Kindly check below Design And Code For your Referance.
In .aspx Form
<body>
<form id="form1" runat="server">
<asp:GridView ID="GridView1" HeaderStyle-BackColor="#3AC0F2" HeaderStyle-ForeColor="White"
RowStyle-BackColor="#A1DCF2" AlternatingRowStyle-BackColor="White" AlternatingRowStyle-ForeColor="#000"
runat="server" AutoGenerateColumns="false" AllowPaging="true" OnPageIndexChanging="OnPageIndexChanging">
<Columns>
<asp:BoundField DataField="ContactName" HeaderText="Contact Name" ItemStyle-Width="150px" />
<asp:BoundField DataField="City" HeaderText="City" ItemStyle-Width="100px" />
<asp:BoundField DataField="Country" HeaderText="Country" ItemStyle-Width="100px" />
</Columns>
</asp:GridView>
</form>
</body>
In .cs Code
protected void SearchCountry(object sender, EventArgs e)
{
if (!this.IsPostBack)
{
this.BindGrid();
}
}
private void BindGrid()
{
string strConnString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand("SELECT ContactName,City,Country FROM Customers");
SqlDataAdapter sda = new SqlDataAdapter();
cmd.Connection = con;
sda.SelectCommand = cmd;
DataTable dt = new DataTable();
sda.Fill(dt);
GridView1.DataSource = dt;
GridView1.DataBind();
}