Tag Archives: solution

@@ROWCOUNT is affected by IF statement

Let’s say you’re writing T-SQL code and need to make sure that your query returns one and only row. If no records returned – an error message needs to be shown. If more than one record is returned – another error message needs to be show. The code goes something like this:

-- ... query runs here and returns row

IF @@ROWCOUNT = 0 RAISERROR('No records found', 18, 1)
ELSE IF @@ROWCOUNT > 0 RAISERROR('More than one record found', 18, 1)

-- ... continue when exactly one row is returned

Now if your query returns 3 records you’d expect it to trip the second IF statement and raise error with correct message. Unfortunately this doesn’t happen. The reason being – the first IF statement resets @@ROWCOUNT to 0. So, to avoid this we need to preserve the @@ROWCOUNT value in a local variable:

DECLARE @iRowCount int

-- ... query runs here and returns row

SET @iRowCount = @@ROWCOUNT

IF @iRowCount = 0 RAISERROR('No records found', 18, 1)
ELSE IF @iRowCount > 0 RAISERROR('More than one record found', 18, 1)

-- ... continue when exactly one row is returned

This way count of rows returned by the query is saved and is not affected by any following statements.

UltraWebGrid TopItemSpacing=”Auto”: Solution for FireFox

If you’re still using classic Infragistics Controls and want to make them work in modern browsers, sometimes a little additional work is required. Hopefully this little trick will save you some time.

UltraWebGrid has a neat property TopItemSpacing, when set to Auto it automatically spreads top level menu items across the menu control, giving them nice spacing in between. Unfortunately this property seems to work in Internet Explorer only, in Firefox (and Chrome and etc.) it is ignored, rendering menu in Compact mode giving top level items crowded “too-close-for-comfort” look.

The solution is to take spacing in our own hands. Set TopItemSpacing to Compact and instead add right padding to TopLevelParentItemStyle and TopLevelLeafItemStyle elements of the menu. For example (from the markup point of view):

<TopLevelLeafItemStyle Cursor="Hand" Height="18px" BorderWidth="1px" Font-Size="8pt">
   <Padding Right="6px" />
</TopLevelLeafItemStyle>

Actual pixel value of the padding is up to your particular scenario, but the final result is top level menu items will be nicely spaced both in IE and in Firefox.

WebDataGrid: Prevent scrolling on row selection

If you working with Infragistics Aikido controls and your WebDataGrid or WHDG is too long – a common approach to make content scrollable is to place grid control inside of a DIV with fixed dimensions and overflow set to auto:

WHDG scrollable inside of parent DIV

It works fine, but there’s one drawback: if you scroll your grid horizontally and then select a row – grid’s scroll position snaps back to the leftmost position. Infragistics says that it’s a browser bug and we need to talk to browser vendor about it. Wanting to solve the problem in this century I looked for alternatives and this is what I found. Continue reading →

UltraWebMenu: When background doesn’t change on hover in IE9

If you tried to use Infragistics classic UltraWebMenu control in IE9 you may experience issue (even in the latest version, 11.2 at the time of this post) whereby menu items don’t change background on mouse hover even though background is specified in menu’s HoverItemStyle property.

The solution is specify BorderStyle in HoverItemStyle. It can be any value besides NotSet, but the actual attribute has to be there. So for example if you want your hover style to have no borders and your original style looks like:

<HoverItemStyle
   ForeColor="White" 
   BackColor="#81C0E9"
   Height="18px"
   BorderWidth="0px"> 
</HoverItemStyle>

change it to

<HoverItemStyle
   ForeColor="White"
   BackColor="#81C0E9"
   Height="18px"
   BorderWidth="0px" 
   BorderStyle="None">
</HoverItemStyle>

I don’t know why border style affects showing of the background, but there you have it. Adding BorderStyle to HoverItemStyle will enable displaying of background color on hover.

ClientScript.RegisterStartupScript: script injected, but not executed

This was one weird mystery. I have used ASP.NET’s method ClientScript.RegisterStartupScript countless times to inject client-side JavaScript into page’s markup from the server-side code and it always worked perfectly. This time I created a very basic page from scratch:

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>My Page</title>
    <script type="text/javascript" src="script1.js" />
    <script type="text/javascript" src="script2.js" />
    <script type="text/javascript" src="script3.js" />
</head>
<body>
    <form id="xfrmMain" runat="server">
    </form>
</body>
</html>

And then injected client-side script into it:

ClientScript.RegisterStartupScript(Me.GetType, "JSCode", "ProcessData();", True)

where ProcessData() is function from one of the scripts, loaded in the HEAD tag. The script injected just fine, I got a beautiful insert at the bottom of the rendered page:

<script type="text/javascript">
//<![CDATA[
ProcessData();//]]>
</script>

The problem was – it didn’d do squat – the script did not execute. Why? Continue reading →

How to load IFRAMEs in order according to priority

Let’s say you have a Web page that displays “widgets” a small islands of information. And internally those widgets are IFRAME elements, whose source is loaded dynamically from the same server at runtime in client side JavaScript. So, you have a code similar to this:

var aIframes = document.getElementsByTagName('IFRAME');
for (var I = 0; I < aIframes.length; I++) {
    aIframes[I].src = aIframes[I].getAttribute('originalURL')
}

This (oversimplified) code assumes that URL for IFRAME source already stored as a custom attribute ‘originalURL’ of IFRAME element (for example placed there by server-side code), but it can equally come from other sources. This approach is usually taken so IFRAMES can initially display a static page with “Please wait. Loading…” animation meanwhile dynamically loading real data – creates a better user experience.

The code loops thru all IFRAMEs setting their SRC attribute, displaying content, so you would see something like

IFRAME widgets

It’s all well and good, but there’s a small problem. SRC of IFRAMEs is assigned in order of their appearance on the page and if URLs are pointing to the same server and one of the earlier IFRAMEs takes a long time to load – it will block the rest of the IFRAMEs from loading. Continue reading →

WHDG: RowIslandsPopulating event fires multiple times

I’ve been successfully using manual load on demand in WebHierarchicalDataGrid for a while now, but recently noticed strange thing. The deeper in grid’s hierarchy I expanded the children – the slower it went.

In my case every time user clicks [+] to expand a row, VB.NET code calls an SQL Server Stored procedure to bring in child rows. I grew suspicious and fired up SQL Profiler. What I saw surprised me. Number of calls to the stored procedure increased the deeper in grid’s hierarchy I expanded the children. When I clicked [+] on the root level it resulted in 1 SP call. Clicking [+] on the child to expand grandchild – 2 calls. Expanding grandchild to see grand-grandchild rows – 3 calls, etc. Continue reading →

onbeforeunload event is fired on click

onbeforeunload browser’s event fires when the window is about to navigate to another page or about to be closed. So why why would it fire when you click to call a JavaScript function that does neither of the two?

If your have your click setup similar to something like this:

<a href='javascript:doStuff()'>Click to do something</a>

or, if you’re using ASP.NET’s HyperLink control:

<asp:HyperLink ID="xhypMuLink" runat="server" NavigateURL="javascript:doStuff()">
   Click to do something
</asp:HyperLink>

And your “doStuff()” function doesn’t redirect or closes the window – you’d expect it just do its stuff and that’s it. But in addition to it, or rather before it onbeforeunload event fires, so if you have some code in the event handler – it will be executed, which in this case is undesirable.

Why does it happen? Continue reading →