Author Archives: Yuriy

WARP, UltraWebGrid and ScriptManager glitch in IE6 and IE7

This is probably a very obscure situation, but it happened to me, it could happen to someone else. Scenario: an ASP.NET page with Infragistics UltraWebGrid inside of a WARP panel. A button outside the WARP serves as a trigger for partial postback. First click on the button causes expected partial postback, but on the second click page does full postback and is screwed after that. The issue happens only in IE6/7, page works correctly in IE8.

Another condition – page contains ASP.NET AJAX ScriptManager control with ServiceReference path pointing to an ASMX WebService.

Turned out the issue was caused by project being left in debug mode (in web.config debug=”true”). Which caused WebService page to be loaded with parameter “jsdebug” in query string. Which apparently IE6 and 7 didn’t like very much. Switching to debug=”false” in web.config solved the problem.

How to Disable hyperlink clicks

Hyperlinks are designed for clicking, to lead you somewhere else, but sometimes this  behavior is undesired. In my case a grid control displayed some HTML data in its cells (including hyperlinks) and clicking on those links caused some undesired effects. I still wanted to display HTML and allow clicking on other grid elements (e.g. checkboxes) just needed a way to prevent hyperlinks clicks.

Remember that events bubble? That gave me an idea to wrap the grid control in a DIV to catch click events. This way I can check event source and if it’s a hyperlink – cancel the event, otherwise allow it. Well that’s pretty much it. Here’s a stump for the DIV wrapper:

<div onclick="return checkClickSrc()">
    <!-- Controls to check go here-->
</div>

and here’s the JavaScript code that does the check:

function checkClickSrc() {
    return event.srcElement.tagName != 'A'
    //for firefox: return event.target.tagName != 'A'
}

Excellent Freeware RAR password recovery utility

If you ever need to recover lost password to your RAR file (or, let’s be honest, unrar a file you got from the Internet), look no further than cRARk – beautifully done RAR password recoverer. It’s the only utility capable of using NVIDIA CUDA, which utilizes GPU for password permutations, and even without that it’s extremally fast. And it’s free!

You can download it at http://www.crark.net

“Cannot find column” DataTable error while grouping or sorting Infragistics UltraWebGrid

If you’re binding an ADO.NET DataTable to Infragistics UltraWebGrid and then programmaticaly sort the grid (e.g. add a column to a band’s SortedColumns collection) you may get an error:

Cannot find column My Column Name.

with stack trace starting from grid databinding and finishing in datatable’s sorting:

at System.Data.DataTable.ParseSortString(String sortString)
at System.Data.DataView.CheckSort(String sort)
at System.Data.DataView.set_Sort(String value)
at Infragistics.WebUI.UltraWebGrid.DBBinding.ProcessDataViewForFillRows(DataView dataView, RowsCollection rows)
at Infragistics.WebUI.UltraWebGrid.DBBinding.FillRows(UltraWebGrid grid, RowsCollection rows, IEnumerable datasource)
at Infragistics.WebUI.UltraWebGrid.DBBinding.BindList(IEnumerable datasource)
at Infragistics.WebUI.UltraWebGrid.DBBinding.DataBind(Object dataSource, String dataMember)
at Infragistics.WebUI.UltraWebGrid.UltraWebGrid.DataBind()

If the grid binds OK without sorting and grouping, but fails with either – most likely the culprit is one of the columns in data table. Continue reading →

Displaying consistent number of links in Infragistics UltraWebGrid Pager

In the previous post I described how using QuickPages property and a bit of creative HTML enhanced pager for Infragistics UltraWebGrid could be created. The only problem with QuickPages – the pager in this mode displays inconsistent number of page links. For example if you set QuickPages property equal 5, the pager will display from 5 page links (when you’re at the beginning or at the end of the grid) to 11 (when you’re in the middle). If you want that number to be consistent, you have to draw the page links yourself. Which turned out is surprisingly easy. Continue reading →

ASP.NET Chart Control is not rendering image

If you’re using MS Chart Control for .NET Framework 3.5 SP1 (in .NET Framework 4.0 it comes as a part of a framework), you may experience a strange behavior when chart images aren’t rendered on the page:

Chart image isn't rendering

If you’re using HTTP Handler to serve chart images (image URL looks something like “…/ChartImg.axd?i=chart_24dae5cb1f024c4a89f4fe492f05cc59_0.png“) missing mapping in IIS configuration could be to blame Continue reading →

Selectively change cell type in Infragistics UltraWebGrid

When you design columns for UltraWebGrid, one of the settings available to you is Column Type. For example you can set it to Button, and all cells within the column will render and behave as HTML buttons. Other options available such as Check Box or Hyperlink.

But what if you want some of the column cells to be of a different type? For example some of cells aren’t supposed to be links, but plain text instead? The solution is to set Column Type of those cell thru code. Consider following example:

Protected Sub xmyGrid_InitializeRow(ByVal sender As Object, ByVal e As RowEventArgs) Handles xmyGrid.InitializeRow
    If e.Row.Index > 0 Then
        e.Row.Cells.FromKey("LINK_CELL).TargetURL = "http://mysite.com?ID=" & e.Row.Cells.FromKey("LINK_ID)
    Else
        e.Row.Cells.FromKey("OBJ_NAME").Column.Type = ColumnType.NotSet
    End If
end sub

Above is a handler for UltraWebGrid’s InitializeRow event. It checks if a row is a first row in the grid and if so – sets its column type to “NotSet” effectively removing “Hyperlink” type set at design time. And even though it references type of entire column – the change applies only to the current cell.

IE8 Idiotic Session handling

As you may be aware Internet Explorer 8 will share session among its different instances (even if you start new instance by clicking IE Desktop icon). Why on Earth this was done is described in this article. The only way to start a new session is to use obscure File -> New Session option in menu, interesting choice, considering that in IE8 menu is hidden by default.

But this is not the end. Quoting the article:

Relying on closing the window to clear the session is not a recommended way to implement proper logoff for an application. Because this clearly will not work if there is another window that is sharing the session.

True, buy why, pray say, session isn’t cleared for one application if its window closed, but another window remains open, pointing to a completely different application, on different server in different DOMAIN?!

Do try this:

  1. Login to any app that that requires user login.
  2. Open a new browser, and point it anywhere to a completely unrelated link.
  3. Close original app window from Step 1.
  4. Open new browser window and go URL of app from Step 1.
  5. Surprise, surprise, you’re still logged on.

Also, aren’t  they aware that 99.9% of all users will simple close browser window instad of going thru logout process even if it takes only one click? And in many scenarious, including one above user will stay logged in.