VB.NET中sqladapter.fill抛现异常.提示 列无效．

VB.NET中sqladapter.fill抛现异常.提示 列无效．我写了一段小程序，发现在程序运行过程中，有异常错误，主要是按照几个字段来查询ＳＱＬ数据库，combobox里包括字段：编号，姓名，国籍，业绩，加入时间．．．相对应在ＳＱＬ中是bh,xm,gj,yj,joindata．．．．各个字段的类型都设置为varchar类型，当使用＂姓名＂的时候就报错．说列名无效.其中数据库表名为sales
原代码如下


Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim id As String = TextBox1.Text
Dim di As String = ComboBox1.Text
Dim constring As String = "Data Source=6FFF157A3A3E49C;Initial Catalog=lzgdb;Integrated Security=True " '定义连接字符串
Dim sqlcon As New SqlClient.SqlConnection(constring) '定义连接
Dim r1 As String = "select * from sales where bh= " & id.ToString '定义combobox中选项的具体意义
Dim r2 As String = "select * from sales where xm= " & id.ToString
Dim r3 As String = "select * from sales where gj= " & id.ToString
Dim r4 As String = "select * from sales where yj= " & id.ToString
Dim r5 As String = "select * from sales where joindate= " & id.ToString
If di = " " Then
MessageBox.Show( "please change item! ")
Else
If id = " " Then