菜鸟咨询下～～ 如何在VB里 执行SQL 语句～

就 下 问下 代码 怎么 写   的  我执行的  都报错  估计 写的 都不对  

    Dim LeafSqlConnection As SqlConnection  
    Dim LeafSqlCommand As SqlCommand
    Dim LeafSqlDataAdapter As SqlDataAdapter
    Dim LeafData As DataTable              

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
     
        'LeafSqlConnection = New SqlConnection("Initial Catalog=LENOVO-C4F87463 ;User ID=sa;PWD=123456")  
        LeafSqlCommand = New SqlCommand("select  * from  vw_xsdtl"）
        LeafSqlDataAdapter = New SqlDataAdapter
         = CommandType.Text
        LeafSqlDataAdapter.SelectCommand = LeafSqlCommand
        LeafData = New DataTable
        LeafSqlDataAdapter.Fill(LeafData)
        DataGridView1.DataSource = LeafData
    End Sub
End Class

我常用的写法，用Adodc控件，不用设置直接粘贴代码，因英语水平差，基本用中文写
Private Sub Form_Activate()
  S = App.Path & "\LawStatute.mdb"   '数据库名称LawStatute，放在对应的编写程序夹内，为Access数据库
  Adodc1.ConnectionString = "Provider=Microsoft.Jet.OLEDB.4.0;" & _
"Data Source =" + Chr(34) + S + Chr(34) & ";Jet OLEDB:Database Password=chen3523;"  '打开有密码数据库，密码为“chen3523”
      Dim SQL As String
      SQL = "SELECT * FROM 文件表 "
       = adCmdunknow                'SQL必须用此句，否则会显示FROM子句出错
      Adodc1.RecordSource = SQL
      Adodc1.Refresh
        Set DataGrid1.DataSource = Adodc1        
End Sub

Private Sub Command1_Click()
      Dim SQL As String      
     my = Chr(34) + "%" + Trim$(Text1.Text) + "%" + Chr(34)
      SQL = "SELECT * FROM 文件表  where 文件名称 like " & my & " order by 发文时间 desc"
       = adCmdunknow                'SQL必须用此句，否则会显示FROM子句出错
      Adodc1.RecordSource = SQL
      Adodc1.Refresh
        Set DataGrid1.DataSource = Adodc1        
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

绝对是 的代码，
看了半天，还以为是 全部是用类写的。仔细看函数名，才发现是 的代码。
按照我的理解，数据库，先要打开。没发现，也许是你注释掉的那行移到全局进行操作。
然后 使用这个连接来打开数据库。
看你后面的代码，无一涉及到 数据连接的使用。

这是我以前写的一个基于VB的SQL条件查询。你参考一下。
Private Sub Button5_Click(sender As System.Object, e As System.EventArgs) Handles Button5.Click
        Dim con As New SqlConnection
        Dim cmd As New SqlCommand
        Dim dr As SqlDataReader
        Dim s As String
        Dim wendu As String
        Dim home As room
        Dim time As String
        wendu = TextBox6.Text.ToString
        Try
            con.ConnectionString = "server = USER-20150216TC\ZHOU;database = ZHOU;user id = sa;password=zhou;"
            s = "select room1,room2,co,red, tim from Table_1 " + "where room1>=" + "'" + wendu.ToString + "'" + "or room2>=" + "'" + wendu.ToString + "'"
            cmd.Connection = con
             = CommandType.Text
             = s
            con.Open()
            dr = cmd.ExecuteReader
            Do While dr.Read()
                home.wendu1 = dr.GetString(0)
                home.wendu2 = dr.GetString(1)
                home.co = dr.GetString(2)
                home.red = dr.GetString(3)
                time = dr.GetString(4)
                DataGridView1.Rows.Add(home.wendu1, home.wendu2, home.co, home.red, time)
            Loop
            con.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try
    End Sub