asp.net用户注册时的验证

////验证用户名是否与注册数据库中的重名！！！

Private Sub check_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles check.Click

Dim myConnection As OleDbConnection

Dim myCommand As OleDbCommand

Dim dbname As String

dbname = Server.MapPath("db1.mdb")

myConnection = New OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA Source=C:\Documents and Settings\Administrator\My Documents\Visual Studio Projects\WebApplication1 (2)\database\db1.mdb")数据库所在的目录

If userid.Text = "" Then

Label5.Text = "error!!you must complete it"

Else

Dim checklogin As String

checklogin = "select * from users "

Dim cmd As New OleDbCommand(checklogin, myConnection)

Dim reader As OleDbDataReader

Try

myConnection.Open()

reader = cmd.ExecuteReader()

reader.Read()

If userid.Text = reader("userid") Then

Label5.Text = "the userid had been used"

Else

Label5.Text = "this userid can use"

End If

Catch err As Exception

Trace.Write(err.Message)

Label5.Text = "checked error"

Finally

If (Not myConnection Is Nothing) Then

myConnection.Close()

End If

End Try

End If

End Sub

////用户注册

Private Sub regist_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles regist.Click

Dim myConnection As OleDbConnection

Dim myCommand As OleDbCommand

Dim dbname As String

dbname = Server.MapPath("db1.mdb")

myConnection = New OleDbConnection("PROVIDER=Microsoft.Jet.OLEDB.4.0;DATA Source=C:\Documents and Settings\Administrator\My Documents\Visual Studio Projects\WebApplication1 (2)\database\db1.mdb")

Dim strinsert As String

strinsert = "insert into users("

strinsert &= "u_id,u_password)"

strinsert &= "values('"

strinsert &= userid.Text & "','"

strinsert &= password.Text & "')"

Dim cmd As New OleDbCommand(strinsert, myConnection)

Dim added As Integer

Try

myConnection.Open()

added = cmd.ExecuteNonQuery

If added > 0 Then

Label5.Text = "your information is added"

Response.Redirect("home.aspx")

End If

Catch err As Exception

Trace.Write(err.Message)

Label5.Text = "added error"

Finally

If (Not myConnection Is Nothing) Then

myConnection.Close()

End If

End Try

End Sub

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