Hi kankon,

Check this sample. now take its reference.

HTML

<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<link href="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/css/bootstrap.min.css"
    rel="stylesheet" type="text/css" />
<script type="text/javascript" src="http://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.0.3/js/bootstrap.min.js"></script>
<link href="http://cdn.rawgit.com/davidstutz/bootstrap-multiselect/master/dist/css/bootstrap-multiselect.css"
    rel="stylesheet" type="text/css" />
<script src="http://cdn.rawgit.com/davidstutz/bootstrap-multiselect/master/dist/js/bootstrap-multiselect.js"
    type="text/javascript"></script>
<script type="text/javascript">
    $(document).ready(function () {
        $('#ddlCountries').multiselect({
            checkboxName: function (option) {
                var $optgroup = $(option).closest('optgroup');
                if ($optgroup.id == 'checkboxName-1') {
                    return 'group1[]';
                }
                else {
                    return 'group2[]';
                }
            }
        });
    });
</script>
<div class="form-group">
    <label class="col-sm-2 control-label">
        Multiselect</label>
    <div class="col-sm-10">
        <select id="ddlCountries" name="multiselect[]" multiple="multiple" required>
            <optgroup label="كهرباء" id="checkboxName-1">
                <option value="Argentina">مهندس كهرباء</option>
                <option value="Austria">اشرافي/ مساعد مهندس كهرباء</option>
                <option value="Belgium">فني كهرباء</option>
            </optgroup>
            <optgroup label="مدني" id="checkboxName-2">
                <option value="Brazil">مهندس مدني</option>
                <option value="Canada">اشرافي/ مساعد مهندس مدني</option>
                <option value="Denmark">فني مدني</option>
            </optgroup>
            <optgroup label="ميكاكنيك" id="checkboxName-3">
                <option value="Finland">مهندس ميكانيك</option>
                <option value="France">اشرافي/ مساعد مهندس ميكانيك</option>
                <option value="Germany">فني ميكاكنيك</option>
            </optgroup>
            <optgroup label="زراعة / نظافة / خدمات فندقية" id="checkboxName-4">
                <option value="Ireland">مهندس زراعة / نظافة / خدمات فندقية</option>
                <option value="Italy">اشرافي/ مساعد مهندس زراعة / نظافة / خدمات فندقية</option>
                <option value="Mexico">فني زراعة / نظافة / خدمات فندقية</option>
            </optgroup>
            <optgroup label="حاسوب / الكترونيات / اتصالات" id="checkboxName-5">
                <option value="Norway">مهندس حاسوب / الكترونيات / اتصالات</option>
                <option value="Poland">اشرافي/ مساعد مهندس حاسوب / الكترونيات / اتصالات</option>
                <option value="Portugal">فني حاسوب / الكترونيات / اتصالات</option>
            </optgroup>
        </select>
    </div>
</div>
<div class="form-group">
    <div class="col-sm-offset-2 col-sm-10">
        <asp:Button ID="btnSubmit" Text="Submit" runat="server" OnClick="OnSubmit" />
    </div>
</div>
<br />
<rsweb:ReportViewer ID="ReportViewer1" runat="server">
</rsweb:ReportViewer>
<hr />
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>

Namespaces

C#

using System.Configuration;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data.SqlClient

Code

C#

private void BindReport(string query)
{
    ReportViewer1.ProcessingMode = ProcessingMode.Local;
    ReportViewer1.LocalReport.ReportPath = Server.MapPath("~/Report.rdlc");
    Customers dsCustomers = GetData(query);
    ReportDataSource datasource = new ReportDataSource("DataSet1", dsCustomers.Tables["Customers"]);
    ReportViewer1.LocalReport.DataSources.Clear();
    ReportViewer1.LocalReport.DataSources.Add(datasource);
}

protected void OnSubmit(object sender, EventArgs e)
{
    string query = "SELECT CustomerID,ContactName,City,Country FROM Customers";
    string condition = string.Empty;

    foreach (string item in Request.Form["multiselect[]"].Split(','))
    {
        condition += string.Format("'{0}',", item);
    }

    if (!string.IsNullOrEmpty(condition))
    {
        condition = string.Format(" WHERE Country IN ({0})", condition.Substring(0, condition.Length - 1));
    }
    this.BindReport(query + condition);
}

private Customers GetData(string query)
{
    string conString = ConfigurationManager.ConnectionStrings["NORTHWINDConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                using (Customers dsCustomers = new Customers())
                {
                    sda.Fill(dsCustomers, "Customers");
                    return dsCustomers;
                }
            }
        }
    }
}

VB.Net

Private Sub BindReport(ByVal query As String)
    ReportViewer1.ProcessingMode = ProcessingMode.Local
    ReportViewer1.LocalReport.ReportPath = Server.MapPath("~/Report.rdlc")
    Dim dsCustomers As Customers = GetData(query)
    Dim datasource As ReportDataSource = New ReportDataSource("DataSet1", dsCustomers.Tables("Customers"))
    ReportViewer1.LocalReport.DataSources.Clear()
    ReportViewer1.LocalReport.DataSources.Add(datasource)
End Sub

Protected Sub OnSubmit(ByVal sender As Object, ByVal e As EventArgs)
    Dim query As String = "SELECT CustomerID,ContactName,City,Country FROM Customers"
    Dim condition As String = String.Empty
    For Each item As String In Request.Form("multiselect[]").Split(","c)
        condition += String.Format("'{0}',", item)
    Next
    If Not String.IsNullOrEmpty(condition) Then
        condition = String.Format(" WHERE Country IN ({0})", condition.Substring(0, condition.Length - 1))
    End If
    Me.BindReport(query & condition)
End Sub

Private Function GetData(ByVal query As String) As Customers
    Dim conString As String = ConfigurationManager.ConnectionStrings("NORTHWINDConnectionString").ConnectionString
    Using con As SqlConnection = New SqlConnection(conString)
        Using cmd As SqlCommand = New SqlCommand(query, con)
            Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                Using dsCustomers As Customers = New Customers()
                    sda.Fill(dsCustomers, "Customers")
                    Return dsCustomers
                End Using
            End Using
        End Using
    End Using
End Function

Screenshot