请问数据库怎么更新不了？

代码如下:

Imports System.Data.SqlClient
Public Class FillDS
Public SqlAdp As New SqlDataAdapter
Public Sqlconn As SqlConnection
Public Function F_FillDS(ByVal strSelect As String) As DataSet
Dim ConnString As String = "....连接到数据库的string...."
Sqlconn = New SqlConnection(ConnString)
Dim DS As New DataSet
SqlAdp.SelectCommand = New SqlCommand(strSelect, Sqlconn)
Sqlconn.Open()
DS.Clear()
SqlAdp.Fill(DS)
Sqlconn.Close()
Return DS
End Function
Public Function F_UpdateDB(ByVal dsName As DataSet)
Sqlconn.Open()
SqlAdp.Update(dsName)
Sqlconn.Close()
End Function
End Class
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在主窗体中：

Public c1 As New FillDS
Public ds1 As DataSet
ds1 = c1.F_FillDS("....select语句....")
......
与窗体控件绑定的代码
......
点击保存按钮后：

me.BindingContext(ds1, ds1.Tables(0).TableName).EndCurrentEdit()
ds1.AcceptChanges()
c1.F_UpdateDB(ds1)



老师们请看看这么做为什么不能更新数据库？哪里不对？运行没有任何错误提示

另外还有一个问题,没有分了，两个问题一起问，呵呵

Dim ConnString As String = ""....连接到数据库的string...."
Dim SqlConn As New SqlConnection(ConnString)
Dim dReader As SqlDataReader
Dim SqlCmd As New SqlCommand
SqlCmd.CommandText = "select * from tb1 where username = @name"
SqlCmd.CommandType = CommandType.Text
SqlCmd.Connection = SqlConn
SqlCmd.Parameters("name").Value = txtname.text
'或者SqlCmd.Parameters(0).Value = txtname.text
SqlConn.Open()
dReader = SqlCmd.ExecuteReader()
Sqlconn.close
运行后提示没有这个参数，请问是怎么回事？用"?"代替"@name"也不行。