.ics 文件的响应 .write 不允许代码运行

Question

我正在编写一个应用程序，它通过获取用户输入的数据动态构建 .ICS 文件。我想要做的是将数据保存到数据库中，然后提供 .ICS 文件供用户下载，以便他们可以将其添加到他们的日历中。我希望所有这一切都可以通过单击一个按钮来实现。我运行遇到的问题是，当单击按钮时，它正在写入文件，因此用户可以下载它，但它不会将数据存储到数据库中。它停留在页面上并且不会出现回发。

Public Sub AddToCalendar(ByVal Src As Object, ByVal e As EventArgs)              
Try        

    Dim Subject As String = setDBText(txtSubject.text)
    Dim Comment As String = setDBText(txtComment.text)
    Dim StartDate As String = setDBDate(txtStartDate.value,txtStartTime.text)
    Dim EndDate As String = setDBDate(txtEndDate.value,txtEndTime.text)

    sqlStr = "INSERT INTO tblActivity(Subject,Comment,StartDate,EndDate) " & _
             "VALUES(" & Subject & "," & Comment & "," & StartDate & "," & EndDate &")"
    dc.CommandText = sqlStr
    dc.ExecuteNonQuery()

    lblTest.Text = "New Event Sucessfully Added"                    

    '************
    '** CREATE CODE TO BUILD ICS FILE
    '************
    Dim sbICSFile As StringBuilder = New StringBuilder()
    Dim dtNow As DateTime = DateTime.Now

    sbICSFile.AppendLine("BEGIN:VCALENDAR")
    sbICSFile.AppendLine("VERSION:2.0")
    sbICSFile.AppendLine("PRODID:-//AkonaDev/CalendarAppointment")
    sbICSFile.AppendLine("CALSCALE:GREGORIAN")
    sbICSFile.AppendLine("BEGIN:VEVENT")

    ' Define time zones.
    ' US/Eastern
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Eastern")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0400")
    sbICSFile.AppendLine("TZOFFSETTO:-0500")
    sbICSFile.AppendLine("TZNAME:EST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0500")
    sbICSFile.AppendLine("TZOFFSETTO:-0400")
    sbICSFile.AppendLine("TZNAME:EDT")
    sbICSFile.AppendLine("END:DAYLIGHT")
    sbICSFile.AppendLine("END:VTIMEZONE")

    ' US/Central
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Central")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0500")
    sbICSFile.AppendLine("TZOFFSETTO:-0600")
    sbICSFile.AppendLine("TZNAME:CST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0600")
    sbICSFile.AppendLine("TZOFFSETTO:-0500")
    sbICSFile.AppendLine("TZNAME:CDT")
    sbICSFile.AppendLine("END:DAYLIGHT")

    sbICSFile.AppendLine("END:VTIMEZONE")

    ' US/Mountain
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Mountain")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0600")
    sbICSFile.AppendLine("TZOFFSETTO:-0700")
    sbICSFile.AppendLine("TZNAME:MST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0700")
    sbICSFile.AppendLine("TZOFFSETTO:-0600")
    sbICSFile.AppendLine("TZNAME:MDT")
    sbICSFile.AppendLine("END:DAYLIGHT")
    sbICSFile.AppendLine("END:VTIMEZONE")

    ' US/Pacific
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Pacific")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0700")
    sbICSFile.AppendLine("TZOFFSETTO:-0800")
    sbICSFile.AppendLine("TZNAME:PST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0800")
    sbICSFile.AppendLine("TZOFFSETTO:-0700")
    sbICSFile.AppendLine("TZNAME:PDT")
    sbICSFile.AppendLine("END:DAYLIGHT")
    sbICSFile.AppendLine("END:VTIMEZONE")

    ' Define the event
    sbICSFile.Append("DTSTART;TZID=" + ddlStartTZ.Text + ":")
    sbICSFile.Append(CDATE(txtStartDate.value).Year.ToString())
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Month))
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Day) + "T")
    sbICSFile.AppendLine(ddlStartTime.SelectedValue)

    sbICSFile.Append("DTEND;TZID=" + ddlEndTZ.Text + ":")
    sbICSFile.Append(CDATE(txtStartDate.value).Year)
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Month))
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Day) + "T")
    sbICSFile.AppendLine(ddlEndTime.SelectedValue)

    sbICSFile.AppendLine("SUMMARY:" + txtEventSubject.Text)
    sbICSFile.AppendLine("DESCRIPTION:" + txtEventDescription.Text)
    sbICSFile.AppendLine("UID:1")
    sbICSFile.AppendLine("SEQUENCE:0")

    sbICSFile.Append("DTSTAMP:" + dtNow.Year.ToString())
    sbICSFile.Append(FormatDateTimeValue(dtNow.Month))
    sbICSFile.Append(FormatDateTimeValue(dtNow.Day) + "T")
    sbICSFile.Append(FormatDateTimeValue(dtNow.Hour))
    sbICSFile.AppendLine(FormatDateTimeValue(dtNow.Minute) + "00")

    sbICSFile.AppendLine("END:VEVENT")
    sbICSFile.AppendLine("END:VCALENDAR")    

    Response.ContentType = "text/calendar"
    Response.AddHeader("content-disposition", _
        "attachment; filename=CalendarEvent1.ics")
    Response.Write(sbICSFile)
    Response.End()

Catch exc As Exception
    lblError.text = exc.toString       

End Try

Answer 1

我注意到的第一件事是您的 INSERT 声明似乎有一些问题。（这可能就是代码块中的语法着色看起来不正确的原因。）字符串通常用单引号引起来。这应该会导致抛出异常，所以我不确定它是如何继续过去 ExecuteNonQuery 的。我希望看到更多这样的东西。

sqlStr = "INSERT INTO tblActivity(Subject,Comment,StartDate,EndDate) " & _
         "VALUES('" & Subject & "','" & Comment & "','" & StartDate & "','" & EndDate &"')"

更好的选择是参数化语句。请仔细阅读。您的代码原样容易受到 SQL 注入的攻击。 How does SQLParameter prevent SQL Injection?

Answer 2

我发现响应一次只能做其中一件事情。它不能发送文件和执行服务器代码。所以我所做的是创建一个单独的 "file download" 页面来处理 page_load 上的文件下载。为了将 ICS 文件数据传输到文件下载页面，我创建了一个会话变量，该变量在提交页面的按钮单击时被填充。然后，我向按钮添加了一个 onClientClick 事件，并将其设置为一个 javascript 函数，该函数会打开 window 到文件下载页面的弹出窗口。这允许页面将数据保存到数据库，并通过单击按钮显示文件下载提示。

提交页面

Public Sub AddToCalendar(ByVal Src As Object, ByVal e As EventArgs)              
Try        

    Dim Subject As String = setDBText(txtSubject.text)
    Dim Comment As String = setDBText(txtComment.text)
    Dim StartDate As String = setDBDate(txtStartDate.text,txtStartTime.text)
    Dim EndDate As String = setDBDate(txtEndDate.text,txtEndTime.text)

    sqlStr = "INSERT INTO tblActivity(Subject,Comment,StartDate,EndDate) " & _
             "VALUES(" & Subject & "," & Comment & "," & StartDate & "," & EndDate &")" 
    dc.CommandText = sqlStr
    dc.ExecuteNonQuery()

    lblTest.Text = "New Event Sucessfully Added"                    

    '************
    '** CREATE CODE TO BUILD ICS FILE
    '************
    Dim sbICSFile As StringBuilder = New StringBuilder()
    Dim dtNow As DateTime = DateTime.Now

    sbICSFile.AppendLine("BEGIN:VCALENDAR")
    sbICSFile.AppendLine("VERSION:2.0")
    sbICSFile.AppendLine("PRODID:-//AkonaDev/CalendarAppointment")
    sbICSFile.AppendLine("CALSCALE:GREGORIAN")
    sbICSFile.AppendLine("BEGIN:VEVENT")

    ' Define time zones.
    ' US/Eastern
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Eastern")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0400")
    sbICSFile.AppendLine("TZOFFSETTO:-0500")
    sbICSFile.AppendLine("TZNAME:EST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0500")
    sbICSFile.AppendLine("TZOFFSETTO:-0400")
    sbICSFile.AppendLine("TZNAME:EDT")
    sbICSFile.AppendLine("END:DAYLIGHT")
    sbICSFile.AppendLine("END:VTIMEZONE")

    ' US/Central
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Central")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0500")
    sbICSFile.AppendLine("TZOFFSETTO:-0600")
    sbICSFile.AppendLine("TZNAME:CST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0600")
    sbICSFile.AppendLine("TZOFFSETTO:-0500")
    sbICSFile.AppendLine("TZNAME:CDT")
    sbICSFile.AppendLine("END:DAYLIGHT")

    sbICSFile.AppendLine("END:VTIMEZONE")

    ' US/Mountain
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Mountain")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0600")
    sbICSFile.AppendLine("TZOFFSETTO:-0700")
    sbICSFile.AppendLine("TZNAME:MST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0700")
    sbICSFile.AppendLine("TZOFFSETTO:-0600")
    sbICSFile.AppendLine("TZNAME:MDT")
    sbICSFile.AppendLine("END:DAYLIGHT")
    sbICSFile.AppendLine("END:VTIMEZONE")

    ' US/Pacific
    sbICSFile.AppendLine("BEGIN:VTIMEZONE")
    sbICSFile.AppendLine("TZID:US/Pacific")
    sbICSFile.AppendLine("BEGIN:STANDARD")
    sbICSFile.AppendLine("DTSTART:20071104T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11")
    sbICSFile.AppendLine("TZOFFSETFROM:-0700")
    sbICSFile.AppendLine("TZOFFSETTO:-0800")
    sbICSFile.AppendLine("TZNAME:PST")
    sbICSFile.AppendLine("END:STANDARD")
    sbICSFile.AppendLine("BEGIN:DAYLIGHT")
    sbICSFile.AppendLine("DTSTART:20070311T020000")
    sbICSFile.AppendLine("RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3")
    sbICSFile.AppendLine("TZOFFSETFROM:-0800")
    sbICSFile.AppendLine("TZOFFSETTO:-0700")
    sbICSFile.AppendLine("TZNAME:PDT")
    sbICSFile.AppendLine("END:DAYLIGHT")
    sbICSFile.AppendLine("END:VTIMEZONE")

    ' Define the event
    sbICSFile.Append("DTSTART;TZID=" + ddlStartTZ.Text + ":")
    sbICSFile.Append(CDATE(txtStartDate.value).Year.ToString())
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Month))
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Day) + "T")
    sbICSFile.AppendLine(ddlStartTime.SelectedValue)

    sbICSFile.Append("DTEND;TZID=" + ddlEndTZ.Text + ":")
    sbICSFile.Append(CDATE(txtStartDate.value).Year)
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Month))
    sbICSFile.Append( _
        FormatDateTimeValue(CDATE(txtStartDate.value).Day) + "T")
    sbICSFile.AppendLine(ddlEndTime.SelectedValue)

    sbICSFile.AppendLine("SUMMARY:" + txtEventSubject.Text)
    sbICSFile.AppendLine("DESCRIPTION:" + txtEventDescription.Text)
    sbICSFile.AppendLine("UID:1")
    sbICSFile.AppendLine("SEQUENCE:0")

    sbICSFile.Append("DTSTAMP:" + dtNow.Year.ToString())
    sbICSFile.Append(FormatDateTimeValue(dtNow.Month))
    sbICSFile.Append(FormatDateTimeValue(dtNow.Day) + "T")
    sbICSFile.Append(FormatDateTimeValue(dtNow.Hour))
    sbICSFile.AppendLine(FormatDateTimeValue(dtNow.Minute) + "00")

    sbICSFile.AppendLine("END:VEVENT")
    sbICSFile.AppendLine("END:VCALENDAR")    

    '** SET TO SESSION VARIABLE INSTEAD OF CALLING RESPONSE.WRITE **
    Session("ICSFile") = sbICSFile.ToString

Catch exc As Exception
    lblError.text = exc.toString       

End Try
End Sub

ICS 文件下载页面

Sub Page_Load(Src As Object, E As EventArgs)                              
Try
    '** GET ICS FILE FROM SESSION VARIABLE
    Dim ICSFile As String = Session("ICSFile").ToString

    Response.ContentType = "text/calendar"
    Response.AddHeader("content-disposition", "attachment; filename=CalendarEvent1.ics")
    Response.Write(ICSFile)
    Response.End()

Catch exc As Exception
    lblError.text = exc.toString
End Try         
End Sub

HTML

asp:按钮 ID="btnAddToCalendar" runat="server" OnClick="AddToCalendar" OnClientClick="javascript:DownloadICS();" Text="Add To Calendar" />

JavaScript

<script type="text/javascript" language="javascript">
 function DownloadICS() {
    popUp("ics_download.aspx", 300, 300);
}

function popUp(url, width, height) {
    if (window.featWin && !window.featWin.closed) {
        window.featWin.close();
        featWin = window.open(url, "win", 'toolbar=0,location=1,directories=0,status=0,menubar=0,scrollbars=1,resizable=1,width=' + width + ',height=' + height);
        selfWin = self;
        featWin.focus();
    }
    else {
        featWin = window.open(url, "win", 'toolbar=0,location=1,directories=0,status=0,menubar=0,scrollbars=1,resizable=1,width=' + width + ',height=' + height);
        selfWin = self;
        featWin.focus();
    }
}
function closeWin() {
    if (window.featWin && !window.featWin.closed) {
        window.featWin.close();
    }
}

.ics 文件的响应 .write 不允许代码运行

Response .write for .ics file not allowing code to run

vb.net

icalendar

response.write

.ics 文件的响应 .write 不允许代码 运行

Response .write for .ics file not allowing code to run

vb.net

icalendar

response.write

.ics 文件的响应 .write 不允许代码运行