ClientScript.RegisterStartupScript(Me.GetType, "JSCode", _
                  "function MyAlert() {alert('This is the FIRST call')}", True)

Function is generated, and in due time, when needed is called by the client and the message “This is the FIRST call” is displayed. All is well.

Now, your page also has an UpdatePanel, and during a partial postback you need to modify that client-side function:

ScriptManager.RegisterStartupScript(Me, Me.GetType, "JSCode", _
                  "function MyAlert() {alert('This is the SECOND call')}", True)

In due time, when again needed by client code, function MyAlert is called and the message (wait for it, you’re in for a surprise) “This is the FIRST call” is displayed again. Originally generated function is called and second generation is ignored.

To rectify the situation you need to declare function as a variable (empty initially) in your client code:

var MyAlert;

And then modify server-side generation code to use assignment notation (instead of function MyAlert use MyAlert = function):

Initial load:

ClientScript.RegisterStartupScript(Me.GetType, "JSCode", _
                  "MyAlert = function() {alert('This is the FIRST call')}", True)

and partial postback

ScriptManager.RegisterStartupScript(Me, Me.GetType, "JSCode", _
                  "MyAlert = function() {alert('This is the SECOND call')}", True)

after these changes client-side code behaves as expected and freshly generated function is called every time.

Let’s get back to basics, namely Northwind database. If I ran a query like this:

SELECT * FROM Customers

I will get a result, similar to this:

Now to the weird part. Let’s say I need to sort this query by by Contact’s title and Contact’s last name. I don’t know what the column name for the Contact’s title will be, but I know if will always be a static 4th column. I don’t know where in the resultset Contact’s full name be located (it could be 3rd, or 8th or whatever column) but I do know it will always be called ContactName.

There query for this scenario would be:

SELECT * FROM Customers
ORDER BY 4, RIGHT(ContactName, LEN(ContactName) - CHARINDEX(' ', ContactName))

Here we first sort by the 4th column (ordinal position for column with Contact’s title and unknown name) and then by a string expression that extracts last name from ContactName column. The result:

'
' define Exporter "xMyExporter"
' define UltraWebGrid "xMyGrid" and load grid with data, then:
'
xMyExporter.ExportMode = UltraWebGrid.ExcelExport.ExportMode.Download
xMyExporter.Export(xMyGrid)

That’s it. But, if your data exceed 65536 rows you will get an error:

System.InvalidOperationException: The maximum number of rows in an excel worksheet with the current format is: 65536

This is not Excel Exporter limitation. In fact this is a limitation of Excel 2003 XLS format, which is a default output format of the Excel Exporter. The good news – this can be easily changed. Consider the following code:

'
' define Exporter "xMyExporter"
' define UltraWebGrid "xMyGrid" and load grid with data, then:
'
Dim oBook As New Excel.Workbook(Excel.WorkbookFormat.Excel2007)

xMyExporter.ExportMode = UltraWebGrid.ExcelExport.ExportMode.Download
xMyExporter.Export(xMyGrid, oBook)

In this version we first defined an Excel Workbook (Line 5) and gave it Excel 2007 format. And then used that workbook in actual export (Line 8). Which produces an Excel 2007 XLSX format capable of storing over 1 million rows.

[ArgumentException]: The image is not found. at
System.Web.UI.DataVisualization.Charting.ChartHttpHandler.ProcessSavedChartImage(HttpContext context) at
System.Web.UI.DataVisualization.Charting.ChartHttpHandler.System.Web.IHttpHandler.ProcessRequest(HttpContext context) at
System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I could be intermittent, sometimes happen, sometimes not. In your web.config you already set your temp images to be stored as files and not deleted after serving:

<add key="ChartImageHandler" value="storage=file;timeout=20;url=~/temp/;deleteAfterServicing=false" />

as well as trying other remedies and nothing helps.

One possible solution is, while still using file temp storage, instead of indicating relative path via url property set it to absolute path via dir property:

<add key="ChartImageHandler" value="storage=file;timeout=20;dir=C:\TEMP;deleteAfterServicing=false" />

In the example above C:\TEMP is an absolute path to the temp folder on the Web Server. In your case it could be different; in multi-server (WebFarm) environment it should be a network share, accessible by all servers.

From oRow As DataRow In dtTable.Rows Select oRow Distinct

or

(From oRow As DataRow In dtTable.Rows Select oRow).Distinct()

You may find that rows that are being return are not unique. That’s because by default LINQ compares table rows by reference. If you need to compare by actual values – use DataRowComparer in Distinct method call:

(From oRow As DataRow In dtTable.Rows Select oRow).Distinct(DataRowComparer.Default)

Now this just bring a nostalgic tear to your eye. Cory Smith of AddressOf implemented Classic DOS GW BASIC entirely in Silverlight. It’s beautiful, give it a go!

‘this.Column.Band’ is null or not an object

The solution to this is to close filter dropdown ourselves. Put these lines into your client-side code whenever clicking outside the filter doesn’t close it:

var aGridCols = igtbl_getGridById('xMyGrid').Bands[0].Columns
   for (var I = 0; I < aGridCols.length; I++)
      aGridCols[I].showFilterDropDown(false);

Here we’re looping thru grids column collection (This example assumes grid is in Flat or OutlookGroupBy mode, if your grid is hierarchical, you will have to loop thru band collection as well). For every column we pass False to showFilterDropDown method which (probably showing Infragistics cute sense of humor) hides filter dropdown if it is open. If dropdown is hidden for the column already – nothing happens.

As a result opened filter dropdown is now always closed prior to previously offending action and the error doesn’t happen.

In my case it was most felt when grid (which had ViewType="OutlookGroupBy") was initially grouped with a lot of data in each group and then ungrouped back into flat view when user dragged last group column out. Using IE9 built-in developer tools I ran JavaScript profiler I found that culprit was Infragistics JS function “disposeNode” which was called numerous times and had worst both inclusive and exclusive execution time.

Apparently what was happening – before bringing in fresh data grid was destroying all XML nodes of existing data, which – when grid is grouped with a lot of data in each group – is a lot of nodes. I decided to test what would happen if I destroy all top-level nodes in advance, so grid’s code won’t have to recursively loop through each one of them. I did this with just these 2 lines of JavaScript code:

var oGrid = igtbl_getGridById('xMyGrid');
if (oGrid) oGrid.Rows.SelectedNodes.removeAll();

Basically here we get a reference to grid’s client-side object and clear all nodes associated with grid’s rows. My grid didn’t use it’s own AJAX “LoadOnDemand” features and was located inside of Infragistics WARP panel, so I put that code inside of WARP panel’s RefreshRequest event handler which is called before grid’s server-side rebind. Your setup may be different, but you just have to run these lines before grid gets new data.

Result: Rendering in the client almost 90% faster.

CREATE TABLE #Employees (Country varchar(50), FirstNames varchar(50))

INSERT INTO #Employees(Country,FirstNames)
	 VALUES ('UK','Anne,Michael,Robert,Steven')
INSERT INTO #Employees(Country,FirstNames)
     VALUES ('USA','Andrew,Janet,Laura,Margaret,Nancy')

SELECT Country, FirstNames FROM #Employees

That looks like this

Country  FirstNames
UK       Anne,Michael,Robert,Steven
USA      Andrew,Janet,Laura,Margaret,Nancy

and now you need to split FirstNames so that every FirstName is displayed on separate row.
First we need a function to split strings. There’re plenty solutions, for example you can use one found by Cade Roux @ StackOverflow:

CREATE FUNCTION dbo.Split (@sep char(1), @s varchar(512))
RETURNS table
AS
RETURN (
    WITH Pieces(pn, start, stop) AS (
      SELECT 1, 1, CHARINDEX(@sep, @s)
      UNION ALL
      SELECT pn + 1, stop + 1, CHARINDEX(@sep, @s, stop + 1)
      FROM Pieces
      WHERE stop > 0
    )
    SELECT pn,
      SUBSTRING(@s, start, CASE WHEN stop > 0 THEN stop-start ELSE 512 END) AS s
    FROM Pieces
  )

Once we have it, it’s only a matter of joining function results with remaining fields from the original table (Note CROSS APPLY statement – it will connect all split values to the original row):

SELECT Country, S as FirstName FROM #Employees CROSS APPLY Split(',', FirstNames)

The result is

Country FirstName
UK      Anne
UK      Michael
UK      Robert
UK      Steven
USA     Andrew
USA     Janet
USA     Laura
USA     Margaret
USA     Nancy

One possible cause for this – your application is using Application Pool with 32bit mode enabled. If so – disable it or switch to a different application pool. Chances are this will fix the above issue.