Question

我正在开发一个VB类的项目，我将一个访问数据库连接到VB项目，并将数据分开显示。我很难找到能够完成这项任务的特定行代码。

我所要做的就是将一列年龄分成3组，然后将这些信息分成3个文本行。

我知道循环非常好但我找不到确切的代码措辞去数据库并解析出来......

到目前为止，这是所有代码......

Public Class frmSportsLeague

Private Sub TeamBindingNavigatorSaveItem_Click(sender As Object, e As EventArgs) Handles TeamBindingNavigatorSaveItem.Click
    Me.Validate()
    Me.TeamBindingSource.EndEdit()
    Me.TableAdapterManager.UpdateAll(Me.LittleLeagueDataSet)

End Sub

Private Sub frmSportsLeague_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    'TODO: This line of code loads data into the 'LittleLeagueDataSet.Team' table. You can move, or remove it, as needed.
    Try
        TeamTableAdapter.Fill(Me.LittleLeagueDataSet.Team)
    Catch
        MsgBox("The database is not there!!!")
    End Try

End Sub

Private Sub btnAge_Click(sender As Object, e As EventArgs) Handles btnAge.Click

    'strSQL is an SQL statement that selects and imports all fields from the gardener database
    Dim strsql As String = "SELECT * FROM Team"
    Dim strPath As String = "Provider=Microsoft.ACE.OLEDB.12.0 ;" & "Data Source = C:\Windows\Temp\LittleLeague.accdb"
    Dim odaLittleLeague As New OleDb.OleDbDataAdapter(strsql, strPath)

    Dim datPlayers As New DataTable
    Dim intCount As Integer
    Dim intTwelve As Integer = 0
    Dim intThirteen As Integer = 0
    Dim intFourteen As Integer = 0
    Dim decAllAges As Decimal = 0D
    Dim decAverage As Decimal = 0D
    Dim intPlayers As Integer


    btnAge.Visible = False

    'The datCost DataTable gets the table data imported 
    odaLittleLeague.Fill(datPlayers)
    'The connection to the database is closed
    odaLittleLeague.Dispose()

    For intCount = 0 To datPlayers.Rows.Count - 1
        decAllAges += Convert.ToDecimal(datPlayers.Rows(intCount)("Age"))

    Next

        intPlayers = datPlayers.Rows.Count
        decAverage = decAllAges / intPlayers

        lblTwelve.Visible = True
        lblTwelve.Text = "The number of 12 year old players is: " & intTwelve.ToString()
        lblThirteen.Visible = True
        lblThirteen.Text = "The number of 13 year old players is: " & intThirteen.ToString()
        lblFourteen.Visible = True
        lblFourteen.Text = "The number of 14 year old players is: " & intFourteen.ToString()
        lblAverage.Visible = True
        lblAverage.Text = "The average age of all the players is: " & decAverage.ToString("F2")

End Sub

结束班

Answer 1

假设年龄在数据库中存储为文本（没有数据库规范，但我可以看到您的代码中有一个转换为十进制），在代码中添加“select case”应该执行特技。修改后的循环：

For intCount = 0 To datPlayers.Rows.Count - 1
    decAllAges += Convert.ToDecimal(datPlayers.Rows(intCount)("Age"))
    Select Case (datPlayers.Rows(intCount)("Age"))
        Case "12"
            intTwelve += 1
        Case "13"
            intThirteen += 1
        Case "14"
            intFourteen += 1
        Case Else
            MsgBox("Error: Age not in range 12-14!")
    End Select
Next

从访问VB2013获取特定列数据

1 个答案: