How to Delete multiple records from Gridview in one shot?

Today, i will tell you how to Delete multiple records from Gridview in one shot without polling database again & again in looping. Just take StringBuilder and append Id with comma.

Our aspx page will look like this:-

<asp:GridView ID="grid_view_employee_details" runat="server" AllowPaging="true" PageSize="5" AutoGenerateColumns="false">
            <Columns>
                <asp:TemplateField>
                    <ItemTemplate>
                        <asp:CheckBox ID="chk_employee_id" runat="server" />
                        <asp:Label ID="lbl_employee_id" runat="server" Text='<%#Eval("id") %>' Visible="false"></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                 <asp:TemplateField HeaderText="Employee Code">
                    <ItemTemplate>                        
                        <asp:Label ID="lbl_employee_code" runat="server" Text='<%#Eval("employee_code") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>

                <asp:TemplateField HeaderText="Employee Name">
                    <ItemTemplate>                        
                        <asp:Label ID="lbl_employee_name" runat="server" Text='<%#Eval("employee_name") %>'></asp:Label>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
        <asp:Button ID="btn_delete" runat="server" Text="Button" OnClick ="btn_delete_Click" />

In the page load:

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            try
            {
                fill_grid();
            }
            catch (Exception ex)
            {
                throw ex;
            }            
        }
    }

private void fill_grid()
    {
        try
        {
            DataTable dt_employee = new DataTable();
            dt_employee.Columns.Add("ID");
            dt_employee.Columns.Add("Employee_Code");
            dt_employee.Columns.Add("Employee_Name");

            dt_employee.Rows.Add("1", "ABC00", "Vishu");
            dt_employee.Rows.Add("2", "ABC01", "Dinesh");
            dt_employee.Rows.Add("3", "ABC02", "Rajesh");
            dt_employee.Rows.Add("4", "ABC03", "Neeraj");
            dt_employee.Rows.Add("5", "ABC04", "Nitin");

            grid_view_employee_details.DataSource = dt_employee;
            grid_view_employee_details.DataBind();
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

In the btn_delete event:-

protected void btn_delete_Click(object sender, EventArgs e)
    {
        System.Text.StringBuilder sb_emp_id = new System.Text.StringBuilder();
        CheckBox chk_employee_id = null;
        Label lbl_employee_id = null;
        string emp_ids = string.Empty;

        try
        {
            if (grid_view_employee_details.Rows.Count > 0)
            {
                foreach (GridViewRow gvr in grid_view_employee_details.Rows )
                {
                    chk_employee_id = gvr.FindControl("chk_employee_id") as CheckBox;
                    lbl_employee_id = gvr.FindControl("lbl_employee_id") as Label;

                    if (chk_employee_id != null && lbl_employee_id != null)
                    {
                        if (chk_employee_id.Checked && !string.IsNullOrEmpty(lbl_employee_id.Text))
                        {
                            sb_emp_id.AppendFormat("{0},", lbl_employee_id.Text.Trim());
                        }
                    }
                }

                emp_ids = sb_emp_id.ToString();

                if (!string.IsNullOrEmpty(emp_ids))
                {
                    emp_ids = emp_ids.TrimEnd(',');

                    //write delete statement and pass emp_id in IN clause as
                    string sql_query = "delete from  table_name where id in('" + emp_ids + "')";
                    //write rest of the code
                }
                else
                {
                    //show message that says please select at-least one checkbox
                    return;
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }