Question

我正在尝试找到一种基于选择单选按钮来运行某些代码的方法。我在组合框中有几个单选按钮，它们将根据选择运行不同的代码。现在，作为一个相当新的VB.NET用户，我正在努力正确编码。

使用IF语句或SELECT CASE语句会更好吗？我尝试使用标志设置为布尔值来指示是否选择了button1，设置了flag = true。就我而言。我正在使用CheckedChanged事件来处理事件更改。我已经包含了一些代码，如果有人能让我开始，我将不胜感激。非常感谢。

Private Sub rdbBoxReturn_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles rdbBoxReturn.CheckedChanged

'code goes here
 flagBoxReturn = True

End Sub


Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click

        Try

            If flagBoxReturn = True Then
                MessageBox.Show(CStr(flagBoxReturn))
                Return

            Else

                DBConnection.connect()
                sql = "SELECT MAX([Id]) from Request Boxes WHERE Customer = '" & cmbCustomer.Text & "' "

                'MessageBox.Show(cmbCustomer.Text)
                'sql = "INSERT INTO [Requests]  ("")"
                'Dim sql As String = "SELECT * from Boxes WHERE Customer = ? AND Status = 'i'"

                Dim cmd As New OleDb.OleDbCommand

                Dim id As String
                Dim requestor As String = "DEMO"
                Dim intake As String = "I"
                Dim status As String = "O"

                'cmd.Parameters.AddWithValue("@p1", cmbCustomer.Text)

                cmd.CommandText = sql
                cmd.Connection = oledbCnn
                dr = cmd.ExecuteReader


                'lvSelectRequestItems.Items.Clear()

                While dr.Read()

                    id = CStr(CInt(dr.Item(0).ToString))
                    id = String.Format("{0:D6}", (Convert.ToInt32(id) + 1))
                    'id = CStr(CDbl(id) + 1)

                End While

                MessageBox.Show(CStr(id))

                dr.Close()

                sql = "INSERT INTO [Request Boxes] ([Request no], Customer, Dept, [Type], [Service level], [Date-time received], [Received by], [Date-time due], Quantity, [Cust requestor], Status ) " &
                "VALUES ('" & id & "', '" & cmbCustomer.Text.ToUpper & "', '" & cmbDept.Text & "', '" & intake.ToString & "', '" & rbServiceLevel.ToString & "', '" & dtpDateReceived.Value & "', '" & requestor.ToString & "', '" & dtpDateDue.Value & "', '" & txtBoxQuantity.Text & "', '" & requestor.ToString & "', '" & status & "')"

                cmd.CommandText = sql
                cmd.ExecuteNonQuery()

                cmd.Dispose()
                oledbCnn.Close()

                flagBoxReturn = False

                MessageBox.Show("Your record number: " & id & " Was entered successfully")

            End If

        Catch ex As Exception

            MessageBox.Show(ex.Message)

        End Try

    End Sub

Answer 1

这样的事情怎么样......

Public Enum SaveOption As Int32
  DoNothing = 0
  DoSomething = 1    '  Obviously rename this to something that makes sense in your situation.
End Enum

Public Function GetSaveOption() As SaveOption
  Dim result As SaveOption = SaveOption.DoNothing

  If rdbBoxReturn.Checked Then
    result = DoSomething
  End If
  '  Add as many if statements her to cover all your radio buttons.

  Return result
End Function



Private Sub btnSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSave.Click
  Select Case GetSaveOption
    Case SaveOption.DoNothing
      Exit Sub

    Case SaveOption.DoSomething
      ' Your save code here
  End Select
End Sub

此方法通过将UI元素状态转换为程序状态，使您的代码更具可读性。

Answer 2

如果比较次数很少，则切换语句会更好如果你有一个单选按钮列表控件，那就更好了 switch语句可以传递索引变量（Radio的SelectedIndex属性）按钮列表）但该控件在Web表单中可用，或者可以在win表单中使用如果你找到一些免费的用户/自定义控件等。

所以在你的情况下，最好使用if else语句

如果或基于单选按钮的case语句单击

2 个答案: