Pass (Send) multiple DropDownList value and filter ASP.Net GridView in another Page using C# and VB.Net

Hi edaadura,

Check this example. Now please take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

PageA

Country:
<asp:DropDownList ID="ddlCountry" runat="server">
    <asp:ListItem Value="1">--Seletc--</asp:ListItem>
    <asp:ListItem Value="2">UK</asp:ListItem>
    <asp:ListItem Value="3">USA</asp:ListItem>
</asp:DropDownList>
<br />
City:
<asp:DropDownList ID="ddlCity" runat="server">
    <asp:ListItem Value="1">--Seletc--</asp:ListItem>
    <asp:ListItem Value="2">London</asp:ListItem>
    <asp:ListItem Value="3">Seattle</asp:ListItem>
    <asp:ListItem Value="4">Tacoma</asp:ListItem>
    <asp:ListItem Value="5">Redmond</asp:ListItem>
</asp:DropDownList>
<br />
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="Submit_OnClick" />

PageB

<asp:GridView ID="gvEmployee" runat="server" BorderColor="White" BorderWidth="0px"
    AutoGenerateColumns="false" GridLines="None" EmptyDataText="No record found">
    <Columns>
        <asp:TemplateField HeaderText="">
            <ItemStyle HorizontalAlign="Center" Width="50px" />
        </asp:TemplateField>
        <asp:TemplateField HeaderText="">
            <ItemTemplate>
                <asp:HyperLink ID="hplEmployeeID" runat="server" Text='<%# Eval("EmployeeID")%>'
                    NavigateUrl='<%# Eval("EmployeeID","~/parliment/dewan/dn/year/2017_sesi1(J).aspx?id={0}")%>'></asp:HyperLink></h3>
                <asp:Label ID="lblName" runat="server" Text='<%# Eval("Name")%>'></asp:Label><br />
                <asp:Label ID="lblCountry" runat="server" Text='<%# Eval("Country")%>'></asp:Label>
                <asp:Label ID="lblcity" runat="server" Text='<%# Eval("City")%>'></asp:Label><br />
                <hr />
            </ItemTemplate>
        </asp:TemplateField>
    </Columns>
</asp:GridView>

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#

PageA

protected void Submit_OnClick(object sender, EventArgs e)
{
    string country = ddlCountry.SelectedItem.Text.Trim();
    string city = ddlCity.SelectedItem.Text.Trim();
    Response.Redirect("~/PageB.aspx?Country=" + country + "&City=" + city);
}

PageB

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        if (!string.IsNullOrEmpty(Request.QueryString["Country"]) && !string.IsNullOrEmpty(Request.QueryString["City"]))
        {
            using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conString"].ConnectionString))
            {
                using (SqlCommand cmd = new SqlCommand("SELECT EmployeeID,LastName+' '+FirstName Name,Country,City FROM Employees WHERE Country=@country AND City=@city ", con))
                {
                    cmd.CommandType = CommandType.Text;
                    cmd.Parameters.AddWithValue("@country", Request.QueryString["Country"]);
                    cmd.Parameters.AddWithValue("@city", Request.QueryString["City"]);
                    using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
                    {
                        DataTable dt = new DataTable();
                        sda.Fill(dt);
                        this.gvEmployee.DataSource = dt;
                        this.gvEmployee.DataBind();
                    }
                }
            }
        }
    }
}

VB.Net

PageA

Protected Sub Submit_OnClick(ByVal sender As Object, ByVal e As EventArgs)
    Dim country As String = ddlCountry.SelectedItem.Text.Trim()
    Dim city As String = ddlCity.SelectedItem.Text.Trim()
    Response.Redirect("~/PageB.aspx?Country=" & country & "&City=" & city)
End Sub

PageB

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        If Not String.IsNullOrEmpty(Request.QueryString("Country")) AndAlso Not String.IsNullOrEmpty(Request.QueryString("City")) Then
            Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("conString").ConnectionString)
                Using cmd As SqlCommand = New SqlCommand("SELECT EmployeeID,LastName+' '+FirstName Name,Country,City FROM Employees WHERE Country=@country AND City=@city ", con)
                    cmd.CommandType = CommandType.Text
                    cmd.Parameters.AddWithValue("@country", Request.QueryString("Country"))
                    cmd.Parameters.AddWithValue("@city", Request.QueryString("City"))
                    Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
                        Dim dt As DataTable = New DataTable()
                        sda.Fill(dt)
                        Me.gvEmployee.DataSource = dt
                        Me.gvEmployee.DataBind()
                    End Using
                End Using
            End Using
        End If
    End If
End Sub

Screenshot