Dynamic load whereparameters for linqDatasource

When using an Linq Datasource (linq to sql) for a datagrid (Gridview, ListView, etc) you don't always want all rows from a table. To exclute data you can use the WhereParameters to add an where statement to your DataSource.

You can do limited where statements with the Visual Studio Wizards. When you need more than a limited statement you can dynamicly create an Parameter to add to your Linq DataSource.

The following examples shows how to filter the Linq Datasource that recovers all rows from the Post table and filters them on the BlogId. The BlogManager.CurrentBlogId gets the blog GUID from the Session.


   Parameter whereparam = new Parameter();
   whereparam.Name = "BlogId";
   whereparam.DefaultValue = BlogManager.CurrentBlogId.ToString();
   whereparam.Type = TypeCode.Object;
   linqDataSource.Where = "BlogId == Guid(@BlogId)";


You cast the @BlogId (string) to a Guid In the linqDataSource.Where property otherwise you get the following error:

Operator '==' incompatible with operand types 'Guid' and 'String'

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.Query.Dynamic.ParseException: Operator '==' incompatible with operand types 'Guid' and 'String'

101 Linq samples

When learning and working with Linq. I had the need of reference samples. When searching for een example of the select syntax I stumbled on the follow site from Microsoft:

101 Linq Samples

It's a good reference guide for al your basic Linq query's.

Portofolio: MCPD certification course

To get more developers certified I started a MCTS learning course for the developers. Once in the two weeks all we had half a day to review two chapters, every chapter was reviewed by a developer.

Ten developers started the course and at this moment (20 April) six people are MCTS (Web) certified and one MCPD (and two employees left).

How to create a iGoogle Widget!

Because every eveloper needs to have a New Guid generator and .Net info search iGoogle widget ;-). It was time for me to create one!

I had no idea where to start, try searching Google no good results. But after clicking along on iGoogle I found the Google Gadgets developer site. After reading some documents and playing with some examples I found out that it is to easy to create a iGoogle widget. Here is a … step guide to create a iGoogle widget.

In this guide where going to load an external website (http://www.newguid.net/iGoogle_CreateGuid.aspx) in the widget (the most easy way to build a widget).

Step 1:
Go to the Google getting started document and scroll down to the Google Gadgets Editor. Here you can try out some examples or insert your own code.

Step 2:
Insert the following code to the Gadgets Editor 


<?xml version=”1.0″ encoding=”UTF-8″?>
  <ModulePrefs title=”[Widget Title]” height=”100″ author=”[Author Name]” author_email=”[Author Email]” description = “[Widget Description]” screenshot = “[Link to a Screenshot]” thumbnail = “[Link to a thumbnail]” author_link = “[Link to author website]”><Require feature=”dynamic-height”/>
  <Content type=”url” href=”http://www.newguid.net/iGoogle_CreateGuid.aspx”/>


Press the Preview tab. You will see that the New Guid widget is already working. The widget just loads the website within an Iframe. The best thing is that you only have to design an build your widget once on your own server. It is a normal page so there aren’t any design limits.

Step 3:
Save and Publish your widget. You have to change all properties (eg. title, author, author_email, etc.) in de code before you save and publish your widget. After you’ve changed the properties you can just save and then publish your widget. You can either publish your widget on your webpage (just by linking to it) or publish it into the Google Directory or both.

Publish your gadget in the editor by going to File > Publish. This button is only clickable if your syntax is correct.

Your gadget will be validated before the real publish. Fix all the issues that show in popup (see image below). And retry.



Like I told you to easy. Ofcourse you can do mutch more with it, but this will do for most of your widgets.


Using Google Custom Search Engine (CSE) with Asp .Net

I’ve been using Google Custom Search Engine (CSE) for one of my projects (searchTravelBlog). When I was trying to implement CSE in NewGuid.NET I found some problems doing this.The big issue is that CSE depends on the html FORM element with submit event for posting all the variables from the hiddenfields. 

The CSE code from Google looks like this:   

<form action="http://" id="searchbox_004900934070880588383:m5qbf6oxe6k">
      <input type="hidden" name="cx" value="004900934070880588383:m5qbf6oxe6k" />
      <input type="hidden" name="cof" value="FORID:11" />
      <input type="text" name="q" size="25" />
      <input type="submit" name="sa" value="Search" />


When you copy this code into a .Net page it will not work. This because of the default .Net server form tag.

If you want to use CSE within your .Net page don't use Google's code that generates the search form.  Create your own code, just add one Textbox and one Button control to your page.

<asp:TextBox ID="searchQuery" runat="server" size="30" />
<asp:Button runat="server" Text="Search .Net Info" ID="searchButton" OnClick="searchButton_Click" />


In the code behind you add the following searchButton_Click event:

protected void searchButton_Click(object sender, EventArgs e)
   StringBuilder redirectUrl = new StringBuilder();
   //The URL to your resultpage
   //Add your CSE unique identifier
   //Add your advertising location code
   //The search query
   redirectUrl.Append("&q=" + searchQuery.Text);
   //Redirect to the resultpage


You can find these values in the hidden values from the default code that Google creates for you.It is important that the values within the redirectUrl are html encoded.

Add the following code to your Page_PreRender so that the searchquery will appear in the textbox.

protected void Page_PreRender(object sender, EventArgs e)
   searchQuery.Text = Request.QueryString["q"];


Note: This example doesn't include the branding that Google requires. Please read the branding guidelines here!

obout Suite for .Net 2.0

When surfing around I found this great range ASP.Net controls.  Obout.com offers a great variety of ASP and ASP .Net controls. The controls are Cross-Browser (including Safari  and Opera).You can download the obout Suite for .Net 2.0. The suite contains the following controls:

  • TreeView  (recommended)
  • Grid
  • Editor
  • Spell checker
  • Calendar
  • Easy menu
  • Combobox
  • Slide menu
  • AJAXPage
  • Two colors menu
  • Splitter
  • Super button
  • Tree_DB
  • Autosuggest
  • Show
  • Flyout Window
  • FileUploadProgress
  • Slide Panel (with Slide menu)
  • TabStrip (with Easy Menu) 
  • Context menu (with EasyMenu)
  • Toolbar (with Supper button)
  • State Selector (with Combobox)

There are loads of examples on their website. So go check it out!