Vb.net SQL中的调试错误

大家好：有谁能帮我解决这个错误吗？谢谢 错误1未为类型“String”和“System.Windows.Forms.TextBox”定义运算符“&”。C:\Users\kathy\AppData\Local\Temporary Projects\WindowsApplication1\Form1.vb 20 WindowsApplication1

导入System.Data.OleDb 公开课表格1 公共连接为String=Provider=Microsoft.ACE.OLEDB.12.0；数据源=C:\Users\kathy\Desktop\generalledger.accdb 公共连接作为新的OLEDB连接

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    conn.ConnectionString = connection
    If conn.State = ConnectionState.Closed Then
        conn.Open()
        MsgBox("Open")
    Else
        MsgBox("Closed")

    End If

End Sub

Private Sub BtnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnAdd.Click
    Dim sqlQuery As String
    sqlQuery = "insert into voucher(VoucherName, Account_Code, Amount) values ('" & TxtVoucher & "', " & TxtAmount & ", '" & TxtAccount & "')"
    Dim sqlcommand As New OleDbCommand
    With sqlcommand
        .CommandText = sqlQuery
        .Connection = conn
        .ExecuteNonQuery()
    End With
    MsgBox("Save")

End Sub

结束类

只需在文本框中添加.Text即可

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        conn.ConnectionString = connection
        If conn.State = ConnectionState.Closed Then
            conn.Open()
            MsgBox("Open")
        Else
            MsgBox("Closed")

        End If

    End Sub

    Private Sub BtnAdd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnAdd.Click
 conn.Open()
        Dim sqlQuery As String

        sqlQuery = "insert into voucher(VoucherName, Account_Code, Amount) values ('"+ TxtVoucher + "', " + TxtAmount + ", '" + TxtAccount + "')"
        Dim sqlcommand As New OleDbCommand
        With sqlcommand
            .CommandText = sqlQuery
            .Connection = conn
            .ExecuteNonQuery()
 conn.Close()
        End With
        MsgBox("Save")

    End Sub

 sqlQuery = "insert into voucher(VoucherName, Account_Code, Amount) values ('" & TxtVoucher & "', " & TxtAmount & ", '" & TxtAccount & "')"

到

 sqlQuery = "insert into voucher(VoucherName, Account_Code, Amount) values ('" & TxtVoucher.Text() & "', " & TxtAmount.Text() & ", '" & TxtAccount.Text() & "')"