VB.NET

Deja Vu...

Kyle — Wed, 27 Jun 2007 10:07:23 GMT

Does this ever happen to you?

I was just a few minutes ago, working through a problem with sorting custom classes. I know that I did this before, but couldn't remember what I did. So, I popped a few search terms into Google, and came across a potential solution. Then I looked a little more carefully at the blog, and realized that the solution I found was mine... A year and a half ago...

http://geekswithblogs.net/kyle/archive/2006/01/12/65680.aspx

SQL Reporting Services

Kyle — Thu, 26 Apr 2007 12:11:30 GMT

50% of my job is Web Development. The other 50% is managing a 2GB SQL database and web app (with about 1500 users). Part of that 50% is writing SQL Reporting reports. Up until the other day, I was having my users log into the web interface of S/RS and get their reports that way. I was talking to some other developers who use the same system, and they said that you can Proxy into reports using code.

I dug into this a little bit, and in about 2 hours, whipped up a little VB.NET page that did the trick. All it needed was a ReportViewer control, a small helper class, and about 3 more lines of code. Of course, I spruced it up a little bit, entering parameters based on Query String variables, etc. But, here's the gist of what I had put together (with a lot of online help.)

1   Imports System.Collections
2   Imports System.ComponentModel
3   Imports System.Data
4   Imports System.Drawing
5   Imports System.Web
6   Imports System.Web.SessionState
7   Imports System.Web.UI
8   Imports System.Web.UI.WebControls
9   Imports System.Web.UI.HtmlControls
10  Imports Microsoft.Web.UI.WebControls
11  Imports System.Net
12  Imports System.Security.Principal
13  Imports Microsoft.Reporting.WebForms
14
15
16  Partial Class _Default
17      Inherits System.Web.UI.Page
18      Public ReadOnly Property ReportServer() As String
19          Get
20              Return "http://reportserver/reportserver"
21          End Get
22      End Property
23
24      Public ReadOnly Property ReportPath()
25          Get
26              Return "/Proxy"
27          End Get
28      End Property
29
30      Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
31
32          If Not ispostback Then
33              ReportViewer1.ServerReport.ReportServerCredentials = _
34                          New MyReportServerCredentials()
35              ReportViewer1.ServerReport.ReportPath = ReportPath & CStr(Request.QueryString("rpt")).Replace("%20", " ")
36              Dim p As New System.Collections.Generic.List(Of Microsoft.Reporting.WebForms.ReportParameter)
37
38              'Check to see if the report has a requirement for a person ID.
39              Dim d As Microsoft.Reporting.WebForms.ReportParameterInfoCollection = ReportViewer1.ServerReport.GetParameters()
40              Dim di As Microsoft.Reporting.WebForms.ReportParameterInfo
41              For Each di In d
42                  If di.Name.ToLower = "calendarid" Then
43                      If Not IsNothing(Request.QueryString("CalendarId")) Then
44                          p.Add(New Microsoft.Reporting.WebForms.ReportParameter("CalendarId", Request.QueryString("CalendarId")))
45                      End If
46                  End If
47              Next
48
49              ReportViewer1.ServerReport.SetParameters(p)
50              ReportViewer1.PromptAreaCollapsed = False
51          Else
52              ReportViewer1.PromptAreaCollapsed = True
53          End If
54
55      End Sub
56  End Class
57
58  <Serializable()> _
59  Public NotInheritable Class MyReportServerCredentials
60      Implements IReportServerCredentials
61
62      Public ReadOnly Property ImpersonationUser() As WindowsIdentity _
63              Implements IReportServerCredentials.ImpersonationUser
64          Get
65
66              'Use the default windows user.  Credentials will be
67              'provided by the NetworkCredentials property.
68              Return Nothing
69
70          End Get
71      End Property
72
73      Public ReadOnly Property NetworkCredentials() As ICredentials _
74              Implements IReportServerCredentials.NetworkCredentials
75          Get
76
77              'Read the user information from the web.config file.
78              'By reading the information on demand instead of storing
79              'it, the credentials will not be stored in session,
80              'reducing the vulnerable surface area to the web.config
81              'file, which can be secured with an ACL.
82
83              'User name
84              Dim userName As String = _
85                  ConfigurationManager.AppSettings("MyReportViewerUser")
86
87              If (String.IsNullOrEmpty(userName)) Then
88                  Throw New Exception("Missing user name from web.config file")
89              End If
90
91              'Password
92              Dim password As String = _
93                  ConfigurationManager.AppSettings("MyReportViewerPassword")
94
95              If (String.IsNullOrEmpty(password)) Then
96                  Throw New Exception("Missing password from web.config file")
97              End If
98
99              'Domain
100              Dim domain As String = _
101                  ConfigurationManager.AppSettings("MyReportViewerDomain")
102
103              If (String.IsNullOrEmpty(domain)) Then
104                  Throw New Exception("Missing domain from web.config file")
105              End If
106
107              Return New NetworkCredential(userName, password, domain)
108
109          End Get
110      End Property
111
112      Public Function GetFormsCredentials(ByRef authCookie As Cookie, _
113                                          ByRef userName As String, _
114                                          ByRef password As String, _
115                                          ByRef authority As String) _
116                                          As Boolean _
117              Implements IReportServerCredentials.GetFormsCredentials
118
119          authCookie = Nothing
120          userName = Nothing
121          password = Nothing
122          authority = Nothing
123
124          'Not using form credentials
125          Return False
126
127      End Function
128
129  End Class

Ajax.NET and DataBound Server Controls

Kyle — Wed, 22 Feb 2006 14:28:00 GMT

Over on the AjaxPro Google Group, a user asked a question about databinding a repeater using Ajax. The response has always been "A repeater (or any other server control) is rendered on the server, and then passed back to the client as HTML." One of the purposes of Ajax is to reduce the amount of bytes being sent back and forth between server and client on non-initial load functions.

In this post, the usual answers were given. Loop through the dataset with JavaScript, then display the results. This makes sense to me.

Then I got thinking. For those who don't want the hassle of looping through datasets to build tables, but are more comfortable with server side databinding, there is a way...

***SERVER SIDE***

<AjaxPro.AjaxMethod()> _
    Public Function getDG() As String

        Dim ds As New DataSet
        'Fill the DS however you want...

        Dim DataGrid1 As New DataGrid
        DataGrid1.DataSource = ds
        DataGrid1.DataBind()

        Dim SB As New System.Text.StringBuilder
        Dim SW As New System.io.StringWriter(SB)
        Dim htmlTW As New HtmlTextWriter(SW)

        DataGrid1.RenderControl(htmlTW)

        Return SB.ToString

    End Function

***CLIENT SIDE***

<div id="DataGrid1"></div>
<a href="javascript:void(0);" onclick="test();">Here</a>
<script>
    function test()
        {
        ServerSideRenderControl.WebForm1.getDG(getDGCallback);
        }
    function getDGCallback(res)
        {
        document.getElementById("DataGrid1").innerHTML = res.value;
        }
</script>

This method (though large) allows you to databind a data-aware control on the server side, and then pass it out to the client through Ajax. I haven't dealt with server-side templates (for repeaters)... You're on your own for that. Enjoy!

HttpHandler for Image Resizing

Kyle — Fri, 17 Feb 2006 17:48:00 GMT

Is using an HttpHandler for image resizing the best way to go?

If I have a site that gets a ton of hits, will the server be constantly pegged resizing all those images?

Anyone have any experience, advice to offer a HttpHandler newbie?

Cache Crazy

Kyle — Sun, 12 Feb 2006 01:24:00 GMT

I know it's probably not "best design" to go Cache Crazy, and cache everything under the sun. But, for a lot of things it makes sense. For data that changes often, it may not be worth it. It's possible that every time you cache something that changes often, you'll just be hitting the database again to cache the new data. I say, if you've got the memory, go for it.

Second comment. It's important to remember all the ways in which you're caching the data. For example, I'm not only caching individual rows from the database which are represented as classes, but I'm caching the collections of the rows as well. That way, when there's a search, etc, the database isn't being so stressed out. I just have to remember where (and when) I'm caching all these objects. So, when one element in the collection changes, I can refresh it.

Multiple Content Place Holders on Single Master Page

Kyle — Tue, 31 Jan 2006 14:15:00 GMT

As it turns out, it is possible to have multiple content areas on a single master page.

Master Page:

1 <asp:ContentPlaceHolder id="ContentPlaceHolder1" runat="Server"></asp:ContentPlaceHolder>
2 <asp:ContentPlaceHolder id="ContentPlaceHolder2" runat="Server"></asp:ContentPlaceHolder>

Content Page:

1 <asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="Server"></asp:Content>
2 <asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder2" Runat="Server"></asp:Content>

Sorting a Custom Collection with Nested Class Types

Kyle — Thu, 12 Jan 2006 22:09:00 GMT

I have the need to sort a custom collection that contains sub classes. For example,

I've structured my classes like this:

Public Class Machine

  Private _Model as Model
  Public Property vModel as Model
    Get
      Return _Model
    End Get
    Set (ByVal Value as Model)
      _Model = Value
    End Set
  End Property

  Public Sub New()
    _Model = new Model
  End Sub

End Class

Public Class Model

  Private _ModelName as String
  Public Property ModelName as String
    Get
      Return _ModelName
    End Get
    Set (ByVal Value as String)
      _ModelName = Value
    End Set
  End Property

  Public Sub New()
    _ModelName = ""
  End Sub

End Class

I then made a collection of Machine objects like this:

Public Class MachineList

    Inherits CollectionBase

    Default Public Property Item(ByVal Index As Integer) As Machine
        Get
            Return CType(List.Item(Index), Machine)
        End Get
        Set(ByVal Value As Machine)
            List.Item(Index) = Value
        End Set
    End Property

    Public Function Add(ByVal Item As Machine) As Integer
        Return List.Add(Item)
    End Function

    Public Sub Remove(ByVal Item As Machine)
        List.Remove(Item)
    End Sub

End Class

Pretty straight-forward, right?

