蓝老师，我想借助狐友分享的销售开票系统，改成新建账套的功能，这一步实现了，但用自定义登录窗口登录时总提示错误：

.NET Framework 版本：4.0.30319.36543

Foxtable 版本：2022.7.3.1

错误所在事件：

详细错误信息：

This row has been removed from a table and does not have any data.  BeginEdit() will allow creation of new data in this row.

自定义登录窗口的“确定”按钮代码是：

Dim tx1 As WinForm.ComboBox = e.Form.Controls("ComboBox1")

Dim user As String = tx1.text

Dim sss As String = e.Form.Controls("ComboBox2").text \'sss项目文件名

Dim tx2 As WinForm.TextBox = e.Form.Controls("TextBox2")

Dim pows As String = tx2.text

Dim dl As WinForm.Button = e.Form.Controls("Button1")

Dim dt As DataTable = DataTables("用户表")

Dim dr As DataRow

If user = "" Then

    MessageBox.show("请输入用户名称!", "提示", MessageBoxButtons.OK, MessageBoxIcon.Error)

    Return

Else

    dr = dt.find("用户名称=\'" & user & "\'")

    If dr IsNot Nothing Then

        If pows = dr("密码") Then

            PopMessage("登陆成功", "提示", PopIconEnum.Infomation, 1)

            dr("登陆时间") = Date.Now

            dr("登陆账套") = sss \'sss项目文件名

            dr.Save()

            usna = user

            syscmd.project.open(ProjectFile, sss)\'打开项目，ProjectFile返回已经打开的项目文件名

            e.Form.close

            \'syscmd.project.Exit(True)

            Return

        Else

            MessageBox.show("密码错误", "提示")

            Return

        End If

    Else

        MessageBox.show("用户不存在!", "提示")

        Return

AfterOpenProject：

Forms("主窗口2").open()

MainTable = Tables("用户表")

If OpenFileArgs.count > 0 Then

Else

Forms("登陆").Open()

If usna = "" Then

syscmd.project.Exit()

Return

End If

End If

Dim dr As DataRow = DataTables("用户表").find("用户名称=\'" & usna & "\'")

If dr IsNot Nothing Then

StatusBar.Message1 = "用户:" & usna & "   " & "当前账套:" & dr("登陆账套")

End If

StatusBar.Message2 = "  登陆日期:" & Date.Today