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New Post 5/25/2011 7:42 AM
  Ewans
777 posts
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Virtual DataGridView 
Modified By Ewans  on 5/11/2012 9:00:18 AM)

Hi

How efficient are the just in time methods used to pouplate the datagrid view?

Would it be wise to use this new control using a bound SQL datasource, assuming there is a bulit in mechanism to manage grabbing the data just in time?

Can you use the standard DGV events wiith this control for updateing and validting data or should the events normally associated with a virtual DGV be used instead? Does this depend on whether you have VirtualMode set or not?

Thanks for your help

Ewan

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New Post 5/25/2011 2:31 PM
  palli
16672 posts
1st Level Poster




Re: Virtual DataGridView 

Hi Ewan,

As far as my tests have shown so far, the VirtualDataGridView is very efficient. Take a look at the code in this thread here for instance, where I was experimenting with 100 thousand rows in a VirtualDataGridView.

The VirtualMode, as implemented by Windows Forms DataGridView, is not implemented yet though, as the required events for that implementation do not fire in Visual WebGui (CellValueNeeded, CellValuePushed, NewRowNeeded....). In that sense the VirtualDataGridView is not virtual in terms of on demand data retrieval from the underlying datasource.

For the virtuality in the VirtualDataGridView, you would set UseInternalPaging = false, and then with a huge datasource, you would get a "single page" scrollable DataGridView for all of your data.

The API for the DataGridView and VirtualDataGridView is identical, so yes, you would use the same event code. In fact, you should be able to change your existing DataGridView controls to VirtualDataGridView controls with just minimal efforts, more or less just replacing the type signature in your designer generated source files (or the equivialent ones, if dynamically created). Same column types are used, so DataGridViewTextBoxColumn is used for both controls.

Hope this helps,

Palli

 

 


Páll Björnsson - Visual WebGui support team - Email: support@visualwebgui.com

Please include VWG version information with your questions (best: Full name of VWG installation .MSI file)
To send sample code or other files to support, first zip the relevant project or files,
then rename .ZIP file to different extension like .XIP and finally email as attachment to email address above.
Remember to include full Http Url to the forum thread in the message.
 
New Post 5/26/2011 3:25 AM
  Ewans
777 posts
1st Level Poster




Re: Virtual DataGridView 

Hi Palli

Thanks - my tests using your code showed that setting UseInternalPaging makes no difference, you still will only get a single scrollable page.

So the virtual bit is between the datatable in memory on the server and the client?

Is it possible to page the data so it loads a page at a time, instead of whenever you scroll?

Thanks for your help

Ewan

 
New Post 5/26/2011 11:09 AM
  palli
16672 posts
1st Level Poster




Re: Virtual DataGridView 

Hi Ewan,

You are correct that the virtualization of the VirtualDataGridView is between the in-memory datasource on the server and the client.

The VirtualDataGridView is already paged, and you can set the blocksize via VirtualDataGridView.VirtualBlockSize property.

In addition and for the record, I just added a new enhancement request for consider implementing VirtualMode (or similar behaviour) that would allow you to load data from the datasource into server's memory on demand. Please view it here and follow up on our progress.

Palli

 


Páll Björnsson - Visual WebGui support team - Email: support@visualwebgui.com

Please include VWG version information with your questions (best: Full name of VWG installation .MSI file)
To send sample code or other files to support, first zip the relevant project or files,
then rename .ZIP file to different extension like .XIP and finally email as attachment to email address above.
Remember to include full Http Url to the forum thread in the message.
 
New Post 5/27/2011 5:06 AM
  Ewans
777 posts
1st Level Poster




Re: Virtual DataGridView 
Modified By Ewans  on 5/27/2011 8:06:38 AM)

Hi Palli

Thanks for clarifying.

My tests show that changing the following settings seems to have no effect

UseInternalPaging

Total Pages

Ewan

 

 
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