DropDown List With Multiple Selection Option in SharePoint 2010

Introduction

This article shows how to create a DropDown list with multiple selection options. This custom control DropDown allows multiple selections. In an ASP.Net DropDown we select only one option at a time.

DropDown with multiple selections Screen Shot

Aspx code

.DivClose

{

display: none;

position: absolute;

width: 150px;

height: 220px;

border-style: solid;

border-color: Gray;

border-width: 1px;

background-color: #F0FFFF;

}

.LabelClose

{

vertical-align: text-top;

position: absolute;

bottom: 0px;

font-family: Verdana;

}

.DivCheckBoxList

{

display: none;

background-color: White;

width: 150px;

position: absolute;

height: 200px;

overflow-y: auto;

overflow-x: hidden;

border-style: solid;

border-color: Gray;

border-width: 1px;

width: 150px;

}

.CheckBoxList

{

position: relative;

width: 150px;

height: 10px;

overflow: scroll;

font-size: small;

}

.Maintitle

{

text-align: left;

margin: 0em;

color: #00008B;

font-size: large;

padding-bottom: 16px;

border-bottom: 2px solid #A9A9A9;

margin-bottom: 10px;

white-space: nowrap;

}

.headers

{

text-align: left;

padding-right: 10px;

}

.numbers

{

text-align: right;

padding-right: 12px;

}

.textData

{

text-align: left;

padding-right: 10px;

}

.numbersHeader

{

width: 80px;

}

.numbersfooter

{

background-color: #d2d0d0;

color: #000000;

}

.SGridView

{

width: 100%;

}

.style1

{

height: 30px;

}

</style>

<asp:Literal ID="LtrMessage" runat="server"></asp:Literal>

<tr>

</td>

<td>

<div id="divCustomCheckBoxList" runat="server" onmouseover="clearTimeout(timoutID);"

onmouseout="timoutID = setTimeout('HideMList()', 750);">

<table>

<tr>

<input id="txtSelectedMLValues" type="text" readonly="readonly" onclick="ShowMList()"

style="width: 150px;" runat="server" />

</td>

</td>

</tr>

<tr>

<div>

</label>

</div>

<asp:UpdatePanel ID="UpdatePanel11" runat="server">

<asp:CheckBox ID="CheckBoxList1" runat="server" Text="All" AutoPostBack="true" OnCheckedChanged="CheckBoxList1_CheckedChanged">

</asp:CheckBox>

<asp:CheckBoxList ID="lstMultipleValues" runat="server" Width="250px" CssClass="CheckBoxList">

</asp:CheckBoxList>

</ContentTemplate>

</asp:UpdatePanel>

</div>

</td>

<td>

</td>

</tr>

</table>

<br />

<div>

</div>

<div>

var timoutID;

//This function shows the checkboxlist

function ShowMList() {

var divRef = document.getElementById("<%=divCheckBoxList.ClientID%>");

divRef.style.display = "block";

var divRefC = document.getElementById("<%=divCheckBoxListClose.ClientID%>");

divRefC.style.display = "block";

}

//This function hides the checkboxlist

function HideMList() {

document.getElementById("<%=divCheckBoxList.ClientID%>").style.display = "none";

document.getElementById("<%=divCheckBoxListClose.ClientID%>").style.display = "none";

}

var cblstTable;

var checkBoxPrefix;

var noOfOptions;

var selectedText

function FindSelectedItems(sender, textBoxID) {

cblstTable = document.getElementById(sender.id);

var flagUnchecked = 0;

var flaChecked = 0;

checkBoxPrefix = sender.id + "_";

noOfOptions = cblstTable.rows.length;

selectedText = "";

for (i = 0; i < noOfOptions; ++i) {

if (document.getElementById(checkBoxPrefix + i).checked) {

flag = 1;

if (selectedText == "")

selectedText = document.getElementById

(checkBoxPrefix + i).parentNode.innerText;

else

selectedText = selectedText + "," +

document.getElementById(checkBoxPrefix + i).parentNode.innerText;

}

for (i = 0; i < noOfOptions; ++i) {

if (document.getElementById(checkBoxPrefix + i).checked == false) {

document.getElementById("<%=CheckBoxList1.ClientID%>").checked = false;

}

if (document.getElementById(checkBoxPrefix + i).checked == true) {

flagUnchecked = 1;

flaChecked = flaChecked + 1;

}

document.getElementById(textBoxID.id).value = selectedText;

if (flagUnchecked == 0) {

document.getElementById(textBoxID.id).value = "Select City";

}

if (flaChecked == noOfOptions) {

document.getElementById("<%=CheckBoxList1.ClientID%>").checked = true;

document.getElementById(textBoxID.id).value = "All City";

}

function FindAllRepMgr(sender, textBoxID) {

if (document.getElementById("<%=CheckBoxList1.ClientID%>").checked == true) {

for (i = 0; i < noOfOptions; ++i) {

var raw = document.getElementById(checkBoxPrefix + i).rawValue = null;

var raw1 = document.getElementById(checkBoxPrefix + i).checked = true;

document.getElementById(checkBoxPrefix + i).checked == true;

}

document.getElementById(textBoxID.id).value = "All City";

}

if (document.getElementById("<%=CheckBoxList1.ClientID%>").checked == false) {

for (i = 0; i < noOfOptions; ++i) {

var raw = document.getElementById(checkBoxPrefix + i).rawValue = null;

var raw1 = document.getElementById(checkBoxPrefix + i).checked = false;

document.getElementById(checkBoxPrefix + i).checked == false;

}

document.getElementById(textBoxID.id).value = "Select City";

}

</script>

</div>

C#: Cs.code