| r.a.d.controls version |
Q3 2006 (RAD GRID) |
| .NET version |
2.0.50727 |
| Visual Studio version |
2005 |
| programming language |
VB.NET |
| browser support |
all browsers supported by r.a.d.controls |
PROJECT DESCRIPTION It is sometimes necessary to swap raw grid cell data for something else - the template column functionality that comes built into r.a.d. grid enables you to take the first step to achieving this.
But simplying having a templated column on its own is not enough - there are many occassions were it is necessary to have some sort of data-bound functionality associated with the templated-column or render out the templated-column based on underlying raw data.
In this example, we demonstrate a simple message system using the r.a.d. grid - its purpose is to simply display messages to the end-user.
NB: The actual functionality for this system has been stripped out as it is sensitive to client-projects.
In the message system we use a simple table in Access 2003 to store our messages using the following schema:
- ID
- CreatedOn
- From
- Subject
- IsRead
When rendered onto the grid, we do not want to dislay the
ID or
IsRead columns from the schema - however we want to add in two templated-columns -
Select and
Status. For the purposes of this code-sample, we ignore the
Select templated-column.
The
Status templated-column simply contains the Image Control, supplied within the .NET System.Web DLL/namespace.
Instead of displaying the checkbox/boolean column IsRead, we are going to use the
Status columns'
Image control to render one of two possible images depending on the value contained in the
IsRead column during the databinding event cycle - as with all messages, we have two possible image states,
read (TRUE) and
unread (FALSE).
Next we simply handle the r.a.d. grids'
ItemDataBound event in the code-behind file:
| Protected Sub RadGrid1_ItemDataBound(ByVal sender As Object, ByVal e As Telerik.WebControls.GridItemEventArgs) Handles RadGrid1.ItemDataBound |
| 'Declare variables for use and default them to null |
| Dim dataItem As GridDataItem = Nothing |
| Dim data As Data.DataRowView = Nothing |
| Dim img As Image = Nothing |
| Dim value As Boolean = Nothing |
| Try |
| 'Check that we are potentially referencing a |
| ' GridDataItem object: |
| If TypeOf e.Item Is GridDataItem Then |
| |
| 'Using the event agruments, we obtain a reference to the |
| ' current Grid DataItem: |
| dataItem = CType(e.Item, GridDataItem) |
| |
| 'From the DataItem we get a reference to the databinding object |
| 'which is a DataRowView object: |
| data = CType(dataItem.DataItem, Data.DataRowView) |
| |
| 'Next, we get a reference to the Image control contained |
| 'within the current Grid DataItem: |
| img = CType(dataItem("Status").Controls(1), Image) |
| |
| 'Last, but not least, we find out the value |
| ' of the IsRead row item of type boolean: |
| value = CType(data.Row.Item("IsRead"), Boolean) |
| |
| 'IF the value is TRUE then use the Read image url and tooltip, |
| 'OTHERWISE, use the Unread image url and tooltip: |
| If value Then |
| img.ImageUrl = "~/res/pics/MailItem_Read_16.png" |
| img.ToolTip = "This message has been read." |
| Else |
| img.ImageUrl = "~/res/pics/MailItem_Unread_16.png" |
| img.ToolTip = "This message has not been read." |
| End If |
| |
| End If |
| Catch ex As Exception |
| 'The exception is ignored |
| Finally |
| 'Finally, destroy used variables |
| dataItem = Nothing |
| data = Nothing |
| img = Nothing |
| value = Nothing |
| End Try |
| End Sub |
Now we have a templated-column that can be custom-rendered with whatever we want!
Hope this is of help to someone.