VB.net更改ComboBox選擇的值並顯示

Question

我在vb.net中使用以下代碼：

Function GetBillingMonthsGrouped() As List(Of BillingMonthsGrouped)
        Dim conn = New MySqlConnection()
        Dim conn2 = New MySqlConnection()
        Dim myCommand, myCommand2 As New MySqlCommand
        Dim reader, reader2 As MySqlDataReader
        Dim SQL As String

        conn.ConnectionString = "server=" + global_variables.web_server_ip + "; user id=" + global_variables.web_server_username + "; password=" + global_variables.web_server_password + "; database=" + global_variables.web_server_database + "; "
        conn2.ConnectionString = "server=" + global_variables.web_server_ip + "; user id=" + global_variables.web_server_username + "; password=" + global_variables.web_server_password + "; database=" + global_variables.web_server_database + "; "

        Dim billingMonthsGrouped = New List(Of BillingMonthsGrouped)

        'customers
        conn.Open()
        SQL = "select MONTH(timestamp) from billing group by MONTH(timestamp) order by MONTH(timestamp) ASC "
        myCommand.Connection = conn
        myCommand.CommandText = SQL
        reader = myCommand.ExecuteReader
        While reader.Read()
            billingMonthsGrouped.Add(New BillingMonthsGrouped(reader.GetString(0), MonthName(reader.GetString(0))))
        End While
        conn.Close()

        Return billingMonthsGrouped
    End Function
    Public Class BillingMonthsGrouped
        Public Sub New(ByVal id As String, ByVal name As String)
            mID = id
            mName = name
        End Sub

        Private mID As String
        Public Property ID() As String
            Get
                Return mID
            End Get
            Set(ByVal value As String)
                mID = value
            End Set
        End Property

        Private mName As String
        Public Property Name() As String
            Get
                Return mName
            End Get
            Set(ByVal value As String)
                mName = value
            End Set
        End Property
    End Class

然后這部分：

ComboBox3.DataSource = GetBillingMonthsGrouped()
ComboBox3.DisplayMember = "Name"
ComboBox3.ValueMember = "ID"
ComboBox3.SelectedIndex = 0

我需要使用什么代碼將ComboBox3的選定值更改為當前月份

我嘗試使用：

ComboBox3.SelectedValue = DateTime.Now.ToString("MM")

但這不會更改所選的值。 我需要將值作為月份號並將顯示作為月份名稱

Answer 1

希望comboBox已經具有月份，您需要將當前月份設置為選中狀態。 那么在這種情況下，您可以使用以下代碼將current month選擇為所選月份

  ComboBox1.SelectedIndex = Now.Month

如果您只想顯示一個月，則可以使用以下代碼：

  ComboBox1.SelectedText = DateTime.Today.ToString("MMMM")