当我评论Control.CheckForIllegalCrossThreadCalls = False时，我的函数可以正常工作，但未注释时会出现错误
我正在使用BackgroundWorker调用一个将值插入数据库的函数，并且我需要设置Control.CheckForIllegalCrossThreadCalls = False才能使代码正常工作。现在，当我将其设置为false时，其中一个功能无法正常工作。这是错误
从字符串“ -0-1-22”到“日期”类型的转换无效”
当该功能正常工作时
Private Sub btnUpload_Click(sender As Object, e As EventArgs) Handles btnUpload.Click
If Not BackgroundWorker1.IsBusy = True Then
BackgroundWorker1.RunWorkerAsync()
End If
End Sub
我希望该函数附带“ 2019-06-11”作为要插入数据库的日期，而无需使用Control.CheckForIllegalCrossThreadCalls = False
这是代码
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
count_rows()
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
MsgBox("Products imported successfully!", MsgBoxStyle.Information, "Import")
Me.Close()
End Sub
Public Sub count_rows()
import_attendance_sheet(1054)
End Sub
Private Sub import_attendance_sheet(ByVal id As Integer)
ProgressBar1.Minimum = 0
ProgressBar1.Maximum = id
ProgressBar1.Value = 0
Dim path As String = txtPath.Text
Dim excel_connection As OleDbConnection
Dim dt As DataTable
Dim cmd As OleDbDataAdapter
'Dim sql As String
'Dim result As Boolean
Dim emp_type_id As String = ""
Dim branch_id As String = ""
Dim bank_id As String = ""
'Dim sheet_dates As New List(Of String)
'excel_connection = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0; Data Source=" + path + ";Extended Properties=Excel 12.0 Xml; HDR=Yes;")
excel_connection = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties='Excel 12.0 Xml;HDR=No;IMEX=1;';")
cmd = New OleDbDataAdapter("SELECT * FROM [sheet$]", excel_connection)
dt = New DataTable
cmd.Fill(dt)
'initialize symbol row
Dim count As Integer = 6
'Loop through dates(column/header)
For Each column As DataColumn In dt.Columns
Dim colum_name As String = dt.Rows(0)(column.ColumnName).ToString()
'check if column cell is empty
If colum_name = "" Then
'Empty do nothing
Else
'increment symbol row by 1
count = count + 1
'MsgBox(count)
'Loop through rows of a particular date/column/header
For Each r As DataRow In dt.Rows
'check row(empNo) cell is not empty & does not have a string
If r(5).ToString() = "" Or r(5).ToString() = "COY #" Then
'Empty do nothing
Else
'show date | Emp No | Name | symbol index
'MsgBox(colum_name & " " & r(5).ToString() & " " & r(6).ToString() & " " & r(count).ToString())
'do the calculation
Dim employ_id As String = get_employee_id(r(5).ToString)
Dim basic_salary As Decimal = get_employee_basic_salary(r(5).ToString)
Dim staff_type_id As String = get_employee_type_id(r(5).ToString)
Dim days_per_month As Integer = get_employee_days_per_month(staff_type_id)
Dim hours_per_day As Double = get_employee_hours_per_day(staff_type_id)
Dim hourly_rate As Double = basic_salary / days_per_month / hours_per_day
Dim daily_rate As Double = basic_salary / days_per_month
Dim normal_working_hrs As String = get_normal_working_hrs()
Dim shift_duration As String = get_shift_duration()
'get symbol id and its rate
Dim symbol_id As String = get_attendance_symbol_id(r(count).ToString)
Dim symbol_rate As Double = get_attendance_symbol_rate(symbol_id)
Dim symbol_deduction_status As String = get_symbol_deduction_status(symbol_id)
Dim td_amount As Double = 0
If symbol_deduction_status = "DEDUCT" Then
td_amount = hourly_rate
Else
td_amount = 0
End If
Dim overtime As Double = shift_duration - normal_working_hrs
Dim ot_amount As Double = overtime * hourly_rate * symbol_rate
Dim chaka As String = Date.Now.ToString("yyyy")
Dim tsiku As String = Date.Now.ToString("dd")
Dim tsiku_mawu As String = Date.Now.ToString("dddd")
Dim mwezi As String = Date.Now.ToString("MMMM")
' ''insert values into DB
Sql = "INSERT INTO tbl_attendance (employee_id,time_in,time_out,total_hours_worked,overtime,ot_amount,td_amount,attendance_code_id,attendance_code,attendance_date,comment,year,date,day,month,hourly_rate,bsalary,ot_status) VALUES ('" & employ_id & "','" & 0 & "','" & 0 & "','" & shift_duration & "','" & overtime & "','" & ot_amount & "','" & td_amount & "','" & symbol_id & "','" & r(count).ToString & "','" & calc_attendance_date(colum_name) & "','import','" & chaka & "','" & tsiku & "','" & tsiku_mawu & "','" & mwezi & "','" & hourly_rate & "','" & basic_salary & "','" & symbol_rate & "')"
result = save_to_db(Sql)
ProgressBar1.Value = ProgressBar1.Value + 1
'If result Then
' Timer1.Start()
'End If
End If
Next
End If
Next
End Sub
'******* Function which shows the error ****************
Public Function calc_attendance_date(ByVal value As String)
Dim at_date As String = ""
Dim current_month As String = frmMain.cmbMonth.Text
Dim current_year As String = frmMain.cmbYear.Text
Dim mwezi As String
Dim chaka As String
Dim format_day As String = ""
Dim format_month As String = ""
'Date.Now.ToString("yyyy-MM-dd")
'**** find previous month
'when its january
If current_month = "January" And value >= 22 And value <= 31 Then
mwezi = "12"
chaka = Convert.ToInt32(current_year) - 1
at_date = chaka & "-" & mwezi & "-" & value
ElseIf current_month <> "January" And value >= 22 And value <= 31 Then
mwezi = IntMonth() - 1
'day
If value < 10 Then
format_day = "0" & value
ElseIf value >= 10 Then
format_day = value
End If
'format mwezi
If mwezi < 10 Then
format_month = "0" & mwezi
ElseIf mwezi >= 10 Then
format_month = mwezi
End If
chaka = current_year
at_date = chaka & "-" & format_month & "-" & format_day
End If
'**** find current month
If current_month = "January" And value >= 1 And value <= 21 Then
mwezi = IntMonth()
chaka = current_year
'day
If value < 10 Then
format_day = "0" & value
ElseIf value >= 10 Then
format_day = value
End If
'format mwezi
If mwezi < 10 Then
format_month = "0" & mwezi
ElseIf mwezi >= 10 Then
format_month = mwezi
End If
at_date = chaka & "-" & format_month & "-" & format_day
ElseIf current_month <> "January" And value >= 1 And value <= 21 Then
mwezi = IntMonth()
chaka = current_year
'day
If value < 10 Then
format_day = "0" & value
ElseIf value >= 10 Then
format_day = value
End If
'format mwezi
If mwezi < 10 Then
format_month = "0" & mwezi
ElseIf mwezi >= 10 Then
format_month = mwezi
End If
at_date = chaka & "-" & format_month & "-" & format_day
End If
Return at_date
End Function
答案 0 :(得分：0)
您不应尝试通过非UI线程与UI控件进行交互。但是，您可以使用Control.Invoke使代码与UI线程上的那些控件进行交互。在一些地方可以做到这一点。
在import_attendance_sheet内
ProgressBar1.Minimum = 0
ProgressBar1.Maximum = id
ProgressBar1.Value = 0
Dim path As String = txtPath.Text
...
ProgressBar1.Value = ProgressBar1.Value + 1
相反：
Dim path As String
Me.Invoke(
Sub()
ProgressBar1.Minimum = 0
ProgressBar1.Maximum = id
ProgressBar1.Value = 0
path = txtPath.Text
End Sub)
...
Me.Invoke(Sub() ProgressBar1.Value += 1)
所有类似get_employee_id，get_employee_basic_salary，get_employee_type_id之类的功能也可能与UI交互，但是您不提供它们。如果这样做（即从文本框或其他内容返回值），则还需要在它们内部调用。
在calc_attendance_date内
Dim current_month As String = frmMain.cmbMonth.Text
Dim current_year As String = frmMain.cmbYear.Text
相反：
Dim current_month As String
Dim current_year As String
Me.Invoke(
Sub()
current_month = frmMain.cmbMonth.Text
current_year = frmMain.cmbYear.Text
End Sub)
函数IntMonth()对我们也是未知的。同样，如果它从UI读取，则应调用进行UI交互的代码。
仅当绝对必要时（即Control.InvokeRequired时）才调用此方法。请参阅this example，因为他们想使用Me.CheckForIllegalCrossThreadCalls = False（不好！）
更好的是，您可以编写extension methods来自动化Control.InvokeRequired模式