Dim conn As New SqlConnection("server=.;database=login;integrated security=sspi")
Dim comm As New SqlCommand
Dim ds As New DataSet
Dim da As New SqlDataAdapter
Dim user, password As String
user = ComboBox1.Text
password = TextBox1.Text
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
comm.Connection = conn
comm.CommandType = CommandType.Text
comm.CommandText = "select * from Login where username = '" & user & "' and password = '" & password & "'"
da.SelectCommand = comm
If comm.CommandType <> 0 Then
MessageBox.Show("GO!")
Else
MessageBox.Show("NO!")
ComboBox1.Text = ""
TextBox1.Text = ""
ComboBox1.Focus()
Me.Focus()
End If
conn.Close()
这是button里的代码，为什么无论密码对错都是“GO”啊？
大家指点一下！谢谢~

那应该怎么改啊？

comm.Connection = conn
comm.CommandType = CommandType.Text
comm.CommandText = "select * from Login where username = '" & user & "' and password = '" & password & "'"
da.SelectCommand = comm
'da.Fill(ds)
If comm.ExecuteNonQuery > 0 Then
MessageBox.Show("GO!")
Else
MessageBox.Show("NO!")
ComboBox1.Text = ""
TextBox1.Text = ""
ComboBox1.Focus()
Me.Focus()
End If
conn.Close()

改了以后就只显示NO了无论输什么密码~

还是不行！这是全部代码：
Dim user, password As String
user = ComboBox1.Text.Trim
password = TextBox1.Text.Trim
If conn.State = ConnectionState.Closed Then
conn.Open()
End If
comm.Connection = conn
comm.CommandType = CommandType.Text
comm.CommandText = "select * from Login where username = '" & user & "' and password = '" & password & "'"
da.SelectCommand = comm
da.Fill(ds)
If comm.ExecuteNonQuery > 0 Then
MessageBox.Show("GO!")
Else
MessageBox.Show("NO!")
ComboBox1.Text = ""
TextBox1.Text = ""
ComboBox1.Focus()
Me.Focus()
End If
conn.Close()