Bind DropDownList based on another DropDownList in GridView Row

Bind DropDownList based on another DropDownList in GridView Row

In this article I have explained, how to bind the DropDownList in the GridView’s ItemTemplate. Sometime we need to bind the DropDownList based on the other DropDownList SelectedItem in the row of the GridView. Here I have populated the first DropDownList, based on its SelectedItem I have popualted the  second DropDownList. Here I have used the DropDownList1’s SelectedIndexChanged event to bind the second DropDownList.

Html Source:

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"

onrowdatabound="GridView1_RowDataBound">

<RowStyle BackColor="#EFF3FB" />

<FooterStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />

<PagerStyle BackColor="#2461BF" ForeColor="White" HorizontalAlign="Center" />

<SelectedRowStyle BackColor="#D1DDF1" Font-Bold="True" ForeColor="#333333" />

<HeaderStyle BackColor="#507CD1" Font-Bold="True" ForeColor="White" />

<EditRowStyle BackColor="#2461BF" />

<AlternatingRowStyle BackColor="White" />

<Columns>

<asp:TemplateField>

<ItemTemplate>

<asp:Label ID="Label1" runat="server" Text='<%# Bind("RowID") %>'></asp:Label>

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField HeaderText="ID">

<ItemTemplate>

<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True" Font-Size="Small" DataSource='<%#getvalues() %>' DataTextField="EventName"

DataValueField="EventID" Width="150px"                             onselectedindexchanged="DropDownList1_SelectedIndexChanged">

</asp:DropDownList>

</ItemTemplate>

</asp:TemplateField>

<asp:TemplateField  HeaderText="Name">

<ItemTemplate>

<asp:DropDownList ID="DropDownList2" runat="server" AutoPostBack="True" Font-Size="Small" Width="150px">

</asp:DropDownList>

</ItemTemplate>

</asp:TemplateField>

</Columns>

</asp:GridView>

Code behind:

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Data.SqlClient;

using System.Data.Sql;

using Microsoft.ApplicationBlocks.Data;

public partial class Default4 : System.Web.UI.Page

{

    MainClass mc = new MainClass();

    public string message;

    public Boolean active = false;

    public long usertype;

    public string con;

    DataSet ds;

    DataRow dr;

    SqlCommand cmd = new SqlCommand();

    DataTable dtEmpty = new DataTable();

    DataTable dtGrid = new DataTable();

    public DataTable dtnull = new DataTable();

    public DataSet dsCust = new DataSet();

    protected void Page_Load(object sender, EventArgs e)

    {

        mc.InitializeCulture();

        if (!(Page.IsPostBack))

        {

            BindGrid();

        }

    }

    public DataTable getvalues()

    {

        try

        {

            DataSet dsEvents = new DataSet();           

            //Your method to fill the dataset from the DataBase

            dsEvents = spcall(1);

            ViewState["EventTable"] = dsEvents;

            return dsEvents.Tables[0];

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }

    protected void BindGrid()

    {

        try

        {

           

            DataTable dtab = dtSort();

            DataRow d = dtEmpty.NewRow();

            d["RowID"] = 0;

            d["UserName"] = null;

            d["Company_Name"] = null;

            dtEmpty.Rows.Add(d);

            GridView1.DataSource = dtEmpty;

            GridView1.DataBind();

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }

    private DataSet spcall(long flag)

    {

        try

        {

            SqlParameter[] sql = new SqlParameter[1];

            sql[0] = new SqlParameter("@flag", SqlDbType.BigInt);

            sql[0].Value = flag;

        ds = SqlHelper.ExecuteDataset(mc.con, CommandType.StoredProcedure, "SP_SelectEvent", sql);

            return ds;

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }

    private DataSet spcallEvent(int _EventId)

    {

        try

        {

            SqlParameter[] sql = new SqlParameter[1];

            sql[0] = new SqlParameter("@EventID", SqlDbType.BigInt);

            sql[0].Value = _EventId;

            ds = SqlHelper.ExecuteDataset(mc.con, CommandType.StoredProcedure, "SP_SelectCustName", sql);

            return ds;

        }

        catch (Exception ex)

        {

            throw ex;

        }

    }

    public DataTable dtSort()

    {

        DataColumn RowID = new DataColumn("RowID");

        dtEmpty.Columns.Add(RowID);

        DataColumn colUname = new DataColumn("UserName");

        dtEmpty.Columns.Add(colUname);

        DataColumn colcmp = new DataColumn("Company_Name");

        dtEmpty.Columns.Add(colcmp);

        return dtEmpty;

    }

    protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)

    {

      

        // Here you can find the row which row's dropdown is fired

        GridViewRow gvr = (GridViewRow)((DropDownList)sender).Parent.Parent;

        // Now convert sender as dropdown which is fired and you can get all the properties   of the dropdown

        DropDownList ddl = (DropDownList)sender;

        // Now fetch the data from the database based on selected drodpwon and bind that data to another dropdown this way

        DropDownList ddlsecond = gvr.FindControl("DropDownList2") as DropDownList;

        // So in this you can get second drodpdown and bind your data

        dsCust = spcallEvent(Convert.ToInt32( ddl.SelectedValue));

        ddlsecond.DataSource = dsCust.Tables[0];

        ddlsecond.DataTextField = "CustName";

        ddlsecond.DataValueField = "ID";

        ddlsecond.DataBind();

    }