Community discussion forum
Building a Full-Featured Custom DataGrid Control
-
This thread is for discussions of Building a Full-Featured Custom DataGrid Control.
-
Advertisement
Simply the fastest line-level profiler for .NET ever
“The low overhead means it has minimal impact on the execution of my program”
Mark Everest, Development Team Leader, Renault F1 Team Ltd.Try out the new ANTS Profiler 4 for yourself. Download your 14-day trial now
-
Hey folks,
Here's one quick and easy way to add a background image to your Datagrid header, to give it a more fuller look. The code to do this is:
Code: if (elemType == ListItemType.Header ) {
e.Item.Style["background-image"] = "url(yourimage.jpg)";
}
Simply add this to my article's "myCustDG.cs" source file code in the "GridCreated" method found at the end, recompile the source code to get your "myCustDG.dll" and you're done.
Even easier is my other forum post "Custom DG Control w/ Dual Paging, Drag & Drop/Sort" that has this incorporated into it and a whole lot more and you can download the code with all the enhancements here -> http://members.aol.com/dmarko1/dnjcode/CustDGDualPagingDragDrop_Sort.zip
-Jimmy Markatos -
Hi all,
I’ve added a newly enhanced version of my Custom Datagrid that adds some cool features and functionality including drag & drop columns that was incorporated from the wonderful article Extend the ASP.NET Datagrid with Client-side Behaviors by Dino Esposito found in the January 2004 issue of MSDN Magazine.
I merged the code and functionality into the class assembly instead of the two found in the article. So in turn, you now really end with an awesome fully featured custom Datagrid control!
The features are:
1) Custom Paging taken from my article - Custom ASP.NET DataGrid Paging With Exact Count , alongside the conventional Datagrid paging setup.
2) Drag & Drop Columns and Sorting from Dino Esposito's article
3) Adding Background Image to Datagrid Header
4) OnMouseover Datagrid Row Highlighting
The only difference from this and my original article and code from "Building a Full-Featured Custom Datagrid Control" aside from the aforementioned, is in the code-behind setup. In this case, the dll class contains the drag & drop code and the Datagrid class only. My code-behind page inherits this and contains all of the remaining code.
Be also sure to check out this article here on developerfusion.com where I have listed four additional Datagrid enhancements that you could incorporate into this Datagrid.
Download the code here -> http://members.aol.com/dmarko1/dnjcode/CustDGDualPagingDragDrop_Sort.zip
And feel free to send me an email and tell me what you think -- dmarko1@aol.com
-Jimmy Markatos -
Doing someting similar to the code in the posting for "Building a Full-Featured Custom DataGrid Control" using datagrids and having a duece of a time getting past one problem.
The error encountered is System.InvalidCastException: Specified cast is not valid. I'm using the same code as up above for setting up the databinding for an item template in a datagrid. If I use a control file I have no problems with binding the data (from my SQL Server database). But for some reason I can't assign the databinding using a code behind file . Here's the code, just like up above as far as I can tell.
LiteralControl lc = (LiteralControl) sender;
DataGridItem container = (DataGridItem) lc.NamingContainer;
lc.Text = ((DataRowView) container.DataItem) [columnName].ToString();
Again, I have no problems binding to my itemtemplate column using other methods, so I'm wrather sure it's not a data issue. I have seen mention on MSDN of this type of problem possibly being related to control tree hierarchy being re-ordered at this address http://support.microsoft.com/default.aspx?scid=kb;en-us;Q327287 but I couldn't see how to fix it from what they gave as a solution. Their solution, to save you the trip, is this:
"Make sure that the control tree is re-created on postback in the same order that it was saved at the end of the previous request." My depth of .net knowledge doesn't go that deep.
Any ideas?
Thanks.
Stack trace is here.
[InvalidCastException: Specified cast is not valid.]
DataGridTemplate.OnDataBinding(Object sender, EventArgs e) +13
System.Web.UI.Control.OnDataBinding(EventArgs e) +66
System.Web.UI.Control.DataBind() +26
System.Web.UI.Control.DataBind() +86
System.Web.UI.Control.DataBind() +86
System.Web.UI.WebControls.DataGrid.CreateItem(Int32 itemIndex, Int32 dataSourceIndex, ListItemType itemType, Boolean dataBind, Object dataItem, DataGridColumn[] columns, TableRowCollection rows, PagedDataSource pagedDataSource) +169
System.Web.UI.WebControls.DataGrid.CreateControlHierarchy(Boolean useDataSource) +1411
System.Web.UI.WebControls.BaseDataList.OnDataBinding(EventArgs e) +49
System.Web.UI.WebControls.BaseDataList.DataBind() +23
Rock.BudgetDataGrid.datagridSetup(DataGrid datagrid) +914
ASP.CreateProfilePage4aspx.PageLoad(Object sender, EventArgs e) in \CreateProfilePage4.aspx:28
System.Web.UI.Control.OnLoad(EventArgs e) +67
System.Web.UI.Control.LoadRecursive() +35
System.Web.UI.Page.ProcessRequestMain() +750 -
I wrote my own custom datagrid a short time ago, and included code that automatically handled the pageindexchanged and itemdatabound events. The upshot was that I could not get the code to run unless I re-bound the control on every page load.
Is this normal?
Conventional datagrids do not require this. What could I have been doing wrong?
What are the issues with auto handling events with custom controls?
many thanks
Sean. -
In order for those events to fire, you have to re-create the same controls when the page is reloaded. The DataGrid does this by using it's ViewState to restore the data it was originally bound to, and hence recreating all the rows in the table. You'd therefore have to do a similar trick of storing the data in the ViewState, and rebinding to that if DataBind() isn't called.
-
Will take another look.
Many thanks for your reply.
Sean. -
Cool, thanks. Glad to see it's helped you out.
-
Your Datagrid is very useful. I have built a custom DG with paging set for Months (Jan-Dec) which serves up the sales for the month selected in the Pager Tab. I have also enabled both Header Editing and Freezing Header as you scroll. What I have not been able to do is to allow the Pager control to freeze in a similar manner as you scroll- the goal being to have the Header and Pager Tabs always visible so you don't have to go back to the top to change selection or remember what the data is in which column. In general, I have not been able to apply any formatting using CSS to the pager at all. Any help would be appreciated.
Thanks! -
Thanks stevemets,
What you need is a custom pager control to give you the ability to provide fixed paging. I believe what you're looking for can be found here - Creating a Pager Control for ASP.NET by Dino Esposito.
Hope this helps! -
Thanks- this seems to be a different approach. I haven't looked at it in detail, but am interested. It's interesting that the DataGrid with Month Pager Tabs was based on an article Dino wrote in ASP.Net Pro, and he also wrote the other 2 on editing the header, which I got to work, and on freezing the header, which I could not get to work (all of his samples in ASP.Net Pro are in C#, and I am still using VB, so I'm forced to use a translator which doesn't alway work. They have just changed their policy to include both C# and VB, which is the best way to learn either in my opinion).
Thanks for the help. Do you know of any examples where the Pager can be manipulated with CSS? -
Sure. You'll notice in my article's datagrid enhancements section How to customize the Datagrid pager, I show one way of manipulating the pager to which CSS could easily be added.
Furthermore, in the article's forum post I offer an improved version of my custom datagrid control, where I have added onmouseover rowhighlighting which further demonstrates CSS enhancement.
Essentially, in modifying any elements of the datagrid, you’ll need to work with the grid’s OnItemCreated or OnItemDataBound methods to include any grid manipulations.
Example:
Your stylesheet:
Code: <style>
.DGPager {font-family: garamond; font-size:16px;}
.DGPager a:link {font-size:16px; color:#0000FF;}
.DGPager a:visited {font-size:16px; color:#C0C0C0;}
.DGPager a:hover {font-size:16px; color:#FF0000;}
</style>
Next, add the event handler to your datagrid to call the method
Code: OnItemCreated="Item_Created"
And in the OnItemCreated method or in my article's GridCreated method, you add the following code in your code-behind or in your main page which determines you want to deal with the datagrid’s pager. The same goes for the header:
Code: if (elemType == ListItemType.Pager) {
e.Item.Cells[0].Attributes.Add("class","DGPager");
}
and for you in VB:
Code: If (e.Item.ItemType = ListItemType.Pager) Then
e.Item.Cells(0).Attributes.Add("class","DGPager")
End If
That’s it.
-Jimmy Markatos -
Excellent!
-
Glad to help!
-
I am dynamically creating/adding template columns to my datagrid. (implementing ITemplate interface).
However, I am unable to set the width of this dynamically added column.
any ideas?
Many thanks,
anabhra -
Sure, just add your datagrid column modifications in the ItemCreated event handler.
Ex. in Pixels:
Code: 'VB
Private Sub GridCreated (ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles GridCreated
e.Item.Cells(0).Width = New Unit (100, UnitType.Pixel)
e.Item.Cells(1).Width = New Unit (75, UnitType.Pixel)
End Sub
//C#
private void GridCreated (object sender, DataGridItemEventArgs e)
{
e.Item.Cells[0].Width = new Unit (100, UnitType.Pixel);
e.Item.Cells[1].Width = new Unit (75, UnitType.Pixel);
}
Furthermore, you can accomodate other Unit structures such as Percentage.
Ex. in Percentage:
Code: 'VB
Private Sub GridCreated (ByVal sender As Object, ByVal e As System.Web.UI.WebControls.DataGridItemEventArgs) Handles GridCreated
e.Item.Cells(0).Width = New Unit (50, UnitType.Percentage)
e.Item.Cells(1).Width = New Unit (25, UnitType.Percentage)
End Sub
//C#
private void GridCreated (object sender, DataGridItemEventArgs e)
{
e.Item.Cells[0].Width = new Unit (50, UnitType.Percentage);
e.Item.Cells[1].Width = new Unit (25, UnitType.Percentage);
}
Hope this helps.
- Jimmy Markatos -
thanks a lot.
your suggestion will work.
I just solved my problem by setting the header template and itemtemplate widths. I had the grid in a div and that is why I could not see the widths. Once I set the table layout of the grid to fixed, I saw the columns being sized.
again, many thanks for your interest. -
You're welcome. Glad to help!
-
I have one more question:
When using template columns dynamically, are they stored in the view state?
It seems not but I would like to have them as I have editable text boxes in the template columns that user enters data in...
Many thanks,
anabhra -
Yes, becuase by default all data within a DataSet is typically persisted in ViewState. Have you explcitly disabled Page ViewState? I don't see how your dynamically sized columns would reset themselves.
At any rate, try enabling the DataGrid's DataGrid.EnableViewState property to true to maintains its state across HTTP requests.
Furthermore, you can ideally stored any values you require to be persistant by storing those values in Session State.
This should take care of it.
- Jimmy Markatos -
I read this article on msdn:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemwebuiwebcontrolsdatagridcolumncollectionclasstopic.asp
It seems to say that derived coumns (from say itemtemplate) that are added at run time are not saved to view state.
They suggest having all needed cols and set visible attribute of those not needed for display to be set to false.
I do have the EnableViewState=true (I think that is the default) on the page and grid. I have 2 other grids that do maintain the state...
-anabhra -
Right, I misunderstood you, as I was referring to DataSet data and I simply specified if you explicitly disabled view state, as yes, of course, true is the default. Now if you utilize what else I've mentioned then you shouldn’t have any issues.
Also, I don't know what you mean with 2 other grids that maintain state. Are they all the same with dynamic item templates and all? As I can’t see your code I don’t know what you may have overlooked or otherwise.
Therefore, employ the Page_Init method to help with this, but ultimately whenever something doesn't hold state by normal means as you would’ve hope it would then make use of view state.
Hope this helps. -
Hi all,
I just re-added the forum post containing the new version of my article code. I just thought it easier to repost it again, since I find people requesting this and since the topics become hidden after a while, it won't show up unless you select all topics.
Anyway, here is the link:
Custom DG Ctrl w/ Dual Paging, Drag&Drop/Sort DL code forum post
-Jimmy Markatos -
I'm having the same problem. Please let me know if you find anything.
-
how can i implement sorting for all the column in this sample?
-
Hi,
You can implement one way as found in my other article here on DF - Dynamic Column Sorting and Paging in ASP.NET or you can download the upgraded version of my custom datagrid control with drag and drop columns and sorting.
-Jimmy Markatos -
I am having a datagrid where i am binding all boundcolumns from dataset and along with it i am having 2 templates , one is label and another checkbox . these two controls are bound to datagrid using itemplate class (i.e. dynamically) . when i am attaching checkbox and allocating event checkedchanged , its not getting fired and also i am unable to get how many checkbox are clicked (if autopostback=false) . if autopostback is true then datagrid is not displayed but if i again bind datagrid with all bouncontrols usinf sessions then i get same old datagrid but all checkbox are false .
I hope i am clear with my problem . please help me in getting event fired for checkbox and also getting count for number of check box clicked .
Thanks in advance,
Rujuta -
There will be some 20 questions and for each question there will be 4 choices.what i want to do is to select multiple answers by clicking the checkbox. i m using asp.net,vb.net
pls help me
we have written the code using radio button for selecting single item.but we want to replace it with checkbox to select multiple items. the code using radio button is given below .pls correct it with checkbox
Imports System.Data
Imports System.Data.SqlClient
Imports ELearning.LAIDBC
Public Class Test
Inherits System.Web.UI.Page
Public ds As New DataSet()
Public ds1 As New DataSet()
Public ds2 As New DataSet()
Public Score, Answered As Integer
Protected WithEvents txtNoOfqns As System.Web.UI.WebControls.TextBoxRegion " Web Form Designer Generated Code "
'This call is required by the Web Form Designer.
<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
End Sub
Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init
'CODEGEN: This method call is required by the Web Form Designer
'Do not modify it using the code editor.
InitializeComponent()
End Sub
Protected WithEvents lblCourse As System.Web.UI.WebControls.Label
Protected WithEvents lblCourseName As System.Web.UI.WebControls.Label
Protected WithEvents lblNoOfQuestions As System.Web.UI.WebControls.Label
Protected WithEvents lblDurationInMinutes As System.Web.UI.WebControls.Label
Protected WithEvents txtduration As System.Web.UI.WebControls.TextBox
Protected WithEvents lblTimeLeft As System.Web.UI.WebControls.Label
Protected WithEvents lblAnswered As System.Web.UI.WebControls.Label
Protected WithEvents txtanswered As System.Web.UI.WebControls.TextBox
Protected WithEvents DataGrid1 As System.Web.UI.WebControls.DataGrid
Protected WithEvents submitbtn As System.Web.UI.WebControls.Button
Protected WithEvents lab2 As System.Web.UI.WebControls.Label
Protected WithEvents Lab4 As System.Web.UI.WebControls.Label
Protected WithEvents Label2 As System.Web.UI.WebControls.Label
Protected WithEvents lab1 As System.Web.UI.WebControls.Label
Protected WithEvents txtans As System.Web.UI.WebControls.TextBoxEnd Region
Private ConDB As New ELearning.LAIDBC()
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
If Session("Log") = Nothing Then
Response.Redirect("frmLogin.aspx")
End If
If Not IsPostBack Then
Try
Session("Course") = Session("URL2")
Session("Id") = "reshm-001"
Session("CandId") = "00000001"
'Response.Write(Session("Id"))
'Response.End()
Session("TotScore") = Nothing
Dim count1, str11 As String
ds1 = New DataSet()
ConDB.OpenConnection()
ds1 = ConDB.ExecuteSPReturnDS("ELSExecuteQuery", "select count(fUserId) from tblScore where fUserId='" & (Session("CandId")) & "' and fcourseid='" & Session("Id") & "' ")
ConDB.CloseConnection()
count1 = ds1.Tables(0).Rows(0)(0)
str11 = "select count(fUserId) from tblScore where fUserId='" & (Session("CandId")) & "' and fcourseid='" & Session("Id") & "'"
'Response.Write(str11)
'Response.End()
If count1 < 3 Then
' Response.Write(str11 & "," & count1)
ds2 = New DataSet()
Dim count2 As Integer
ConDB.OpenConnection()
ds2 = ConDB.ExecuteSPReturnDS("ELSExecuteQuery", "select count(fUserId) from tblScore where fUserId='" & (Session("CandId")) & "' and fresult='P'")
count2 = ds2.Tables(0).Rows(0)(0)
Response.Write(count2)
ConDB.CloseConnection()
If count2 > 0 Then
Session("msg") = "You have already passed for the test"
Response.Redirect("frmChance.aspx")
Else
Dim qrstr As String
Dim NoOfQuestionsToDisplay As Integer
Dim Mstring As String
Dim TotalNoOfQuestions As Integer
courseidselect()
Try
NoOfQuestionsToDisplay = txtNoOfqns.Text
Session("NoOfQuestionsToDisplay ") = txtNoOfqns.Text
ds = New DataSet()
ConDB.OpenConnection()
ds = ConDB.ExecuteSPReturnDS("ELSExecuteQuery", "select count(*) from tblQuestion where f_CourseId='" & Session("Id") & "'")
ConDB.CloseConnection()
TotalNoOfQuestions = ds.Tables(0).Rows(0)(0)
Session("TotQns") = TotalNoOfQuestions
Catch ex As Exception
R -
I have created a Custom control using your article but i am having problem in sorting and update
as i use a class which implements itemplate interface for this and create the function for update and
sorting in same class.when i click on them the changes are made in database and dataset but they does not display on page and display on second click as these function are called in last i.e the getdatagrid() method is not called after them hence no changes are viewed.Please help me to resolve this problem.Can i use ipostbackdatahandler.
Thanks in Advance -
Quote: [1]Posted by taxiturner on 3 May 2005 10:25 PM[/1]
LiteralControl lc = (LiteralControl) sender;
DataGridItem container = (DataGridItem) lc.NamingContainer;
lc.Text = ((DataRowView) container.DataItem) [columnName].ToString();
I believe that "container" is your problem.
try:
lc.Text = ((DataRowView)e.Item.DataItem)[columnName].ToString();
Now, if someone could just tell me how to cast a DataGridItemCollection as a TableRowCollection so that I don't get this error, that would be helpful. -
I build my own custom datagrid control using the code from your site.
I used this control as a reference in another aspx page at you have mentioned in your article.
I have 400 total number of records and my page count is 5. I wrote a stored procedure which will fetch 10 records each time for custom paging.
When I click on ellipse after 5 it shoud page 6 to 10 but they link to first set of pages. So when I click on 6 it takes me to page 1 and so on. I am unable to navigate to more than 5 pages....
Please Let me know... -
Hi,
I am building a ASP .NET composite control containing a datagrid during which I am
finding a problem while paging of the grid.
The problem is for example if I am having three pages to be displayed in the
datagrid, I have set the paging mode to be numeric.Now I am going to have
1,2,3 for navigation.
All navigations are working perfectly but when I go back to page 1 after page 2
or 3, the PageIndexChanged event is not triggered and I happen to see only the
information of previous page (i.e page 2 or page 3).
Thanks in Advance
Ashish
Post a reply
Related discussion
-
increase maxRequestLength in httpRuntime of Web.Config
by bussureddy82 (0 replies)
-
How to modify desktop app to work from many computers
by systeko (0 replies)
-
how to select item to datagrid from textbox
by chandradev1 (50 replies)
-
Problem after strong naming an assembly
by rinkurathor1 (0 replies)
-
Very slow inserts using SqlCommand.ExecuteNonQuery()
by porchelvi (1 replies)
Related articles
Quick links
Recent activity
- Rajasekhar Reddy replied to increase maxRequestLength i...
- Cason Lopez replied to Need suggestions......
- Subhadip Roy replied to help me in file handling in...
- Maneesh Jain replied to Complete portal of VOIP pro...
- Scot In replied to I don't want the Excel work...
- Luc Joly replied to Help with datagridview
Enter your message below
Sign in or Join us (it's free).