Sep 23, 2010

DataGridView Reentrant Error

The events on a datagridview seems to be unstable when there is a need to repopulate a datagridview within its events. It does makes sense as if you have a trigger on any change and to populate the grid, it can lead to an infinite loop. One of the errors I encountered was

System.InvalidOperationException was unhandled
Message="Operation is not valid because it results in a reentrant call to the SetCurrentCellAddressCore function."

In fact I had to repopulate the datagridview on CellEndEdit. I Googled a lot about it and found some solutions. I came up to something, which I am not sure is the most efficient one, but it works.

public delegate void InvokeDelegate();

private void datagrid_changed(object sender, EventArgs e)
    this.dataGridView.BeginInvoke(new InvokeDelegate(ModifyGrid));

private void ModifyGrid()
    // Method implemented to change datasource

Instead of modifying the datasource directly, I had to pass though a delegated called by BeginInvoke. It should work fine.

In WPF DataGrid it is as follows:

private void dataGridLines_RowEditEnding(object sender, EventArgs e)
    Dispatcher.BeginInvoke(new InvokeDelegate(InsertRow), null);

Sep 20, 2010

Dynamic Inline Styling

Microsoft Outlook 2007 and also the version 2010 are very bad at rendering HTML. They use Word to render HTML! There has been holly war on this issue but we have to deal with it for years to come.

Let me explain the problem briefly, emails in general requires inline styling as webmails like Gmail and Hotmail strips all stylesheet files. Outlook is the worst and needs table, so generally speaking if you want the email to appear correctly, the email must be done in tables with inline styling. When many websites are running on the same code, it is difficult to use the same email template for all sites. The quick solution would be to create a template for each one. But let me suggest another idea.

What I did was that the email template was made the same with classes, just as you would do for a site:
<table border="0" cellspacing="0" class="tableContent">{some content}</table>

Afterwards, the css file is not actually a css file, but a php file that contains an array, it will all make sense afterwards:
$style_email['class="tableContent"'] = 'style="font-family:tahoma, arial; font-size:11px; color:#222222;"';

All the styles are defined like that, then just do a str_replace, the $email_order contains the email template:
global $style_email;

//include default css
include (DEFAULT_CSS);

//overwrite some css if needed
if (file_exists (SITE_CSS)) {
    include (SITE_CSS);

foreach($style_email as $key=>$value) {
    $inline_email_template = str_replace($key, $value, $email_template);

It is pretty neat and works really well, you can continue further more, by including the default css first and then including the particular css and strip div and span tags. There you are, the email can be coded with class and it will be shown on all browsers.

Hello there!

Hello there! This is Kervin Ramen. I am tying out blogging experience with Blogger.