[Solved] DropDownList populated with same record in each row when adding new row to ASP.Net GridView

Hi Mohd.Mekki,

Refer below sample and take its reference and correct your code.

HTML

<div>
    <asp:Label ID="Label1" runat="server">Country</asp:Label>
    <asp:DropDownList runat="server" ID="ddlCounty" Width="200px" AutoPostBack="True">
    </asp:DropDownList>
    <asp:Button ID="btnAppend" runat="server" Text="Append" Width="100px" OnClick="btnAppend_Click" />
</div>
<br />
<div>
    <asp:GridView ID="gvDetails" runat="server" AutoGenerateColumns="False" Width="300px"
        OnRowDataBound="gvDetails_RowDataBound">
        <Columns>
            <asp:BoundField DataField="CountryName" HeaderText="Country" />
            <asp:TemplateField HeaderText="City">
                <ItemTemplate>
                    <asp:DropDownList ID="ddlCity" runat="server" Width="98%">
                    </asp:DropDownList>
                </ItemTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
</div>

Namespaces

C#

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

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

static string Con = ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
SqlConnection sqlCon = new SqlConnection(Con);
SqlCommand cmd;
SqlDataAdapter da;
DataTable dt;
static DataTable dtGrid = new DataTable();

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        cmd = new SqlCommand();
        cmd.Connection = sqlCon;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = "SELECT * FROM Countries";
        try
        {
            dt = new DataTable();
            sqlCon.Open();
            da = new SqlDataAdapter(cmd);
            da.Fill(dt);
            sqlCon.Close();
            ddlCounty.DataSource = dt;
            ddlCounty.DataTextField = "CountryName";
            ddlCounty.DataValueField = "CountryID";
            ddlCounty.DataBind();
            dtGrid.Columns.Add("CountryName");
            dtGrid.Columns.Add("Id");
        }
        catch (Exception ex)
        {
        }
    }
}

protected void btnAppend_Click(object sender, EventArgs e)
{
    int i;
    dtGrid.Rows.Add();
    i = dtGrid.Rows.Count - 1;
    dtGrid.Rows[i]["CountryName"] = ddlCounty.SelectedItem.Text;
    dtGrid.Rows[i]["Id"] = ddlCounty.SelectedValue;

    gvDetails.DataSource = dtGrid;
    gvDetails.DataBind();
}

protected void GetCitiesList(DropDownList ddl, string countryId)
{
    cmd = new SqlCommand();
    cmd.Connection = sqlCon;
    cmd.CommandType = CommandType.Text;
    cmd.CommandText = "SELECT StateID, StateName FROM States WHERE CountryID = " + countryId;
    try
    {
        dt = new DataTable();
        sqlCon.Open();
        da = new SqlDataAdapter(cmd);
        da.Fill(dt);
        sqlCon.Close();
        string s = dt.Rows.Count.ToString();
        ddl.DataSource = dt;
        ddl.DataTextField = "StateName";
        ddl.DataValueField = "StateID";
        ddl.DataBind();
    }
    catch (Exception ex)
    {
    }
}

protected void gvDetails_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        DropDownList[] _ddl = new DropDownList[10];
        _ddl[e.Row.RowIndex] = e.Row.FindControl("ddlCity") as DropDownList;
        GetCitiesList(_ddl[e.Row.RowIndex], dtGrid.Rows[e.Row.RowIndex]["Id"].ToString());
    }
}

VB.Net

Shared Con As String = ConfigurationManager.ConnectionStrings("MyConnectionString").ConnectionString
Private sqlCon As SqlConnection = New SqlConnection(Con)
Private cmd As SqlCommand
Private da As SqlDataAdapter
Private dt As DataTable
Shared dtGrid As DataTable = New DataTable()

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not IsPostBack Then
        cmd = New SqlCommand()
        cmd.Connection = sqlCon
        cmd.CommandType = CommandType.Text
        cmd.CommandText = "SELECT * FROM Countries"
        Try
            dt = New DataTable()
            sqlCon.Open()
            da = New SqlDataAdapter(cmd)
            da.Fill(dt)
            sqlCon.Close()
            ddlCounty.DataSource = dt
            ddlCounty.DataTextField = "CountryName"
            ddlCounty.DataValueField = "CountryID"
            ddlCounty.DataBind()
            dtGrid.Columns.Add("CountryName")
            dtGrid.Columns.Add("Id")
        Catch ex As Exception
        End Try
    End If
End Sub

Protected Sub btnAppend_Click(ByVal sender As Object, ByVal e As EventArgs)
    Dim i As Integer
    dtGrid.Rows.Add()
    i = dtGrid.Rows.Count - 1
    dtGrid.Rows(i)("CountryName") = ddlCounty.SelectedItem.Text
    dtGrid.Rows(i)("Id") = ddlCounty.SelectedValue
    gvDetails.DataSource = dtGrid
    gvDetails.DataBind()
End Sub

Protected Sub GetCitiesList(ByVal ddl As DropDownList, ByVal countryId As String)
    cmd = New SqlCommand()
    cmd.Connection = sqlCon
    cmd.CommandType = CommandType.Text
    cmd.CommandText = "SELECT StateID, StateName FROM States WHERE CountryID = " & countryId
    Try
        dt = New DataTable()
        sqlCon.Open()
        da = New SqlDataAdapter(cmd)
        da.Fill(dt)
        sqlCon.Close()
        Dim s As String = dt.Rows.Count.ToString()
        ddl.DataSource = dt
        ddl.DataTextField = "StateName"
        ddl.DataValueField = "StateID"
        ddl.DataBind()
    Catch ex As Exception
    End Try
End Sub

Protected Sub gvDetails_RowDataBound(ByVal sender As Object, ByVal e As GridViewRowEventArgs)
    If e.Row.RowType = DataControlRowType.DataRow Then
        Dim _ddl As DropDownList() = New DropDownList(9) {}
        _ddl(e.Row.RowIndex) = TryCast(e.Row.FindControl("ddlCity"), DropDownList)
        GetCitiesList(_ddl(e.Row.RowIndex), dtGrid.Rows(e.Row.RowIndex)("Id").ToString())
    End If
End Sub