Question

我只是想问这个问题（标题）。我有一个名为PR_rating的列，我需要根据学生ID向TextBoxes显示值，这样一个学生ID =很多PR_rating。我的问题是我不知道该怎么做。 TextBox只显示一个TextBox中的所有值。抱歉我的英语不好。

Imports System.Data.OleDb

Public Class adminEval
    Dim provider As String
    Dim dataFile As String
    Dim connString As String
    Public myConnection As OleDbConnection = New OleDbConnection
    Public dr As OleDbDataReader

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        provider = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source ="
        dataFile = "C:\Users\Billy\Desktop\TH\exampleData.accdb"
        connString = provider & dataFile
        myConnection.ConnectionString = connString
    End Sub

    Private Sub btnSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSearch.Click
        myConnection.Open()
        Dim str As String
        str = "SELECT * FROM [Transaction] WHERE (Stud_no ='" & txtstudnum.Text & "')"
        Dim cmd As OleDbCommand = New OleDbCommand(str, myConnection)
        dr = cmd.ExecuteReader
        While dr.Read()
            txteng11.Text &= dr(7).ToString() & Environment.NewLine

Answer 1

使用文本框以外的其他内容来存储此数据可能更好。我更喜欢将代码放入datatable，然后将其加载到datagridview。

以下是使用您的代码的示例：

'new variables added for this example
dim dataAdapter as New OldDbDataAdapter
dim dataTable as New DataTable
dim dataGrid as New DataGridView

Private Sub btnSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSearch.Click

    myConnection.Open()

    Dim str as String
    str = "SELECT * FROM [Transaction] WHERE (Stud_no=@studentNum)"
    Dim cmd as OleDbCommand = New OleDbCommand(str, my connection)
    'Use parameters to safely fill the SQL string
    cmd.Parameters.Add("@studentNum",OleDbType.String).value = txtstudnum.Text

    dataAdapter.SelectCommand = cmd
    'fill the dataTable using the dataAdapter, which has been executed above
    dataAdapter.Fill(dataTable)
    'Use the dataTable as the dataGrid's source to add the data into it
    dataGrid.DataSource = dataTable

    myConnection.Close()        

End Sub

上面我也使用了OleDbCommand parameters。这允许您安全地填充SQL字符串以供执行。

使用Data Adapter，您可以从命令中将数据放入此中，并使用此数据填充dataTable。填好表后，您可以将表格dataGridView填入表单（从工具箱插入表单），将表格设置为DataSource。

如果这不适合您的需求，我很抱歉，我通常会使用MySQL，所以OleDB对我来说很新，但语法相似。

显示从单个字段到多个文本框的不同数据（VB 2010 / MS Acess）

1 个答案: