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Multi-select ASP.NET datagrid

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7 Mar 20042 min read 677.1K   17.6K   165   127
How to extend ASP.NET datagrid for multi-selection of data rows.

Sample image

Introduction

ASP.NET datagrid is a very powerful and flexible control, however some features like multi-select is not natively available. This article shows how easily this functionality can be achieved with a few simple tricks.

Background

One of the projects I was working on had a User Inteface requirement for multi-selection of grid rows. User wanted Hotmail or Yahoo style multi-selection facility along with highlighting the selection (hard part).

Using the code

After testing and applying some javascript and grid related coding techinque, I came up with the following working solution.

  • Add Template column for CHECKBOXES for selection (Hotmail/Yahoo style)
  • Add client-side onclick() and javascript for checkboxes, to highlight and mark checked rows.
  • Add server side CheckedChanged() event for preserving highlights. [because everytime on postback datagrid resets colors for the selection]
ASP.NET
<Columns>
 <asp:TemplateColumn>
  <HeaderTemplate>
   <asp:CheckBox id="chkAll" 
      onclick="javascript:SelectAllCheckboxes(this);" runat="server" 
    AutoPostBack="false" ToolTip="Select/Deselect All" />
  </HeaderTemplate>
  <ItemTemplate> 
    <asp:CheckBox id="chkSelect" onclick="javascript:HighlightRow(this);"
        runat="server"OnCheckedChanged= "grdEmployees_CheckedChanged" 
        AutoPostBack="false" />
  </ItemTemplate> 
 </asp:TemplateColumn> 
</Columns>

SelectAllCheckBoxes()

This function is used to have Hotmail style selection, it iterate through every check box on the form and then selects/deselects the checkboxes.

HighlightRow()

The only challenge left was to highlight and un-highlight the rows on selection and deselection. For which, I used

HighlightRow() 
function, please note one very important thing when using <asp:CheckBox> control. It surrounds <SPAN> tags around CHECKBOX and therfore in javascript you have to get the children of the <SPAN> tag.

JavaScript
//-------------------------------------------------------------
// Select all the checkboxes (Hotmail style)
//-------------------------------------------------------------
function SelectAllCheckboxes(spanChk){

// Added as ASPX uses SPAN for checkbox
var oItem = spanChk.children;
var theBox=oItem.item(0)
xState=theBox.checked;

    elm=theBox.form.elements;
    for(i=0;i<elm.length;i++)
    if(elm[i].type=="checkbox" && elm[i].id!=theBox.id)
        {
        //elm[i].click();
        if(elm[i].checked!=xState)
        elm[i].click();
        //elm[i].checked=xState;
        }
}

//-------------------------------------------------------------
//----Select highlish rows when the checkboxes are selected
//
// Note: The colors are hardcoded, however you can use
//       RegisterClientScript blocks methods to use Grid's
//       ItemTemplates and SelectTemplates colors.
//         for ex: grdEmployees.ItemStyle.BackColor OR
//                 grdEmployees.SelectedItemStyle.BackColor
//-------------------------------------------------------------
function HighlightRow(chkB)    {
var oItem = chkB.children;
xState=oItem.item(0).checked;
if(xState)
    {chkB.parentElement.parentElement.style.backgroundColor='lightcoral';
       // grdEmployees.SelectedItemStyle.BackColor
     chkB.parentElement.parentElement.style.color='white';
       // grdEmployees.SelectedItemStyle.ForeColor
    }else
    {chkB.parentElement.parentElement.style.backgroundColor='white';
         //grdEmployees.ItemStyle.BackColor
     chkB.parentElement.parentElement.style.color='black';
         //grdEmployees.ItemStyle.ForeColor
    }
}
// -->

This was the client side story. So far so good. One may argue why not use the plain simple HTML checkbox control? The answer is ASP.NET server control has a viewstate and therefore posting a page retains the rows selection.

Server Side

Now, On the server side we have to make sure the highlights are intact, because on every postback ASP.NET renders grid and loses the highlights. Following method is used for re-rendering the highlights.

VB.NET
Public Sub grdEmployees_CheckedChanged(ByVal sender As Object, _
    ByVal e As System.EventArgs)
  Dim chkTemp As CheckBox = CType(sender, CheckBox)

  Dim dgi As DataGridItem 

  dgi = CType(chkTemp.Parent.Parent, DataGridItem)
  If (chkTemp.Checked) Then 

    dgi.BackColor = grdEmployees.SelectedItemStyle.BackColor 
    dgi.ForeColor = grdEmployees.SelectedItemStyle.ForeColor
  Else 

    dgi.BackColor = grdEmployees.ItemStyle.BackColor
    dgi.ForeColor = grdEmployees.ItemStyle.ForeColor 
  End If
End Sub

Getting your selection

Its easy! Iterate through the DataGridItems collection and grab the checkbox [for ex. DemoGridItem.Cells(0).Controls(1)]. And verify its CHECKED property. Oh, also you can use DataKeyField of the dataset to grab specific datarows. Check out the attached code and you will love to find out how easy it is to multi-select rows.

Conclusion

Follow the downloaded code, you can simply use any SQL database. This is my very first article, hope .NET lovers would like it. Feedback is welcome.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


Written By
Web Developer
United States United States
Cranking code more than 12 years. Technical/Project lead/MCSD. Offered services to various industuries like S/W, Telecom, Publishing, Insurance etc.

When not on computer, I play/swim/read with my kids and help my better half (of course my lovely wife) to clean house. Solving challenging S/W problems is my passion. Hate non-productive meetings. Do lots of GOOGLE and Eat/Drink/Sleep around MSDN.

Comments and Discussions

 
GeneralMy vote of 5 Pin
Manoj Kumar Choubey7-Feb-12 19:30
professionalManoj Kumar Choubey7-Feb-12 19:30 
GeneralMy vote of 5 Pin
Member 782175621-Apr-11 10:23
Member 782175621-Apr-11 10:23 
GeneralMy vote of 1 Pin
badri vishal23-Nov-10 19:18
badri vishal23-Nov-10 19:18 
GeneralMy vote of 1 Pin
Dima Pasko27-Aug-09 11:49
Dima Pasko27-Aug-09 11:49 
GeneralMy vote of 1 Pin
Jitesh Sachdeva12-Jan-09 17:04
Jitesh Sachdeva12-Jan-09 17:04 
GeneralMultiSelect via Client-Side Pin
Todd Lucas1-Sep-06 12:31
Todd Lucas1-Sep-06 12:31 
GeneralRe: MultiSelect via Client-Side Pin
Patrick Olurotimi Ige19-Sep-06 14:44
Patrick Olurotimi Ige19-Sep-06 14:44 
NewsMultiple Gridviews or Checkbox columns Pin
McDude15-Jun-06 13:10
McDude15-Jun-06 13:10 
GeneralRe: Multiple Gridviews or Checkbox columns Pin
Code Buster10-Aug-06 19:36
Code Buster10-Aug-06 19:36 
Generalunselect check box based on others ckbx Pin
Jamshidi3-Mar-06 12:09
Jamshidi3-Mar-06 12:09 
GeneralCommand button in data Grid Pin
S.Das2-Mar-06 20:28
S.Das2-Mar-06 20:28 
GeneralJavascript Functions Pin
4-Sep-05 21:40
suss4-Sep-05 21:40 
GeneralRe: Javascript Functions Pin
enjoycrack5-Sep-05 0:12
enjoycrack5-Sep-05 0:12 
AnswerRe: Javascript Functions Pin
Sasi Atia12-Feb-06 20:52
Sasi Atia12-Feb-06 20:52 
GeneralRe: Javascript Functions Pin
hb3219-Mar-08 3:47
hb3219-Mar-08 3:47 
Generalc# version Pin
Loic Deniel23-Aug-05 22:16
Loic Deniel23-Aug-05 22:16 
GeneralRe: c# version Pin
Anonymous26-Oct-05 8:04
Anonymous26-Oct-05 8:04 
Questionhow to get cell Text when AutoGenerateColumns="false" Pin
torontomouse4-Aug-05 19:57
torontomouse4-Aug-05 19:57 
GeneralModified client script Pin
dpadevet21-Jul-05 3:26
dpadevet21-Jul-05 3:26 
GeneralRe: Modified client script Pin
htb huang19-Mar-07 12:32
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GeneralButton instead of CheckBox Pin
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GeneralMozilla Firefox Browers Pin
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GeneralRe: Mozilla Firefox Browers Pin
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Generalscript correction Pin
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