Question

我正在尝试让我的系统将组合框值插入到我的访问数据库中。每当我尝试单击“添加”按钮时，我总会得到这个很长的错误，而且我感觉这是因为我的INSERT语句。这是我表格的全部代码。任何帮助将不胜感激！谢谢

Imports System.Data.OleDb

Public Class AdmMain


    Sub fillcombo()
        strsql = " select yrgr from yearandgrade"
        Dim acscmd As New OleDb.OleDbCommand
        acscmd.CommandText = strsql
        acscmd.Connection = acsconn
        acsdr = acscmd.ExecuteReader

        While (acsdr.Read())
            cboyr.Items.Add(acsdr("yrgr"))
        End While
        acscmd.Dispose()
        acsdr.Close()
    End Sub

    Sub comb2()
        strsql = " select sections from sectio"
        Dim acscmd As New OleDb.OleDbCommand
        acscmd.CommandText = strsql
        acscmd.Connection = acsconn
        acsdr = acscmd.ExecuteReader

        While (acsdr.Read())
            cbosec.Items.Add(acsdr("sections"))
        End While
        acscmd.Dispose()
        acsdr.Close()
    End Sub

    Private Sub LinkLabel1_LinkClicked(sender As System.Object, e As System.Windows.Forms.LinkLabelLinkClickedEventArgs) Handles LinkLabel1.LinkClicked
        If MessageBox.Show("Are you sure you want to logout?", "Logout", MessageBoxButtons.YesNo, MessageBoxIcon.Question) = Windows.Forms.DialogResult.Yes Then
            MessageBox.Show("You have successfully logged out of VCM's Library Information System!", "Logout Confirmed")
            Me.Close()
            LoginUser.Show()
        End If
    End Sub

    Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
        Me.txtFName.Text = ""
        Me.txtMName.Text = ""
        Me.txtLName.Text = ""
        Me.cboyr.Text = ""
        Me.cbosec.Text = ""
        Me.txtFName.Focus()
    End Sub

    Private Sub AdmMain_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
        Module1.connect()
        Me.fillcombo()
        Me.comb2()

    End Sub


    Private Sub btnAdd_Click(sender As System.Object, e As System.EventArgs) Handles btnAdd.Click
        Dim rbdtext As String = cboyr.SelectedItem.ToString
        Dim uno As String = cbosec.SelectedItem.ToString
        Try
            Using conn = New System.Data.OleDb.OleDbConnection()
                conn.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;" & _
                                        "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Thesis\Thesis\Database1.accdb"
                conn.Open()
                Dim sqlquery As String = "INSERT INTO students (StudentID, FirstName,MiddleName,LastName,Yr, Section) " & _
                                        "VALUES (@studid, @fname,@mname,@lname,@yr, @sec)"
                Dim SqlCommand As New System.Data.OleDb.OleDbCommand
                SqlCommand.Parameters.AddWithValue("@studid", TxtID.Text)
                SqlCommand.Parameters.AddWithValue("@fname", txtFName.Text)
                SqlCommand.Parameters.AddWithValue("@mname", txtMName.Text)
                SqlCommand.Parameters.AddWithValue("@lname", txtLName.Text)
                SqlCommand.Parameters.AddWithValue("@yr", rbdtext)
                SqlCommand.Parameters.AddWithValue("@sec", uno)
                SqlCommand.Connection = conn

                Dim sqlRead As System.Data.OleDb.OleDbDataReader = SqlCommand.ExecuteReader()

                MsgBox("One record successfully added!", "Added!")

            End Using
        Catch ex As Exception
            MsgBox(ex.ToString)
        End Try

    End Sub

继续显示btw的错误！ http://i.imgur.com/DgjiWqm.png

Answer 1

您似乎永远不会在SqlCommand方法中为btnAdd_Click分配select语句。尝试添加SqlCommand.CommandText = sqlquery。

Answer 2

您需要以这种方式更改查询

Private Sub btnAdd_Click(sender As System.Object, e As System.EventArgs) Handles btnAdd.Click
    Dim rbdtext As String = cboyr.SelectedItem.ToString
    Dim uno As String = cbosec.SelectedItem.ToString

    Try
        Dim cnString = = "Provider=Microsoft.ACE.OLEDB.12.0;" & _ 
                         "Data Source=C:\Thesis\Thesis\Database1.accdb"
        Dim sqlquery As String = "INSERT INTO students " & _
            "(StudentID, FirstName,MiddleName,LastName,Yr, [Section]) " & _
            "VALUES (@studid, @fname,@mname,@lname,@yr, @sec)"

        ' Use this form to initialize both connection and command to 
        ' avoid forgetting to set the appropriate properties....

        Using conn = New System.Data.OleDb.OleDbConnection(cnString)
        Using cmd = New System.Data.OleDb.OleDbCommand(sqlQuery, conn)

            conn.Open()
            cmd.Parameters.AddWithValue("@studid", TxtID.Text)
            cmd.Parameters.AddWithValue("@fname", txtFName.Text)
            cmd.Parameters.AddWithValue("@mname", txtMName.Text)
            cmd.Parameters.AddWithValue("@lname", txtLName.Text)
            cmd.Parameters.AddWithValue("@yr", rbdtext)
            cmd.Parameters.AddWithValue("@sec", uno)

            Dim rowsInserted = cmd.ExecuteNonQuery()
            if rowsInserted > 0 Then
                MessageBox.Show("One record successfully added!", "Added!")
            else
                MessageBox.Show("Failure to add new record!", "Failure!")
            End if
        End Using
        End Using
    Catch ex As Exception
        MessageBox.Show("Error: " & ex.Message)
    End Try

我已经更改了OleDbCommand对象的名称，以避免与SqlClient命名空间中使用的类SqlCommand产生不必要的混淆（不是严格必要但在阅读代码时却令人困惑）。然后我使用OleDbCommand构造函数来获取命令文本和命令使用的连接。这样可以避免忘记设置这些基本属性，最后 SECTION 是reserved keyword for MS-Access，因此，在查询文本中使用时，需要将其封装在方括号之间，否则会得到{{1} }

插入组合框值？

2 个答案: