Infragistics WebHierarchicalDataGrid offers a nice ability to custom load-on-demand data via its ContainerGridDataBinding event. It is very useful during paging or displaying grid children – you can make a DB call and provide data a just needed for current page or child.
But it has a drawback – if you need to programmaticaly sort the grid by manipulating SortedColumns collection – grid thinks it needs to rebind the data and is calling ContainerGridDataBinding event handler again thus making it execute DB call again – which is redundant and may hinder performance. In a typical scenario you have your binding code:
Protected Sub xmyGrid_ContainerGridDataBinding(sender As Object, e As GridControls.DataBindingEventArgs) Handles xmyGrid.ContainerGridDataBinding
e.Cancel = True
e.DataSource = MakeDbCallToGetCurrentData()
e.SelectArguments.TotalRowCount = iTotalNumberOfRecords
End Sub
and somewhere else add sorting
Protected Sub xmyGrid_PreRender(sender As Object, e As EventArgs) Handles xmyGrid.PreRender
xmyGrid.Behaviors.Sorting.SortedColumns.Add(sCol1Key, SortDirection.Ascending)
xmyGrid.Behaviors.Sorting.SortedColumns.Add(sCol2Key, SortDirection.Descending)
End Sub
Sorting code in the second event handler is causing grid to perform second call to ContainerGridDataBinding. The solution is to move sorting code inside of ContainerGridDataBinding handler:
Protected Sub xmyGrid_ContainerGridDataBinding(sender As Object, e As GridControls.DataBindingEventArgs) Handles xmyGrid.ContainerGridDataBinding
e.Cancel = True
e.DataSource = MakeDbCallToGetCurrentData()
e.SelectArguments.TotalRowCount = iTotalNumberOfRecords
xmyGrid.Behaviors.Sorting.SortedColumns.Add(sCol1Key, SortDirection.Ascending)
xmyGrid.Behaviors.Sorting.SortedColumns.Add(sCol2Key, SortDirection.Descending)
End Sub
Since at this point grid already bound to data – columns are already available. And since we’re inside of ContainerGridDataBinding – the call to it is not repeated.
Infragistics WebHierarchicalDataGrid has a neat client-side built-in function get_scrollTop() – it is used if at any point you need to retrieve current vertical scroll position of the grid (e.g. to use it in your own calculations to display something at a specific position on the grid – tooltip, help, additional info etc.)
Unfortunately the function has a bug: its value only set if user actually manually scrolls the grid: using mouse and scrollbar on the right, keyboard etc. If no scrolling user-interaction is involved and scroll position changes due to other means (e.g. displayed data size changes) – the function retains original value, throwing all your calculation out of whack. Continue reading 'WebHierarchicalDataGrid: get_scrollTop() returns incorrect value'»
This is a solution for specific (and maybe somewhat obscure, but it helped me, so perhaps it will be helpful to someone else) scenario for Infragistics’ WebHierarchicalDataGrid error “Async request failed“.
It could be accompanied by inner errors
Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request
If you’re using Infragistics WebHierarchicalDataGrid and getting “DataKeyField is invalid” error after assigning DataKeyFields property for the root level:
xMyGrid.DataKeyFields = "[Key 1],[Key 2],[Key 3]"
and trying some data manipulation (like deleting rows, binding data etc.), try using GridView property of the grid instead:
most likely it’s because grid’s ItemCssClass property is used. In theory (at least according to ever so verbose documentation) it should define what grid’s cells look like. In practice it have no effect whatsoever. Or rather had no effect until upgrade (verified in version 2011.1, perhaps even earlier). Now if your CSS class used in this property contains HEIGHT attribute – a blank row of that height will be inserted on top of the grid.
Upgrading 3rd party library to a new version is bound to have problems and Infragistics is no exception. In my case I was upgrading NetAdvantage for ASP.NET from version 2009.2 to to 20011.1 and right away WebHierarchicalDataGrid started to crash client-side. If ScriptManager was in debug mode I’d get error:
Microsoft JScript runtime error: Sys.ArgumentUndefinedException: Value cannot be undefined.Parameter name: type
With ScriptManager in Release mode it’d be:
Microsoft JScript runtime error: Object expected
But always in Sys.Component.Create – it looked like grid’s client-side scripts weren’t loading at all. After A LOT of digging I found out that the culprit was grid’s server-side Bands.Clear() method. When called, it caused client-side WHDG JavaScript not to load. When that method was commented – JavaScript errors disappeared. So until Infragistics comes out with a bug fix – if you experience similar problem, try to avoid Bands.Clear() method.
The WHDG has correctly displayed HTML fields before, but this time a column with HTML data (an HREF link to be precise) is needed as one of the grid’s DataKeyFields to provide uniqueness of the row:
If you need to get/set value of a specific cell in WHDG Row (which is of GridRecord or ContainerGridRecord type) the only way to do it is by Cell index e.g.
Protected Sub xMyGrid_InitializeRow(ByVal sender As Object, ByVal e As GridControls.RowEventArgs) Handles xMyGrid.InitializeRow
e.Row.Items(15).Value = 42
End Sub
But what if you don’t know cell/column index and only column name is known? Then the trick is to find the index first. Consider following code:
Protected Sub xMyGrid_InitializeRow(ByVal sender As Object, ByVal e As GridControls.RowEventArgs) Handles xMyGrid.InitializeRow
Dim oParent as GridControls.ContainerGrid = e.Row.Items.Grid
Dim iColIndex as Integer
if oParent.Columns("MY_COLUMN_NAME") IsNot Nothing
iColIndex = oParent.Columns("MY_COLUMN_NAME").Index
e.Row.Items(iColIndex).Value = 42
End If
End Sub
It’s pretty straightforward, first you locate grid to which the row belongs, then locate column in that grid by name and get index of that column and finally locate cell in the row by that index. This method will work at any depth in the WHDG hierarchy.
Working with row selection in Infragistics WebHierarchicalDataGrid can be complicated since it maintains independent row selection collection for each row island and basic operations (select/unselect) aren’t that obvious. I put together a few functions to make it a little bit easier.
This first function is very basic, it returns total count of selected rows across all expanded row islands, no matter what depth. The key here is get_selectedRowsResolved() method of Selection behavior which returns an array of all selected rows:
// Returns number of selected rows from all rowislands in WebHiearchicalDataGrid
// i_oGrid: Infragistics WebHiearchicalDataGrid object
function selRowsCount(i_oGrid) {
return i_oGrid.get_gridView().get_behaviors().get_selection().get_selectedRowsResolved().length
}
The following function loops thru all selected rows, collecting values from specific column (useful for example for collecting IDs of selected rows). It accepts 3 parameters – WebHiearchicalDataGrid object, column key and separator character and returns a string in which selected values are separated by that character (if nothing is passed – default separator is comma). Continue reading 'WebHierarchicalDataGrid: Helpful client functions for row selection'»
In the previous post I described a method to automatically resize columns for Infragistics grid control. It works (most of the times) for flat WebDataGrid, but if you try same approach with WebHierarchicalDataGrid – it will fail for child bands.
Lets review what we’re trying to accomplish. A grid column should automatically resize to whichever is wider: either size of widest data in a column cell, or size of column header’s caption.
First is accomplished by not setting column width explicitly and by setting white-space attribute of cell’s style to nowrap. It can be done by either opening grid CSS class file located at~/ig_res/[Your Style Name]/ig_dataGrid.css, locate tbody.igg_[Your Style Name]Item>tr>td class and add one more line at the end: white-space:nowrap. Here is an example with Office 2007 Style:
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