Set default value in combo box in grid view take data in c#

Question

namespace Combobox_control

{

public partial class Form1 : Form

{

static string constr = "server=techs;database=emp_chetan; user id=sa; password=!nudaspc08;";

string combobox;

SqlConnection con = new SqlConnection(constr);

DataTable dt = new DataTable();

public Form1()

{

InitializeComponent();

}

private void Form1_Load(object sender, EventArgs e)

{

dataGridView1.DataSource = Loaddata();

fillcolumn();

//compair();

}

//fill textbox columns

private DataTable Loaddata()

{

SqlDataAdapter adapter = new SqlDataAdapter();

DataSet ds = new DataSet();

SqlCommand cmd;

string sql= "select * from Gridview_windows ";

cmd = new SqlCommand(sql, con);

adapter.SelectCommand = cmd;

adapter.Fill(ds);

dt = ds.Tables[0];

return dt;

}

// fill combobox columns

private void fillcolumn()

{

DataGridViewComboBoxColumn combo = new DataGridViewComboBoxColumn();

//combo.HeaderText = "Country";

combo.Name = "Selected Country";

ArrayList row = new ArrayList();

//add items for combobox from table

foreach(DataRow dr in dt.Rows)

{

row.Add(dr["Country"].ToString());

}

//add to combo

combo.Items.AddRange(row.ToArray());////

dataGridView1.Columns.Add(combo);

}

private void compair()

{

SqlDataAdapter adapter = new SqlDataAdapter();

DataSet ds = new DataSet();

SqlCommand cmd;

//Int32 i DataGridViewSelectedCellCollection select = new DataGridViewSelectedCellCollection(cmd);

//Int32 selectedColumnCount = dataGridView1.Columns.GetColumnCount(DataGridViewElementStates.Selected);

// Int32 selectedRowCount = dataGridView1.Rows.GetRowCount(DataGridViewElementStates.Selected);

string sql = "select country from Gridview_windows where country='" + combobox + "' ";

cmd = new SqlCommand(sql, con);

con.Open();

SqlDataReader dr = cmd.ExecuteReader();

//adapter.SelectCommand = cmd;

//adapter.Fill(ds);

while(dr.Read())

{

string country = (string)dr["country"];

}

con.Close();

}

}

}