Show data in the TextBox after clicking edit Button using C# in ASP.Net

Hi Celv,

I have created a sample that fullfill your requirement

 C#

string constr = ConfigurationManager.ConnectionStrings["Constr"].ConnectionString;
SqlConnection con = new SqlConnection();

protected void Save(object sender, EventArgs e)
{
    string query = @"Insert INTO Customers VALUES('" + txtName.Text.Trim() + "','" + txtCountry.Text.Trim() + "')";
    con = new SqlConnection(constr);
    con.Open();
    using (SqlCommand cmd = new SqlCommand(query, con))
    {
        cmd.ExecuteNonQuery();
    }
    con.Close();
    Response.Redirect(Request.Url.AbsoluteUri);    
}


protected void Update(object sender, EventArgs e)
{
    if (btnEdit.Text == "Edit")
    {
        btnEdit.Text = "Update";
    }
    else
    {
        btnEdit.Text = "Edit";
    }
    if (!string.IsNullOrEmpty(txtName.Text.ToString()) && !string.IsNullOrEmpty(txtCountry.Text.ToString()))
    {
        con = new SqlConnection(constr);
        string query = @"Update Customers Set Name = '" + txtName.Text.Trim() + "'," + "Country = '" + txtCountry.Text.Trim() + "' WHERE CustomerId = " + litId.Text.Trim();
        con.Open();
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            cmd.ExecuteNonQuery();
        }
        con.Close();
        Response.Redirect(Request.Url.AbsoluteUri);
    }
    else
    {
        BindCustomer();
    }
}

private void BindCustomer()
{
    string query = "SELECT CustomerId,Name,Country FROM Customers WHERE CustomerId = (SELECT MAX(CustomerId) FROM Customers)";
    con = new SqlConnection(constr);
    using (SqlCommand cmd = new SqlCommand(query, con))
    {
        con.Open();
        SqlDataReader sdr = cmd.ExecuteReader();
        while (sdr.Read())
        {
            litId.Text = sdr["CustomerId"].ToString();
            txtName.Text = sdr["Name"].ToString();
            txtCountry.Text = sdr["Country"].ToString();
        }
        con.Close();
    }
}

ScreenShot