Question

studentrecords table。，。，包含IDNumber，LastName，Course，Firstname

我将使用IDNumber登录我的系统，一旦我转到mainform，我就会使用IDNumber作为主键，在主窗体中显示LASTname和当然2个文本框。，我的代码错误

Dim con As New OleDbConnection Dim cmd As New OleDbCommand

  Dim da As New OleDbDataAdapter

  Dim dt As New DataTable

  Dim sSQL As String = String.Empty

  'get connection string declared in the Module1.vb and assing it to conn variable

  con = New OleDbConnection(Get_Constring)

  con.Open()

  cmd.Connection = con

  cmd.CommandType = CommandType.Text
  sSQL = "SELECT  LastName FROM studentsrecords where IDNumber like '%" & studentslogin.[txtIDNumber].Text & "%' order by ID desc"

  cmd.CommandText = sSQL

  da.SelectCommand = cmd

  da.Fill(dt)

  'evalutionrate.[lbllogin].Text = studentslogin.[txtIDNumber].Text

  evalutionrate.[lbllogin].Text = sSQL

  evalutionrate.Show()

Answer 1

这里：只需创建一个新标签“label = lbllogin并将其隐藏”在welcome或mainform中，因为它将成为读取数据库的关键。

Private Sub Mainform_Load(sender As Object, e As EventArgs) Handles MyBase.Load
 If conn.State = ConnectionState.Closed Then
        conn.Open()
    End If
    lbllogin.Text = Login.studentslogin.Text
    Dim sqlquery As String = "select * from studentsrecords where IDNumber =@ID"
    Dim sqlcommad As New OleDbCommand
    Dim sqlread As OleDbDataReader
    sqlcommad.CommandText = sqlquery
    sqlcommad.Connection = conn
    sqlcommad.Parameters.AddWithValue("@ID", lbllogin.Text)
    sqlcommad.ExecuteNonQuery()
    sqlread = sqlcommad.ExecuteReader
    Try
        If (sqlread.Read()) Then
            textbox1.Text = sqlread("LASTname ")      
            textbox2.Text = sqlread("course ")

        End If
    Catch ex As Exception

    End Try
    conn.Close()
End Sub

如果这个答案有用，请不要忘记投票。

将数据加载到我的mainform

1 个答案: