--- title: "Binding all college names to a college-dropdownlist based on data selected in another city-dropdownlist , both dropdownlists are placed inside the datalist" description: "Binding all college names to a college-dropdownlist based on data selected in another city-dropdownlist , both dropdownlists are placed inside the datalist" author: "Rashmi S" published: 2014-11-21 updated: 2014-11-22 canonical: https://www.mindstick.com/forum/12672/binding-all-college-names-to-a-college-dropdownlist-based-on-data-selected-in-another-city-dropdownlist-both-dropdownlists-are-placed-inside-the-datalist category: ".net" tags: ["dropdown"] reading_time: 7 minutes --- # Binding all college names to a college-dropdownlist based on data selected in another city-dropdownlist , both dropdownlists are placed inside the datalist [Binding](https://www.mindstick.com/blog/146/dynamic-binding-in-c-sharp) all college names to a college-[dropdownlist](https://www.mindstick.com/articles/324837/how-to-bind-dropdownlist-in-mvc-core-from-database-using-entity-framework) based on city [name](https://yourviews.mindstick.com/view/87450/how-to-generate-a-brand-name-using-linkedin-comprehensive-guide) selected in another city-dropdownlist , both dropdownlists are placed inside the [datalist](https://www.mindstick.com/forum/1797/change-text-on-button-in-datalist-not-working).\ how should i create SelectedIndexChanged [event](https://www.mindstick.com/articles/167719/marquee-hire-benefits-of-event-lighting-hire-london) for city-dropdownlist and to to bind college names to college-dropdownlist? please help me out...!\ \ **this is my [code](https://yourviews.mindstick.com/view/85458/alan-turing-the-mastermind-behind-cracking-the-enigma-code-during-world-war-ii)**\ ```                                                                                                                                                                                                                                                                                                                                                                                                                                        
                                                Priority No.                                                City                                                College                                                                                            Combination
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
                                                                                                                                                                                                    
                                                                                                                                                                                                    
                                                                                            ``` ## Replies ### Reply by Rashmi S Hi...\ Thank you.. i tried your code is working fine...\ \ This is me code which i tried... It may help others...!\ \ **source code :**\ ```                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                                                                                                                                                                                                           
                            Register Number                                                                                Student Name                                                                                 
                                                                                                                    
                                                         Total Number of priorities                                                                                                                     
                   
                       
                    
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          
                                                Priority No.                                                City                                                College                                                                                            Combination
                                                                                                                                                                                                                                                                                                                                                                                                                                       
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
                                                                                                                                                            
                           
                                                                                
                             
                ``` **\ Code behind(.aspx.cs ) :**\ ``` using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Data;namespace PUseatAllot.Student{    public partial class OptionEntry2  : System.Web.UI.Page    {        static int StudId;        BL b = new BL();        static int flg_editOption;        static DataTable t_P_Details;        protected void Page_Load(object sender, EventArgs e)        {            if (!this.IsPostBack)            {                Panel1.Visible = false;                Panel2.Visible = false;                Panel3.Visible = false;                StudId = int.Parse(Session["StudentID"].ToString());                DataTable t_stud = b.Student_Get_StudId(StudId);                if (t_stud.Rows.Count > 0)                {                    lblName.Text = t_stud.Rows[0]["StudentName"].ToString();                    lblRegNo.Text = t_stud.Rows[0]["RegNo"].ToString();                }                //***********************************************************************************                                DataTable t_details = new DataTable();                DataTable tab1 = b.test_Get_CCid(StudId);                if (tab1.Rows.Count > 0)                {                    Panel3.Visible = true;                    //-----------------------------------------------------------------                    DataTable t_proirNo = new DataTable();                    t_proirNo.Columns.Add("PriorityNo", typeof(int));                    for (int i = 1; i <= tab1.Rows.Count; i++)                    {                        DataRow dt = t_proirNo.NewRow();                        dt["PriorityNo"] = i.ToString();                        t_proirNo.Rows.Add(dt);                    }                    DLpriority.DataSource = t_proirNo;                    DLpriority.DataBind();                    foreach (DataListItem item in DLpriority.Items)                    {                        DropDownList ddlCity = (DropDownList)item.FindControl("DDLcity");                        ddlCity.DataSource = b.Cities_GetAll();                        ddlCity.DataTextField = "CityName";                        ddlCity.DataValueField = "CityId";                        ddlCity.DataBind();                        ddlCity.Items.Insert(0, "Select");                        //DropDownList ddlClg = (DropDownList)item.FindControl("DDLcollege");                        //ddlClg.Items.Insert(0, "Select");                        //DropDownList ddlCou = (DropDownList)item.FindControl("DDLcourse");                        //ddlCou.Items.Insert(0, "Select");                    }                    //--------------------------------------------------------------------                    string ccid = null;                    for (int i = 0; i < tab1.Rows.Count; i++)                    {                        ccid = ccid + "'" + tab1.Rows[i]["CCid"].ToString() + "'" + ",";                    }                    ccid = ccid.Substring(0, (ccid.Length - 1));                    DataTable tab2 = b.test_GetClgCouId_CCid(ccid);                    if (tab2.Rows.Count > 0)                    {                                                t_details.Columns.Add("PriorityNo", typeof(int));                        t_details.Columns.Add("CollegeName", typeof(string));                        t_details.Columns.Add("CourseName", typeof(string));                        for (int j = 0; j < tab2.Rows.Count; j++)                        {                            int clgid = int.Parse(tab2.Rows[j]["CollegeId"].ToString());                            int couid = int.Parse(tab2.Rows[j]["CourseId"].ToString());                            DataRow dt = t_details.NewRow();                            DataTable tab3 = b.test_GetClgCouName_ClgCouId(clgid, couid);                            if (tab3.Rows.Count > 0)                            {                                dt["PriorityNo"] = j + 1;                                dt["CollegeName"] = tab3.Rows[0]["CollegeName"].ToString();                                dt["CourseName"] = tab3.Rows[0]["CourseName"].ToString();                                t_details.Rows.Add(dt);                            }                        }                    }                    else                    {                        //if any error msg                    }                }                else                {                    Panel1.Visible = true;                }                //************************************************************************************                if (t_details.Rows.Count > 0)                {                    GVpriority.DataSource = t_details;                    GVpriority.DataBind();                }                else                {                    // add option entry                    for (int i = 1; i <= 20; i++)                    {                        ListItem L = new ListItem(i.ToString());                        DDLcount.Items.Add(L);                    }                    DDLcount.Items.Insert(0, "-- Select --");                    Panel1.Visible = true;                }            }        }        protected void DDLcount_SelectedIndexChanged(object sender, EventArgs e)        {            Panel2.Visible = true;            int priorCount = int.Parse(DDLcount.SelectedItem.Text);            DataTable t_proirNo = new DataTable();            t_proirNo.Columns.Add("PriorityNo", typeof(int));            for (int i = 1; i <= priorCount; i++)            {                DataRow dt = t_proirNo.NewRow();                dt["PriorityNo"] = i.ToString();                t_proirNo.Rows.Add(dt);            }            DLpriority.DataSource = t_proirNo;            DLpriority.DataBind();            foreach (DataListItem item in DLpriority.Items)            {                DropDownList ddlCity = (DropDownList)item.FindControl("DDLcity");                ddlCity.DataSource = b.Cities_GetAll();                ddlCity.DataTextField = "CityName";                ddlCity.DataValueField = "CityId";                ddlCity.DataBind();                ddlCity.Items.Insert(0, "Select");                DropDownList ddlClg = (DropDownList)item.FindControl("DDLcollege");                //ddlClg.DataSource = b.College_GetAll();                //ddlClg.DataTextField = "CollegeName";                //ddlClg.DataValueField = "CollegeId";                //ddlClg.DataBind();                ddlClg.Items.Insert(0, "Select");                DropDownList ddlCou = (DropDownList)item.FindControl("DDLcourse");                //ddlCou.DataSource = b.Course_GetAll();                //ddlCou.DataTextField = "CourseName";                //ddlCou.DataValueField = "CourseId";                //ddlCou.DataBind();                ddlCou.Items.Insert(0, "Select");            }        }        protected void DDLcity_SelectedIndexChanged(object sender, EventArgs e)        {            DropDownList ddlCity = (DropDownList)sender;            if (ddlCity.SelectedIndex != 0)            {                int cityid = int.Parse(ddlCity.SelectedItem.Value);                var row = (DataListItem)ddlCity.NamingContainer;                DropDownList ddlCollege = (DropDownList)row.FindControl("DDLcollege");                ddlCollege.DataSource = b.College_GetAll_CityId(cityid);                ddlCollege.DataTextField = "CollegeName";                ddlCollege.DataValueField = "CollegeId";                ddlCollege.DataBind();                ddlCollege.Items.Insert(0, "select");            }            else            {                var row = (DataListItem)ddlCity.NamingContainer;                DropDownList ddlCollege = (DropDownList)row.FindControl("DDLcollege");                ddlCity.SelectedIndex = 0;                Response.Write("");                ddlCollege.Items.Clear();                ddlCollege.Items.Insert(0, "Select");            }        }        protected void DDLcollege_SelectedIndexChanged(object sender, EventArgs e)        {            DropDownList ddlCollege = (DropDownList)sender;            if (ddlCollege.SelectedIndex != 0)            {                int clgid = int.Parse(ddlCollege.SelectedItem.Value);                var row = (DataListItem)ddlCollege.NamingContainer;                DropDownList ddlCourse = (DropDownList)row.FindControl("DDLcourse");                ddlCourse.DataSource = b.ClgCourse_GetAll_ClgId(clgid);                ddlCourse.DataTextField = "CourseName";                ddlCourse.DataValueField = "CourseId";                ddlCourse.DataBind();                ddlCourse.Items.Insert(0, "select");            }            else            {                var row = (DataListItem)ddlCollege.NamingContainer;                DropDownList ddlCourse = (DropDownList)row.FindControl("DDLcourse");                ddlCollege.SelectedIndex = 0;                Response.Write("");                ddlCourse.Items.Clear();                ddlCourse.Items.Insert(0, "Select");            }        } ``` ### Reply by Sumit Kesarwani Hi Rashmi, I think you try to create the cascading dropdownlist, you can try the following code:\ **UI Code:** ```
     
                                      
           
           
                                           
       
``` **Class:** ``` public class City    {        public int Id { get; set; }        public string CityName { get; set; }        public string College { get; set; }    } ``` **Code Behind:** ``` using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls; namespace CascadingDropdownAspNet{    public partial class Default : System.Web.UI.Page    {        public List Cities = new List();         protected void Page_Load(object sender, EventArgs e)        {            Cities.Add(new City { Id = 1, CityName = "New York", College = "New York College 1" });            Cities.Add(new City { Id = 2, CityName = "New York", College = "New York College 2" });            Cities.Add(new City { Id = 3, CityName = "Boston", College = "Boston College 1" });            Cities.Add(new City { Id = 4, CityName = "Boston", College = "Boston College 2" });             if (!IsPostBack)            {                DDLCity.Items.AddRange(Cities.Select(x => new ListItem(x.CityName)).Distinct().ToArray());             }        }         protected void DDLCity_SelectedIndexChanged(object sender, EventArgs e)        {            DDLCollege.Items.Clear();            var selectedItem = DDLCity.SelectedItem.ToString();             DDLCollege.Items.AddRange(Cities.Where(x => x.CityName == selectedItem).Select(x => new ListItem(x.College)).ToArray());        }    }} ``` \ \ --- Original Source: https://www.mindstick.com/forum/12672/binding-all-college-names-to-a-college-dropdownlist-based-on-data-selected-in-another-city-dropdownlist-both-dropdownlists-are-placed-inside-the-datalist Copyright © MindStick Software Pvt. Ltd. This Markdown version is provided for developers, AI systems, and offline reading.