Well, there was no easy way to sort this. It's one of the Unsortable classes. As I was searching through the net, I found this article by Jan Tielens, which claims to be able to sort the unsortable collection. In normal circumstances, it does. However, I have nested custom classes. His solution only works on the first level.

So, I set to work trying to figure out a way, using Reflection, to pass in the Property name that I wanted to compare. (ie: "Model.ModelName"). Well, I parsed the Property Name at the Period, and used reflection to get the values in string form. Then, determined if they were numeric or not, and I compared them, and returned 0, -1, or 1, depending on the values. I then took my routine, and stuck it into Jan's Compare Routine. Voila, a custom nested class sorter. It'll go as deep as you want it to go.

At this point, it's dirty. I'll be working on a way to clean it up a bit, but it does what I want it to.

Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer _
      Implements System.Collections.IComparer.Compare
        Dim i() As Object
        Dim c As Integer = 0

        Dim tempSP() As String = PropertyToSort.Split(".")

        Dim v(tempSP.GetUpperBound(0)) As Object
        Dim b(tempSP.GetUpperBound(0)) As Object

        Dim temp As String

        Dim m As Machine = CType(x, Machine)
        Dim n As Machine = CType(y, Machine)

        For Each temp In tempSP

            v(c) = New Object()
            b(c) = New Object()

            Select Case temp

                Case "Model"
                    v(c) = m.GetType.GetProperty(temp).GetValue(m, i)
                    b(c) = n.GetType.GetProperty(temp).GetValue(n, i)
                Case Else
                    If IsNothing(v) Then
                        v(c) = m.GetType.GetProperty(temp).GetValue(m, i)
                        b(c) = n.GetType.GetProperty(temp).GetValue(n, i)
                    Else
                        If c > 0 Then

                            v(c) = CStr(v(c - 1).GetType.GetProperty(temp).GetValue(v(c - 1), i))
                            b(c) = CStr(b(c - 1).GetType.GetProperty(temp).GetValue(b(c - 1), i))
                        Else
                            v(c) = CStr(m.GetType.GetProperty(temp).GetValue(m, i))
                            b(c) = CStr(n.GetType.GetProperty(temp).GetValue(n, i))
                        End If

                    End If
            End Select

            c = c + 1

        Next

        c = c - 1

        If IsNumeric(b(c)) And IsNumeric(v(c)) Then

            If SortOrder = Windows.Forms.SortOrder.Ascending Or SortOrder = Windows.Forms.SortOrder.None Then
                If CLng(v(c)) > CLng(b(c)) Then
                    Return 1
                End If
                If CLng(v(c)) = CLng(b(c)) Then
                    Return 0
                End If
                If CLng(v(c)) < CLng(b(c)) Then
                    Return -1
                End If
            Else
                If CLng(v(c)) < CLng(b(c)) Then
                    Return 1
                End If
                If CLng(v(c)) = CLng(b(c)) Then
                    Return 0
                End If
                If CLng(v(c)) > CLng(b(c)) Then
                    Return -1
                End If
            End If

        Else

            If SortOrder = Windows.Forms.SortOrder.Ascending Or SortOrder = Windows.Forms.SortOrder.None Then

                Return String.Compare(CStr(v(c)), CStr(b(c)))

            Else

                Return String.Compare(CStr(b(c)), CStr(v(c)))

            End If

        End If

    End Function

I like the new MultiView Control

Kyle — Tue, 10 Jan 2006 17:51:00 GMT

So, I'm just getting into .NET 2.0. So far, I see what I like. Especially the MultiView control.

Simply place a MultiView Control on your page, add a couple of Views, and in the script, do a MultiView1.SetCurrentView(view1). Pretty straight forward.

At some point, I'll be trying to figure out how to utilize the Multi View control with Ajax.

Is there a type converter for the FontInfo Class?

Kyle — Tue, 27 Dec 2005 19:55:00 GMT

I'm working on developing a few server controls, and need to have a few "Font" properties in the control. Is there a type converter for the FontInfo class?

Anyone know?

Detecting Design Time in ASP.NET

Kyle — Mon, 26 Dec 2005 16:21:00 GMT

Here's a good little post about detecting design time in ASP.net.

I've been developing a suite of in-house tools lately in the form of custom controls, and outputting html to the designer has been critical. Good Stuff