Editable Gridview with Textbox, CheckBox, Radio Button and DropDown List

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;

public partial class _Default : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            showgrid();
        }
    }
    public void showgrid()
    {
        using (SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString))
        {
            DataTable dt = new DataTable();
            sqlcon.Open();
            SqlDataAdapter sda = new SqlDataAdapter("select * from employee ", sqlcon);
            sda.Fill(dt);
            GridView1.DataSource = dt;
            GridView1.DataBind();
        }

    }
    protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
    {
        GridView1.EditIndex = -1;
        showgrid();

    }
    protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
    {

        GridView1.EditIndex = e.NewEditIndex;
        showgrid();
    }
    protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {

        Label lb = (Label)GridView1.Rows[e.RowIndex].FindControl("Label6");
        DropDownList ddl = (DropDownList)GridView1.Rows[e.RowIndex].FindControl("DropDownList1");
        RadioButtonList rbl = (RadioButtonList)GridView1.Rows[e.RowIndex].FindControl("RadioButtonList1");
        CheckBoxList chb = (CheckBoxList)GridView1.Rows[e.RowIndex].FindControl("CheckBoxList2");
        TextBox tx1 = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox1");
        TextBox tx2 = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox2");
        TextBox tx3 = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox3");
        using (SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString))
        {
            sqlcon.Open();
            string sql = "update employee set emp_name='" + tx1.Text + "',emp_address='" + tx2.Text + "',salary='" +
                tx3.Text + "',department='" + ddl.SelectedValue.ToString() + "',maritalstatus='" +
                rbl.SelectedValue.ToString() + "',Active_status='" + chb.SelectedValue.ToString() + "' where emp_id='" +
                lb.Text + "'";
            using (SqlCommand cmd = new SqlCommand(sql))
            {
                cmd.CommandType = CommandType.Text;
                cmd.Connection = sqlcon;
                cmd.ExecuteNonQuery();
                GridView1.EditIndex = -1;
                showgrid();
            }


        }

    }
    public DataTable load_department()
    {
        using (SqlConnection sqlcon = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString))
        {
            DataTable dt = new DataTable();
            SqlDataAdapter sd = new SqlDataAdapter("select DeparmentName,DeparmentId from department", sqlcon);
            sd.Fill(dt);
            return dt;

        }

    }
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        DataRowView drv = e.Row.DataItem as DataRowView;

        if (e.Row.RowType == DataControlRowType.DataRow)
        {
             if ((e.Row.RowState & DataControlRowState.Edit) > 0)
            {
                DropDownList dp = (DropDownList)e.Row.FindControl("ddlOutlet");
                DataTable dt = (DataTable)ViewState["OutletDrpDown"];
                dp.DataSource = dt;
                dp.DataTextField = "DeparmentName";
                dp.DataValueField = " DeparmentId";
                dp.DataBind();
  }
                RadioButtonList rbtnl = (RadioButtonList)e.Row.FindControl("RadioButtonList1");
                rbtnl.SelectedValue = drv[5].ToString();
                CheckBoxList chkb = (CheckBoxList)e.Row.FindControl("CheckBoxList2");
                chkb.SelectedValue = drv[6].ToString();
}
}

            }

        }
    }
}