如何更快地加載 vb.net Combobox

Question

我是 Vb.net 的新手，我使用此代碼從 Mysql 數據庫加載 Combobox。 效果很好，但速度很慢

有沒有辦法在一個查詢中執行所有這些並加載所有組合框或另一種更快地執行此任務的方法？

    AbrirDB()
    comandomysql.CommandText = "select distinct TblMarcas.marca from TblMarcas order by marca"
    Try
        Lector = comandomysql.ExecuteReader
        Lector.Read()
        .cbom.Properties.Items.Clear()
        If Lector.HasRows Then
            .cbom.Properties.Items.Add(Lector.Item("marca"))
            Do While Lector.Read
                .cbom.Properties.Items.Add(Lector.Item("marca"))
            Loop
        Else
        End If
    Catch ex As Exception
        DevExpress.XtraEditors.XtraMessageBox.Show(Err.Number & Err.Description)
        If conexion.State = ConnectionState.Open Then conexion.Close()
    End Try
    CerrarDb()




    'CARGO  Categorias a treelist
    AbrirDB()
    comandomysql.CommandText = "select distinct TblCategorias.categoria from TblCategorias order by categoria ASC"
    Try
        Lector = comandomysql.ExecuteReader
        Lector.Read()
        .cboc.Properties.Items.Clear()
        If Lector.HasRows Then
            .cboc.Properties.Items.Add(Lector.Item("categoria"))
            Do While Lector.Read
                .cbocategoria.Properties.Items.Add(Lector.Item("categoria"))
            Loop
        Else

        End If

    Catch ex As Exception
        DevExpress.XtraEditors.XtraMessageBox.Show(Err.Number & Err.Description)
        If conexion.State = ConnectionState.Open Then conexion.Close()
    End Try
    CerrarDb()


    'CARGO Subcategorias
    AbrirDB()
    comandomysql.CommandText = "select distinct TblSubcategorias.subcategoria from TblSubcategorias order by subcategoria ASC"
    Try
        Lector = comandomysql.ExecuteReader
        Lector.Read()
        .cbos.Properties.Items.Clear()
        If Lector.HasRows Then
            .cbos.Properties.Items.Add(Lector.Item("subcategoria"))
            Do While Lector.Read
                .cbos.Properties.Items.Add(Lector.Item("subcategoria"))
            Loop

        End If

    Catch ex As Exception
        DevExpress.XtraEditors.XtraMessageBox.Show(Err.Number & Err.Description)
        If conexion.State = ConnectionState.Open Then conexion.Close()
    End Try
    CerrarDb()

任何幫助，將不勝感激。

Answer 1

嘗試：
myCombo.SuspendLayout（）
昏暗的表作為新的DataTable（）
table.Load（MyDataReader）
myCombo.DataSource =表
myCombo.DisplayMember = “列1”
myCombo.ResumeLayout（）

Answer 2

           Dim ds As DataTable = yourtable
           Dim arr As Object() = (From dc In ds.AsEnumerable Select dc(0)).ToArray
           combo.Items.AddRange(arr)