT Main_Gr_Code,Main_Gr_Name,Sum(ISNULL(OP_BAL_" & Trim(CurYear) & ",0.00)) FROM Acc_OBAL GROUP BY Main_Gr_Code,Main_Gr_Name HAVING Main_Gr_Code = '" & Trim(Account_Code) & "')" If Not conn.State = ConnectionState.Open Then conn.Open() SaveInto.ExecuteNonQuery() SaveInto.CommandText = "Update TrialBalance SET TransactionBalance = ISNULL((SELECT SUM(Dr_Acc_Value) - sum(Cr_Acc_Value) As Tot From JV_QRY Group By Main_Gr_Code, JV_Year HAVING Main_Gr_Code = '" & Trim(Account_Code) & "' And JV_Year = '" & CurYear & "'),0.00) where Account = '" & Trim(Account_Code) & "'" If Not conn.State = ConnectionState.Open Then conn.Open() SaveInto.ExecuteNonQuery() End If PB.Value += 1 Next PB.Visible = False PB.Value = 0 解决方案 You can only access UI controls from the thread on which they were created - the UI thread. If you try to do anything at all with them from within a background worker - which is a different thread - you will get a cross threading exception.Instead use the BackgroundWorker.ReportProgress method[^] to pass the information to the UI thread and let it deal with UI updates.Seems your problem is defined as: How to use multithreading?Check this:How to: Make Thread-Safe Calls to Windows Forms Controls[^]How to: Use a Background Thread to Search for Files[^]This can be useful too:c# - Cross-thread operation not valid: Control accessed from a thread other than the thread it was created on - Stack Overflow[^] 这篇关于当我使用后台工作程序时出现问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！