Call Function (Method) based on ASP.Net DropDownList selection using C#

Hi kankon,

For your codition we use case statement.

Please refer below code.

HTML

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
    <ContentTemplate>
        <table class="auto-style177" dir="rtl">
            <tr class="auto-style178">
                <td style="border: medium solid #000000"></strong><strong>
                    <asp:DropDownList ID="ddlCountries" runat="server" AutoPostBack="true" CssClass="auto-style179" 
                        OnSelectedIndexChanged="Country_Changed">
                    </asp:DropDownList>
                </strong></td>
                <td style="border: medium solid #000000"><strong>
                    <asp:DropDownList ID="ddlStates" runat="server" AutoPostBack="true" CssClass="auto-style179" 
                        OnSelectedIndexChanged="State_Changed">
                    </asp:DropDownList>
                </strong></td>
                <td style="border: medium solid #000000"><strong>
                    <asp:DropDownList ID="ddlCities" runat="server" AutoPostBack="True" CssClass="auto-style179" 
                        OnSelectedIndexChanged="Cities_Changed">
                    </asp:DropDownList>
                </strong></td>
            </tr>
        </table>
        <hr />
        <asp:HiddenField ID="hfSelectedDDL" runat="server" />
        <asp:GridView runat="server" ID="GridView1">
            <Columns>
                <asp:TemplateField HeaderText="حالة الطلب">
                    <ItemTemplate>
                        <asp:Button ID="btnNewRequestsp1" runat="server" CommandArgument="<%# Container.DataItemIndex %>"
                            CssClass="button3" Font-Bold="True" Height="35px" Width="100px" OnClick="OnDeletesp" Text="معتمد"
                            Visible='<%# Eval("CountryId2").ToString() == "Cancelled" ? true : false %>' />
                        <asp:Button ID="btnNewRequestsp2" runat="server" CommandArgument="<%# Container.DataItemIndex %>"
                            CssClass="button3" Font-Bold="True" Height="35px" Width="100px" OnClick="OnCancelsp" Text="غير معتمد"
                            Visible='<%# Eval("CountryId2").ToString() == "return" ? true : false %>' />
                    </ItemTemplate>
                    <FooterStyle Width="100px" />
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>

Namespaces

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

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.BindGridView();
        this.BindGridView2();
    }
}

protected void Country_Changed(object sender, EventArgs e)
{
    hfSelectedDDL.Value = "Country";
}

protected void State_Changed(object sender, EventArgs e)
{
    hfSelectedDDL.Value = "State";
}

protected void Cities_Changed(object sender, EventArgs e)
{
    hfSelectedDDL.Value = "City";
}

protected void OnCancelsp(object sender, EventArgs e)
{
    GridViewRow row = (sender as Button).NamingContainer as GridViewRow;
    string conString = ConfigurationManager.ConnectionStrings["cmConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlCommand cmd = new SqlCommand("UPDATE Table_infoname SET CountryId2 = @CountryId2, dateadd2 = @dateadd2 WHERE id=@id", con))
        {
            string id = GridView1.DataKeys[row.RowIndex].Values[0].ToString();
            cmd.Parameters.AddWithValue("@CountryId2", "Cancelled");
            cmd.Parameters.AddWithValue("@dateadd2", new DateTime(2023, 01, 01));

            cmd.Parameters.AddWithValue("@id", id);
            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
    switch (hfSelectedDDL.Value.ToLower())
    {
        case "country":
            this.BindGridView2();
            break;
        case "state":
            break;
        case "city":
            this.BindGridView();
            break;
        default:
            break;
    }
}

protected void OnDeletesp(object sender, EventArgs e)
{
    GridViewRow row = (sender as Button).NamingContainer as GridViewRow;
    string conString = ConfigurationManager.ConnectionStrings["cmConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(conString))
    {
        using (SqlCommand cmd = new SqlCommand("UPDATE Table_infoname SET CountryId2 = @CountryId2, dateadd2 = @dateadd2 WHERE id=@id", con))
        {
            string id = GridView1.DataKeys[row.RowIndex].Values[0].ToString();
            cmd.Parameters.AddWithValue("@CountryId2", "return");
            cmd.Parameters.AddWithValue("@dateadd2", SqlDbType.DateTime).Value = DateTime.Now;
            cmd.Parameters.AddWithValue("@id", id);
            cmd.Connection = con;
            con.Open();
            cmd.ExecuteNonQuery();
            con.Close();
        }
    }
    this.BindGridView();
}

private void BindGridView()
{
    string constr = ConfigurationManager.ConnectionStrings["cmConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        string query = "SELECT * FROM Table_infoname WHERE Cities = @Cities ";
        using (SqlCommand cmd = new SqlCommand(query))
        {
            cmd.Parameters.AddWithValue("@Cities", ddlCities.SelectedItem.Text);
            GridView1.Columns[6].Visible = false;
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.Connection = con;
                sda.SelectCommand = cmd;
                using (DataTable dt = new DataTable())
                {
                    sda.Fill(dt);
                    GridView1.DataSource = dt;
                    GridView1.DataBind();
                }
            }
        }
    }
}

private void BindGridView2()
{
    string constr = ConfigurationManager.ConnectionStrings["cmConnectionString"].ConnectionString;
    using (SqlConnection con = new SqlConnection(constr))
    {
        string query = "SELECT * FROM Table_infoname WHERE States = @States ";
        using (SqlCommand cmd = new SqlCommand(query))
        {
            cmd.Parameters.AddWithValue("@States", ddlStates.SelectedItem.Text);
            GridView1.Columns[6].Visible = true;
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                cmd.Connection = con;
                sda.SelectCommand = cmd;
                using (DataTable dt = new DataTable())
                {
                    sda.Fill(dt);
                    GridView1.DataSource = dt;
                    GridView1.DataBind();
                }
            }
        }
    }
}