如何从其他表格vb.net获取SelectedIndex

Question

我正在尝试一次添加员工和他们的工作。我正在尝试将两个记录都插入到一个ID表中。我有一个“查找”按钮，可以在另一个装有乔布斯的表单上打开一个组合框。选择之后，将在第一个表单上填充txtJobName文本框。那用应有的工作名称填充，但是我不能拉SelectedIndex插入到TJobEmployees表中。

'Variables
Dim strSelect As String
Dim strInsert As String
Dim strFirstName As String = ""
Dim strLastName As String = ""
Dim strJob As String = frmSelectJobName.strSelectedJob
Dim intJobID As Integer
Dim cmdSelect As OleDb.OleDbCommand
Dim cmdInsert As OleDb.OleDbCommand
Dim dr As OleDb.OleDbDataReader
Dim intNextHighestRecordID As Integer
Dim intRowsAffected As Integer
Dim result As DialogResult


strFirstName = txtFirstName.Text
strLastName = txtLastName.Text
strJob = txtJobName.Text
intJobID = CInt(frmSelectJobName.lstJobs.SelectedValue)

If Validation() = True Then

  If OpenDatabaseConnectionSQLServer() = False Then

    ' No, warn the user ...
    MessageBox.Show(Me, "Database connection error." & vbNewLine &
                                "The application will now close.",
                                Me.Text + " Error",
                                MessageBoxButtons.OK, MessageBoxIcon.Error)

    ' and close the form/application
    Me.Close()

  End If

  ' always ask before adding!!!!
  result = MessageBox.Show("Are you sure you want to Add Employee: Job-" & txtJobName.Text & "?", "Confirm Submission", MessageBoxButtons.YesNoCancel, MessageBoxIcon.Question)

  ' this will figure out which button was selected. Cancel and No does nothing, Yes will allow insert
  Select Case result
    Case DialogResult.Cancel
      MessageBox.Show("Action Canceled")
    Case DialogResult.No
      MessageBox.Show("Action Canceled")
    Case DialogResult.Yes

      strSelect = "SELECT MAX(intEmployeeID) + 1 AS intNextHighestRecordID " &
                    " FROM TEmployees"

      ' Execute command
      cmdSelect = New OleDb.OleDbCommand(strSelect, m_conAdministrator)
      dr = cmdSelect.ExecuteReader

      ' Read result( highest ID )
      dr.Read()

      ' Null? (empty table)
      If dr.IsDBNull(0) = True Then

        ' Yes, start numbering at 1
        intNextHighestRecordID = 1

      Else

        ' No, get the next highest ID
        intNextHighestRecordID = CInt(dr.Item(0))

      End If
      ' add the child record
      strInsert = "Insert into TEmployees (intEmployeeID, strFirstName, strLastName)" &
        " Values (" & intNextHighestRecordID & ",'" & strFirstName & "'," & "'" & strLastName & "')"

      cmdInsert = New OleDb.OleDbCommand(strInsert, m_conAdministrator)
      intRowsAffected = cmdInsert.ExecuteNonQuery()
      'add the parent record
      strInsert = "Insert into TJobEmployees (intJobID, intEmployeeID)" &
                " Values (" & intJobID & ",'" & intNextHighestRecordID & "')"

      ' Insert the record(s) 
      cmdInsert = New OleDb.OleDbCommand(strInsert, m_conAdministrator)
      intRowsAffected = cmdInsert.ExecuteNonQuery()

      If intRowsAffected > 0 Then
        MessageBox.Show("Job has been added")
        Me.Close()
      End If

  End Select

  CloseDatabaseConnection()

  Form1_Load(sender, e)

End If

Answer 1

您应该对该代码进行很多重构。从此开始，它将帮助您到达想要去的地方：

• 丢弃过时的匈牙利符号。
• 让工作选择器窗体公开两个属性：SelectedJobName和SelectedJobID
• 实例化作业选择器表格的实例：Using f As New frmSelectJobName
• 从属性中选择选定的值：例如selectedJobID = f.SelectedJobID
• 询问用户是否真的要添加Employee 之前验证和连接检查。
• 您正在使用SQL Server。使用SqlClient名称空间中的对象代替OleDb。
• 在数据库中将您的员工ID字段声明为IDENTITY字段，因此您不必使用hacky MAX(ID) + 1。
• 使用存储过程进行查询。当前方法可用于SQL注入。尽管您仍然可以使用内联SQL，但我发现SP更可取。
• 返回添加到员工表中的员工的SCOPE_IDENTITY。这为您提供了添加的员工的主键值。
• 使用Using构造实例化所有SqlClient对象。声明并在本地向Sub / Function（而不是其他地方）打开SqlConnection。
• 无论Form_Load（）中有什么，将其放在单独的Sub中，然后调用该Sub。您正在传递sender，并且从您的代码段中，我不知道此代码在什么事件中。

执行这些操作，如果问题仍然存在，请使用重构的代码更新您的原始帖子，我们将通过编辑答案来继续提供帮助。